Repository: rezn-project/rezn-dsl
Pull request #7: IR signature generation based on ed25519 algorithm
Author: login: andreamancuso
Created: 2025-05-26T23:11:30Z | Merged: 2025-05-28T22:03:15Z



<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit

- **New Features**
  - Introduced cryptographic signing and verification for Rezn IR bundles using Ed25519 signatures.
  - Added a command-line tool to compile and sign Rezn DSL programs, producing signed JSON bundles.
  - Added a command-line tool to verify the authenticity of signed bundles.
  - Implemented a Unix socket server for signing and verifying bundles via JSON-based requests.
  - Provided example signed configuration files and updated documentation with usage instructions.

- **Bug Fixes**
  - Improved error handling and reporting for parsing, signing, and verification operations.

- **Chores**
  - Added new dependencies for cryptographic functionality and updated build configurations.
  - Updated .gitignore to exclude key files.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->


Diff:
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 55e64d4..042ce6e 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -19,6 +19,11 @@ jobs:
         with:
           ocaml-compiler: 5.3.0
 
+      - name: Install system dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y libsodium-dev
+
       - name: Install deps
         run: opam install . --deps-only --with-test
 
@@ -31,11 +36,19 @@ jobs:
       - name: Copy binary
         run: |
           mkdir -p dist
-          cp _build/default/bin/main.exe dist/reznc
+          cp _build/default/reznc/main.exe dist/reznc
+          cp _build/default/server/main.exe dist/server
+          cp _build/default/verify/main.exe dist/verify
+      
+      - name: Make binaries executable
+        run: |
+          chmod +x dist/reznc
+          chmod +x dist/server
+          chmod +x dist/verify
 
       - name: Upload release artifacts
         uses: softprops/action-gh-release@v2
         with:
-          files: dist/reznc
+          files: dist/*
         env:
           GITHUB_TOKEN: ${{ secrets.GH_PAT }}
diff --git a/.gitignore b/.gitignore
index a18e084..5aba1bf 100644
--- a/.gitignore
+++ b/.gitignore
@@ -27,3 +27,6 @@ setup.log
 
 # Local OPAM switch
 _opam/
+
+rezn.key
+rezn.pub
diff --git a/README.md b/README.md
index 9645318..2f1c98a 100644
--- a/README.md
+++ b/README.md
@@ -67,6 +67,91 @@ Output (formatted):
 ]
 ```
 
+### Running the Unix socket
+
+`./_build/default/server/main.exe ` -> `Signer service ready on /tmp/rezn_signer.sock`
+
+#### Setup
+
+The commands here assume you have installed `socat`, i.e.
+
+`sudo apt install socat`
+
+#### Signing
+
+**Once a bundle has been signed and verified, treat the JSON as strictly read-only.**
+
+Do **not** reformat, reserialize, pretty-print, or modify the JSON in any way.
+
+> Even changes that appear trivial — such as field reordering, whitespace adjustments,
+> or float formatting — will cause the signature to become invalid. The bundle exists
+> to be **verified, not edited**. If you need to change the program, update the original
+> `.rezn` source and re-sign it.
+
+`cat ./examples/basic-example.rezn | jq -Rs '{op: "sign", source: .}' | socat - UNIX-CONNECT:/tmp/rezn_signer.sock`
+
+should emit (below example is pretty-printed):
+
+```json
+{
+  "status": "ok",
+  "bundle": {
+    "program": [
+      {
+        "kind": "pod",
+        "name": "nginx",
+        "fields": {
+          "image": "nginx:alpine",
+          "replicas": 2,
+          "ports": [
+            80,
+            443
+          ],
+          "secure": true
+        }
+      },
+      {
+        "kind": "service",
+        "name": "nginx-service",
+        "fields": {
+          "selector": "nginx",
+          "port": 80
+        }
+      },
+      {
+        "kind": "volume",
+        "name": "shared-cache",
+        "fields": {
+          "mount": "/cache"
+        }
+      },
+      {
+        "kind": "enum",
+        "name": "env",
+        "options": [
+          "prod",
+          "staging",
+          "dev"
+        ]
+      }
+    ],
+    "signature": {
+      "algorithm": "ed25519",
+      "sig": "FHD0qZUpHsma5OPUc7mvNvjrE44Oc/R27GEUrtdf8gkb/azm4uTUcgY2H9Szo4Otw3VlYLhOjZlErnEffv6oCA==",
+      "pub": "MWf0xdBZrWtyrMhpvrv3y0AAtEjHYgMLviEsWtadang="
+    }
+  }
+}
+```
+
+#### Verifying
+
+`jq '{op: "verify", bundle: .}' ./examples/basic-example.ir.json | socat - UNIX-CONNECT:/tmp/rezn_signer.sock`
+
+Should emit
+
+`{"status":"ok","verified":true}`
+
 ## Build
 
 Requires OCaml, Dune, and Menhir.
diff --git a/bin/main.ml b/bin/main.ml
deleted file mode 100644
index be30ad2..0000000
--- a/bin/main.ml
+++ /dev/null
@@ -1,22 +0,0 @@
-open Rezn.Frontend
-
-let () =
-  if Array.length Sys.argv <> 2 then begin
-    Printf.eprintf "Usage: %s <file.rezn>\n" Sys.argv.(0);
-    exit 1
-  end;
-
-  let filename = Sys.argv.(1) in
-  try
-    let prog = parse_file filename in
-    let json = Rezn.Codegen.program_to_json prog in
-    Yojson.Basic.pretty_to_channel stdout json;
-    print_newline ()
-  with
-  | Rezn.Frontend.Parse_error msg ->
-      Printf.eprintf "%s\n" msg;
-      exit 1
-  | Rezn.Frontend.Lexer_error msg ->
-      Printf.eprintf "Lexer error: %s\n" msg;
-      exit 1
-  
diff --git a/dune-project b/dune-project
index a9b10cd..5d85b4d 100644
--- a/dune-project
+++ b/dune-project
@@ -21,6 +21,12 @@
  (synopsis "DSL for Rezn")
  (description "Rezn is a domain-specific language (DSL) for Rezn")
  (depends
+  (base64
+   (and
+    (>= 3.5.0)
+    (< 4.0.0)))
+  digestif
+  sodium
   (menhir
    (>= 2.1.0))
   yojson
diff --git a/examples/.gitkeep b/examples/.gitkeep
deleted file mode 100644
index e69de29..0000000
diff --git a/examples/basic-example.ir.json b/examples/basic-example.ir.json
new file mode 100644
index 0000000..7ae7fe5
--- /dev/null
+++ b/examples/basic-example.ir.json
@@ -0,0 +1,34 @@
+{
+  "program": [
+    {
+      "kind": "pod",
+      "name": "nginx",
+      "fields": {
+        "image": "nginx:alpine",
+        "replicas": 2,
+        "ports": [ 443, 80 ],
+        "secure": true
+      }
+    },
+    {
+      "kind": "service",
+      "name": "nginx-service",
+      "fields": { "selector": "nginx", "port": 80 }
+    },
+    {
+      "kind": "volume",
+      "name": "shared-cache",
+      "fields": { "mount": "/cache" }
+    },
+    {
+      "kind": "enum",
+      "name": "env",
+      "options": [ "prod", "staging", "dev" ]
+    }
+  ],
+  "signature": {
+    "algorithm": "ed25519",
+    "sig": "FHD0qZUpHsma5OPUc7mvNvjrE44Oc/R27GEUrtdf8gkb/azm4uTUcgY2H9Szo4Otw3VlYLhOjZlErnEffv6oCA==",
+    "pub": "MWf0xdBZrWtyrMhpvrv3y0AAtEjHYgMLviEsWtadang="
+  }
+}
diff --git a/lib/codegen.ml b/lib/codegen.ml
index bfaaea8..c0c52de 100644
--- a/lib/codegen.ml
+++ b/lib/codegen.ml
@@ -38,5 +38,5 @@ let decl_to_json = function
         ("options", `List (List.map (fun s -> `String s) options))
       ]
 
-let program_to_json (prog : program) : Yojson.Basic.t =
+let program_to_json (prog : program) : Yojson.Safe.t =
   `List (List.map decl_to_json prog)
diff --git a/lib/dune b/lib/dune
index 4f89c90..3d3771a 100644
--- a/lib/dune
+++ b/lib/dune
@@ -1,7 +1,7 @@
 (library
  (name rezn)
- (modules ast frontend lexer parser codegen)
- (libraries yojson))
+ (modules ast frontend lexer keys parser codegen sign verify)
+ (libraries base64 digestif sodium unix yojson))
 
 (menhir
  (modules parser))
diff --git a/lib/frontend.ml b/lib/frontend.ml
index 07a71dd..a690ee3 100644
--- a/lib/frontend.ml
+++ b/lib/frontend.ml
@@ -31,3 +31,7 @@ let parse_string (source : string) : program =
       raise (Parse_error msg)
   | Failure msg ->
       raise (Lexer_error msg)
+
+let sign_program_string (src : string) (sk : Sodium.secret Sodium.Sign.key) : Yojson.Safe.t =
+  let prog = parse_string src in
+  Sign.generate_signed_bundle prog sk
\ No newline at end of file
diff --git a/lib/keys.ml b/lib/keys.ml
new file mode 100644
index 0000000..27d8939
--- /dev/null
+++ b/lib/keys.ml
@@ -0,0 +1,37 @@
+let key_file = "rezn.key"
+let pub_file = "rezn.pub"
+
+let ensure_keys () =
+  try
+    let fd =
+      Unix.openfile key_file [ Unix.O_WRONLY; Unix.O_CREAT; Unix.O_EXCL ] 0o600
+    in
+    Printf.printf "Generating new Ed25519 keypair...\n%!";
+    Sodium.Random.stir ();
+    let sk, pk = Sodium.Sign.random_keypair () in
+    let sk_bytes = Sodium.Sign.Bytes.of_secret_key sk in
+    let pk_bytes = Sodium.Sign.Bytes.of_public_key pk in
+
+    let out = Unix.out_channel_of_descr fd in
+    Out_channel.output_bytes out sk_bytes;
+    Out_channel.close out;
+
+    Out_channel.with_open_bin pub_file (fun out_pub ->
+      Out_channel.output_bytes out_pub pk_bytes
+    )
+  with Unix.Unix_error (Unix.EEXIST, _, _) ->
+    () (* Key already exists — do nothing *)
+
+let get_sk () : Sodium.secret Sodium.Sign.key =
+  try
+    let sk_bytes =
+      In_channel.with_open_bin key_file In_channel.input_all
+      |> Bytes.of_string
+    in
+    let sk = Sodium.Sign.Bytes.to_secret_key sk_bytes in
+    sk
+  with
+  | Sys_error msg -> 
+      failwith ("Failed to read secret key file: " ^ msg)
+  | Sodium.Verification_failure ->
+      failwith ("Invalid secret key format in file: " ^ key_file)
\ No newline at end of file
diff --git a/lib/sign.ml b/lib/sign.ml
new file mode 100644
index 0000000..3184889
--- /dev/null
+++ b/lib/sign.ml
@@ -0,0 +1,27 @@
+let sign_json sk json_str =
+  let msg = Bytes.of_string json_str in
+  Sodium.Sign.Bytes.sign sk msg
+
+let generate_signed_bundle (prog : Ast.program) (sk : Sodium.secret Sodium.Sign.key) : Yojson.Safe.t =
+  let json = Codegen.program_to_json prog in
+  let json_str = Yojson.Safe.to_string json in
+
+  (* Hash the canonical program *)
+  let hash = Digestif.SHA256.digest_string json_str in
+  let hex = Digestif.SHA256.to_hex hash in
+  Printf.printf "Signature generation hash: %s\n%!" hex;
+
+  let signature = Sodium.Sign.Bytes.sign_detached sk (Bytes.of_string json_str) in
+  let signature_bytes = Sodium.Sign.Bytes.of_signature signature in
+  let sig_b64 = Base64.encode_exn (Bytes.to_string signature_bytes) in
+  let pk = Sodium.Sign.secret_key_to_public_key sk in
+  let pub_b64 = Base64.encode_exn (Bytes.to_string (Sodium.Sign.Bytes.of_public_key pk)) in
+  `Assoc [
+    "program", json;
+    "signature", `Assoc [
+      "algorithm", `String "ed25519";
+      "sig", `String sig_b64;
+      "pub", `String pub_b64;
+    ]
+  ]
+
diff --git a/lib/verify.ml b/lib/verify.ml
new file mode 100644
index 0000000..39bd9e6
--- /dev/null
+++ b/lib/verify.ml
@@ -0,0 +1,40 @@
+let verify_bundle (bundle : Yojson.Safe.t) : bool =
+  try
+    match bundle with
+    | `Assoc assoc_list ->
+        (match List.assoc_opt "program" assoc_list, List.assoc_opt "signature" assoc_list with
+         | Some program_json, Some (`Assoc sig_fields) ->
+             (match List.assoc_opt "algorithm" sig_fields, 
+                    List.assoc_opt "sig" sig_fields,
+                    List.assoc_opt "pub" sig_fields with
+              | Some (`String "ed25519"), Some (`String sig_b64), Some (`String pub_b64) ->
+                  let json_str = Yojson.Safe.to_string program_json in
+                  let msg = Bytes.of_string json_str in
+
+                  let signature =
+                    match Base64.decode sig_b64 with
+                    | Ok sig_str -> Bytes.of_string sig_str |> Sodium.Sign.Bytes.to_signature
+                    | Error _ -> failwith "Invalid base64 signature"
+                  in
+                  let pubkey =
+                    match Base64.decode pub_b64 with
+                    | Ok pub_str -> Bytes.of_string pub_str |> Sodium.Sign.Bytes.to_public_key
+                    | Error _ -> failwith "Invalid base64 public key"
+                  in
+
+                  (try
+                     Sodium.Sign.Bytes.verify pubkey signature msg;
+                     true
+                   with _ -> false)
+              | _ -> 
+                  Printf.eprintf "[verify] Invalid signature fields.\n%!";
+                  false)
+         | _ -> 
+             Printf.eprintf "[verify] Invalid bundle format.\n%!";
+             false)
+    | _ -> 
+        Printf.eprintf "[verify] Invalid bundle format.\n%!";
+        false
+  with _ -> 
+    Printf.eprintf "[verify] Error during verification.\n%!";
+    false
diff --git a/rezn-dsl.opam b/rezn-dsl.opam
index 897b662..a25c441 100644
--- a/rezn-dsl.opam
+++ b/rezn-dsl.opam
@@ -9,6 +9,9 @@ homepage: "https://github.com/rezn-project/rezn-dsl"
 bug-reports: "https://github.com/rezn-project/rezn-dsl/issues"
 depends: [
   "dune" {>= "3.17"}
+  "base64" {>= "3.5.0" & < "4.0.0"}
+  "digestif"
+  "sodium"
   "menhir" {>= "2.1.0"}
   "yojson"
   "ppx_expect"
diff --git a/bin/dune b/reznc/dune
similarity index 53%
rename from bin/dune
rename to reznc/dune
index d473888..d848a96 100644
--- a/bin/dune
+++ b/reznc/dune
@@ -1,4 +1,4 @@
 (executable
  (name main)
  (modules main)
- (libraries rezn yojson))
+ (libraries rezn cmdliner yojson))
diff --git a/reznc/main.ml b/reznc/main.ml
new file mode 100644
index 0000000..2008586
--- /dev/null
+++ b/reznc/main.ml
@@ -0,0 +1,56 @@
+open Rezn.Frontend
+open Cmdliner
+
+let run input_file output_file_opt =
+  try
+    Rezn.Keys.ensure_keys ();
+
+    let sk = Rezn.Keys.get_sk () in
+
+    let prog = parse_file input_file in
+    let bundle = Rezn.Sign.generate_signed_bundle prog sk in
+    let json_str = Yojson.Safe.pretty_to_string bundle in
+
+    (match output_file_opt with
+     | Some path ->
+         let oc = open_out path in
+         output_string oc json_str;
+         close_out oc
+     | None ->
+         print_endline json_str);
+
+    ()
+  with
+  | Rezn.Frontend.Parse_error msg ->
+      prerr_endline msg;
+      exit 1
+  | Rezn.Frontend.Lexer_error msg ->
+      prerr_endline ("Lexer error: " ^ msg);
+      exit 1
+  | exn ->
+      prerr_endline ("Unhandled error: " ^ Printexc.to_string exn);
+      exit 2
+
+let input_file =
+  let doc = "The .rezn source file to compile and sign." in
+  Arg.(required & pos 0 (some file) None & info [] ~docv:"REZN_FILE" ~doc)
+
+let output_file =
+  let doc = "Optional output path. If omitted, signed bundle is printed to stdout." in
+  Arg.(value & opt (some string) None & info ["o"; "output"] ~docv:"FILE" ~doc)
+
+let cmd_term =
+  Term.(const run $ input_file $ output_file)
+
+let cmd_info =
+  let doc = "Compile and cryptographically sign a Rezn IR program" in
+  let man = [
+    `S Manpage.s_description;
+    `P "Reads a .rezn file, emits JSON IR, and attaches an Ed25519 signature to it.";
+    `P "The signature proves authenticity and prevents tampering of the infrastructure spec.";
+  ] in
+  Cmd.info "reznc" ~doc ~man
+
+let cmd = Cmd.v cmd_info cmd_term
+
+let () = Stdlib.exit @@ Cmd.eval cmd
diff --git a/server/dune b/server/dune
new file mode 100644
index 0000000..1e55369
--- /dev/null
+++ b/server/dune
@@ -0,0 +1,4 @@
+(executable
+ (name main)
+ (modules main)
+ (libraries rezn cmdliner yojson unix))
diff --git a/server/main.ml b/server/main.ml
new file mode 100644
index 0000000..8426d61
--- /dev/null
+++ b/server/main.ml
@@ -0,0 +1,65 @@
+let socket_path = "/tmp/rezn_signer.sock"
+
+let buffer_size = 1024
+
+
+let cleanup_and_exit sock =
+  Unix.close sock;
+  if Sys.file_exists socket_path then Unix.unlink socket_path;
+  exit 0
+
+let () =
+  let sock = ref None in
+  Sys.set_signal Sys.sigterm (Sys.Signal_handle (fun _ -> 
+    match !sock with Some s -> cleanup_and_exit s | None -> exit 0));
+  Sys.set_signal Sys.sigint (Sys.Signal_handle (fun _ -> 
+    match !sock with Some s -> cleanup_and_exit s | None -> exit 0));
+  if Sys.file_exists socket_path then Unix.unlink socket_path;
+  let socket = Unix.socket Unix.PF_UNIX Unix.SOCK_STREAM 0 in
+  sock := Some socket;
+  Unix.bind socket (Unix.ADDR_UNIX socket_path);
+  Unix.listen socket 5;
+
+  Rezn.Keys.ensure_keys ();
+
+  let sk = Rezn.Keys.get_sk () in
+
+  Printf.printf "Signer service ready on %s\n%!" socket_path;
+
+  let rec loop () =
+    let (client, _) = Unix.accept socket in
+    let in_chan = Unix.in_channel_of_descr client in
+    let out_chan = Unix.out_channel_of_descr client in
+    try
+      let buf = Buffer.create buffer_size in
+        (try while true do Buffer.add_channel buf in_chan buffer_size done
+        with End_of_file -> ());
+      let req_body = Buffer.contents buf in
+
+      let response =
+        try
+          match Yojson.Safe.from_string req_body with
+          | `Assoc [ ("op", `String "sign"); ("source", `String src) ] ->
+              let bundle = Rezn.Frontend.sign_program_string src sk in
+              `Assoc [ "status", `String "ok"; "bundle", bundle ]
+          | `Assoc [ ("op", `String "verify"); ("bundle", bundle_json) ] ->
+            let valid = Rezn.Verify.verify_bundle bundle_json in
+            `Assoc [ "status", `String "ok"; "verified", `Bool valid ]
+          | _ ->
+              `Assoc [ "status", `String "error"; "message", `String "Invalid request format" ]
+        with exn ->
+          `Assoc [ "status", `String "error"; "message", `String (Printexc.to_string exn) ]
+      in
+      let result = Yojson.Safe.to_string response in
+      output_string out_chan result;
+      flush out_chan;
+      close_in in_chan;
+      close_out out_chan;
+      loop ()
+    with exn ->
+      Printf.eprintf "Connection error: %s\n%!" (Printexc.to_string exn);
+      close_in_noerr in_chan;
+      close_out_noerr out_chan;
+      loop ()
+  in
+  loop ()
diff --git a/test.ir.json b/test.ir.json
new file mode 100644
index 0000000..8939384
--- /dev/null
+++ b/test.ir.json
@@ -0,0 +1,34 @@
+{
+  "program": [
+    {
+      "kind": "pod",
+      "name": "nginx",
+      "fields": {
+        "image": "nginx:alpine",
+        "replicas": 2,
+        "ports": [ 443, 80 ],
+        "secure": true
+      }
+    },
+    {
+      "kind": "service",
+      "name": "nginx-service",
+      "fields": { "selector": "nginx", "port": 80 }
+    },
+    {
+      "kind": "volume",
+      "name": "shared-cache",
+      "fields": { "mount": "/cache" }
+    },
+    {
+      "kind": "enum",
+      "name": "env",
+      "options": [ "prod", "staging", "dev" ]
+    }
+  ],
+  "signature": {
+    "algorithm": "ed25519",
+    "sig": "FHD0qZUpHsma5OPUc7mvNvjrE44Oc/R27GEUrtdf8gkb/azm4uTUcgY2H9Szo4Otw3VlYLhOjZlErnEffv6oCA==",
+    "pub": "MWf0xdBZrWtyrMhpvrv3y0AAtEjHYgMLviEsWtadang="
+  }
+}
\ No newline at end of file
diff --git a/test/parser_tests.ml b/test/parser_tests.ml
index 4bcdbe8..25c16ae 100644
--- a/test/parser_tests.ml
+++ b/test/parser_tests.ml
@@ -1,9 +1,6 @@
-open Rezn.Frontend
-open Yojson.Basic
-
 let%expect_test "parsing a minimal pod" =
   let source = {| pod "x" { image = "nginx" } |} in
-  let prog = parse_string source in
+  let prog = Rezn.Frontend.parse_string source in
   let json = Rezn.Codegen.program_to_json prog in
-  json |> pretty_to_string |> print_endline;
+  json |> Yojson.Safe.pretty_to_string |> print_endline;
   [%expect {| [ { "kind": "pod", "name": "x", "fields": { "image": "nginx" } } ] |}]
diff --git a/verify/dune b/verify/dune
new file mode 100644
index 0000000..d848a96
--- /dev/null
+++ b/verify/dune
@@ -0,0 +1,4 @@
+(executable
+ (name main)
+ (modules main)
+ (libraries rezn cmdliner yojson))
diff --git a/verify/main.ml b/verify/main.ml
new file mode 100644
index 0000000..7ba9624
--- /dev/null
+++ b/verify/main.ml
@@ -0,0 +1,41 @@
+open Cmdliner
+
+let run input_file =
+  try
+    let json = Yojson.Safe.from_file input_file in
+    let is_valid = Rezn.Verify.verify_bundle json in
+
+    if is_valid then (
+      print_endline "✔ Signature is valid.";
+      exit 0
+    ) else (
+      prerr_endline "✘ Signature is INVALID.";
+      exit 1
+    )
+  with
+  | Yojson.Json_error msg ->
+      prerr_endline ("Failed to parse JSON: " ^ msg);
+      exit 2
+  | exn ->
+      prerr_endline ("Unhandled error: " ^ Printexc.to_string exn);
+      exit 3
+
+let input_file =
+  let doc = "The signed bundle file to verify (must be JSON)." in
+  Arg.(required & pos 0 (some file) None & info [] ~docv:"SIGNED_JSON" ~doc)
+
+let cmd_term =
+  Term.(const run $ input_file)
+
+let cmd_info =
+  let doc = "Verify a signed Rezn IR bundle" in
+  let man = [
+    `S Manpage.s_description;
+    `P "Verifies that the signature in a signed bundle is valid.";
+    `P "Reads a JSON file containing {program, signature}, and checks the Ed25519 signature.";
+  ] in
+  Cmd.info "rezn-verify" ~doc ~man
+
+let cmd = Cmd.v cmd_info cmd_term
+
+let () = Stdlib.exit @@ Cmd.eval cmd


Reviews:
user: login: coderabbitai[bot]
body: **Actionable comments posted: 5**

<details>
<summary>🧹 Nitpick comments (4)</summary><blockquote>

<details>
<summary>test.ir.json (1)</summary><blockquote>

`29-33`: **Consider adding documentation for signature verification.**

While the signature format is clear, consider adding comments or documentation explaining how to verify these signatures, especially for users who need to validate the signed bundles.


Would you like me to help create documentation or examples for signature verification workflows?

</blockquote></details>
<details>
<summary>lib/sign.ml (1)</summary><blockquote>

`19-21`: **Function name & return value mismatch**

`sign_json` returns the *signed message* (`signature‖msg`) produced by `Sodium.Sign.Bytes.sign`, not a detached signature as the name suggests.  
Because the function is currently unused (the caller uses `sign_detached`), either:

1. Rename the function (`sign_attached`) **or**
2. Return the detached signature to align with the advertised semantics.

Keeping dead / misleading code around is confusing and risks accidental misuse later.

</blockquote></details>
<details>
<summary>bin/main.ml (2)</summary><blockquote>

`4-12`: **Base-64 helper already exists – drop the extra copy**

`Base64.encode_exn (Bytes.to_string …)` performs an unnecessary copy.  
`Base64.encode_bytes` (from the same library) takes `Bytes.t` directly and avoids reallocating the entire buffer:

```diff
-  let sig_b64 = Base64.encode_exn (Bytes.to_string signature_bytes) in
+  let sig_b64 = Base64.encode_bytes signature_bytes in
…
-  let pub_b64 = Base64.encode_exn (Bytes.to_string (Sodium.Sign.Bytes.of_public_key pk)) in
+  let pub_b64 = Base64.encode_bytes (Sodium.Sign.Bytes.of_public_key pk) in
```

A tiny optimisation, but essentially free.

---

`36-40`: **Ensure output file is properly closed on exceptions**

`output_string` could raise (e.g. disk full). Wrap the write in `Fun.protect` (or `Out_channel.with_open_bin`) to guarantee `close_out` is executed.

```diff
-     | Some path ->
-         let oc = open_out path in
-         output_string oc json_str;
-         close_out oc
+     | Some path ->
+         Fun.protect
+           ~finally:(fun () -> close_out_noerr oc)
+           (fun () ->
+              let oc = open_out path in
+              output_string oc json_str)
```

Minor, but increases robustness.

</blockquote></details>

</blockquote></details>

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* `dune-project` (1 hunks)
* `lib/codegen.ml` (1 hunks)
* `lib/dune` (1 hunks)
* `lib/sign.ml` (1 hunks)
* `rezn-dsl.opam` (1 hunks)
* `test.ir.json` (1 hunks)
* `test/parser_tests.ml` (1 hunks)

</details>

<details>
<summary>🔇 Additional comments (7)</summary><blockquote>

<details>
<summary>.gitignore (1)</summary>

`31-32`: **Excellent security practice!**

Adding the Ed25519 key files to `.gitignore` is crucial for security. This prevents accidentally committing private keys to version control, which would be a serious security vulnerability.

</details>
<details>
<summary>lib/dune (1)</summary>

`3-4`: <details>
<summary>❌ Incorrect review comment</summary>

**Add missing base64 library dependency.**

The `sign` module has been added to the modules list and `sodium` library has been added to dependencies, but the `base64` library is missing from the libraries list despite being declared as a project dependency.


If the `sign` module uses base64 encoding (which is common for Ed25519 signatures), you'll need to add it to the libraries list:

```diff
- (libraries yojson sodium))
+ (libraries yojson base64 sodium))
```


Verify if the sign module uses base64 functionality with this script:

---

🏁 Script executed:

```shell
#!/bin/bash
# Check if the sign module uses base64 functions
rg -A 3 -B 3 "Base64" lib/sign.ml
```

Length of output: 33

---



</details>

**Remove base64 from the libraries suggestion**

A search for “Base64” in lib/sign.ml returned no references, so the `sign` module does not use any base64 encoding/decoding APIs. You can safely keep the libraries list as:

```diff
- (libraries yojson base64 sodium))
+ (libraries yojson sodium))
```



> Likely an incorrect or invalid review comment.

</details>
<details>
<summary>test/parser_tests.ml (2)</summary>

`3-3`: **LGTM! Good explicit module qualification.**

The change to explicitly qualify `Rezn.Frontend.parse_string` improves code readability and removes dependency on open statements.

---

`5-5`: **LGTM! Consistent migration to Yojson.Safe.**

The change from `Yojson.Basic` to `Yojson.Safe` aligns with the broader codebase migration and maintains consistency with the updated type annotations in `lib/codegen.ml`.

</details>
<details>
<summary>bin/dune (1)</summary>

`4-4`: **LGTM! Necessary dependencies for new functionality.**

The addition of `base64` and `cmdliner` libraries supports the new CLI interface and cryptographic signature encoding features introduced in this PR.

</details>
<details>
<summary>lib/codegen.ml (1)</summary>

`41-41`: **LGTM! Consistent type annotation update.**

The change from `Yojson.Basic.t` to `Yojson.Safe.t` aligns with the codebase migration and maintains type consistency with the usage in tests and main application.

</details>
<details>
<summary>test.ir.json (1)</summary>

`1-34`: **Well-structured signed JSON bundle format.**

The JSON structure effectively demonstrates the new signed bundle format with:
- Clear separation between program data and signature metadata
- Proper ed25519 algorithm specification
- Base64-encoded signature and public key fields

This serves as a good example of the expected output format for the new signing functionality.

</details>

</blockquote></details>

</details>

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<details>
<summary>♻️ Duplicate comments (1)</summary><blockquote>

<details>
<summary>lib/sign.ml (1)</summary><blockquote>

`4-17`: _⚠️ Potential issue_

**Secret-key creation still vulnerable to TOCTOU & world-read leaks**  
The exact same issue was highlighted in a previous review and remains unfixed.

Use `Unix.openfile ... O_EXCL 0o600` (atomic create + strict perms) and drop the `Sys.file_exists` check. See prior diff suggestion.

</blockquote></details>

</blockquote></details>

<details>
<summary>🧹 Nitpick comments (4)</summary><blockquote>

<details>
<summary>lib/frontend.ml (1)</summary><blockquote>

`35-37`: **Consider re-using existing parsing logic to avoid double work**

`sign_program_string` calls `parse_string` and then `Sign.generate_signed_bundle`.  
In `cli/main.ml` you parse the file again and call `generate_signed_bundle` directly.  
Exposing `sign_program_string` is perfectly fine, but it would be cleaner (and less error-prone) if downstream callers consistently used a single helper (`sign_program_string`) instead of re-implementing the flow.

No action required—just something to keep in mind while the API is still malleable.

</blockquote></details>
<details>
<summary>server/main.ml (1)</summary><blockquote>

`1-8`: **Restrict socket path permissions**

Anyone on the machine can connect to `/tmp/rezn_signer.sock`.  
Consider placing the socket in `$XDG_RUNTIME_DIR` or `$HOME/.cache/rezn/`, and set `umask 077` (or call `Unix.chmod`) before binding to prevent unprivileged users from hijacking the signer.

</blockquote></details>
<details>
<summary>lib/sign.ml (2)</summary><blockquote>

`28-32`: **Remove noisy debug print or promote it to a proper logger**

`Printf.printf "OCaml hash: %s\n%!" hex;` is executed on every call, polluting stdout for library consumers. Either:

- Delete the line, or
- Guard it behind a `--verbose` CLI flag / logging facility.

---

`19-22`: **`sign_json` is unused**

Unless you foresee external callers, consider removing it to keep the public surface minimal.

</blockquote></details>

</blockquote></details>

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* `dune-project` (1 hunks)
* `lib/dune` (1 hunks)
* `lib/frontend.ml` (1 hunks)
* `lib/sign.ml` (1 hunks)
* `rezn-dsl.opam` (1 hunks)
* `server/dune` (1 hunks)
* `server/main.ml` (1 hunks)
* `test.ir.json` (1 hunks)

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* `lib/dune` (1 hunks)
* `lib/keys.ml` (1 hunks)
* `lib/sign.ml` (1 hunks)
* `rezn-dsl.opam` (1 hunks)
* `server/main.ml` (1 hunks)

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<details>
<summary>🧹 Nitpick comments (3)</summary><blockquote>

<details>
<summary>README.md (3)</summary><blockquote>

`70-70`: **Use consistent heading levels**: The majority of top-level sections (`Build`, `Run`, `Running Tests`) use `##`. Consider changing the `### Running the Unix socket` heading to `## Running the Unix socket` to align with the existing structure.

---

`72-72`: **Remove trailing space inside code span**: There's an extra space before the closing backtick in ``./_build/default/server/main.exe ``. Removing it resolves the MD038 lint warning. 

```diff
- `./_build/default/server/main.exe `
+ `./_build/default/server/main.exe`
```

<details>
<summary>🧰 Tools</summary>

<details>
<summary>🪛 markdownlint-cli2 (0.17.2)</summary>

72-72: Spaces inside code span elements
null

(MD038, no-space-in-code)

</details>

</details>

---

`79-128`: **Clarify example JSON semantics and key naming**:
1. The `ports` array is shown as `[443, 80]`, whereas the original input was `[80, 443]`. If the service canonicalizes or sorts arrays, mention that behavior.
2. The signature object uses keys `sig` and `pub`. Consider using more descriptive names like `signature` and `public_key` for clarity.

Please verify the ordering logic and update the example (and/or field names) accordingly.

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<details>
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72-72: Spaces inside code span elements
null

(MD038, no-space-in-code)

</details>

</details>

</details>

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<details>
<summary>♻️ Duplicate comments (2)</summary><blockquote>

<details>
<summary>README.md (1)</summary><blockquote>

`76-76`: **Document requirement for canonical JSON.**



Signature verification is sensitive to JSON formatting. The example uses `jq -Rs`, but you should explicitly note that the JSON must be canonical (sorted keys, no extra whitespace) to ensure signatures validate correctly.

Add this note after the example command:

```diff
 `cat ./examples/basic-example.rezn | jq -Rs '{op: "sign", source: .}' | socat - UNIX-CONNECT:/tmp/rezn_signer.sock`
+
+> **Note:** Ensure the JSON passed to the signer is in canonical form (sorted keys, no extra whitespace) to guarantee a consistent signature.
```

</blockquote></details>
<details>
<summary>server/main.ml (1)</summary><blockquote>

`20-23`: _🛠️ Refactor suggestion_

**Addresses previous issue but lacks input size protection.**

The buffer-based approach correctly addresses the previous `in_channel_length` issue for socket reading. However, there's no protection against excessively large inputs that could cause memory exhaustion.



Add input size limits:

```diff
   try
-    let buf = Buffer.create 1024 in
-      (try while true do Buffer.add_channel buf in_chan 1024 done
-      with End_of_file -> ());
-    let req_body = Buffer.contents buf in
+    let max_size = 1024 * 1024 in (* 1MB limit *)
+    let buf = Buffer.create 1024 in
+    let rec read_with_limit remaining =
+      if remaining <= 0 then failwith "Request too large"
+      else
+        try
+          let chunk_size = min 1024 remaining in
+          Buffer.add_channel buf in_chan chunk_size;
+          read_with_limit (remaining - chunk_size)
+        with End_of_file -> ()
+    in
+    read_with_limit max_size;
+    let req_body = Buffer.contents buf in
```

</blockquote></details>

</blockquote></details>

<details>
<summary>🧹 Nitpick comments (1)</summary><blockquote>

<details>
<summary>README.md (1)</summary><blockquote>

`72-72`: **Fix spacing in code span elements.**

Remove extra spaces inside the code span elements as flagged by markdownlint.



```diff
-`./_build/default/server/main.exe ` -> `Signer service ready on /tmp/rezn_signer.sock`
+`./_build/default/server/main.exe` -> `Signer service ready on /tmp/rezn_signer.sock`
```

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72-72: Spaces inside code span elements
null

(MD038, no-space-in-code)

</details>

</details>

</blockquote></details>

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* `.gitignore` (1 hunks)
* `README.md` (1 hunks)
* `examples/basic-example.ir.json` (1 hunks)
* `lib/dune` (1 hunks)
* `lib/keys.ml` (1 hunks)
* `lib/sign.ml` (1 hunks)
* `lib/verify.ml` (1 hunks)
* `reznc/dune` (1 hunks)
* `reznc/main.ml` (1 hunks)
* `server/main.ml` (1 hunks)
* `verify/dune` (1 hunks)
* `verify/main.ml` (1 hunks)

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* reznc/dune
* verify/dune
* examples/basic-example.ir.json
* lib/sign.ml

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72-72: Spaces inside code span elements
null

(MD038, no-space-in-code)

</details>

</details>

</details>

<details>
<summary>🔇 Additional comments (9)</summary><blockquote>

<details>
<summary>lib/keys.ml (1)</summary>

`1-37`: **LGTM! Key management implementation is secure and well-handled.**

The implementation addresses the error handling concerns from previous reviews:

- File operations are properly wrapped in try-catch blocks
- Specific error messages for file access and key format issues  
- Secure file permissions (0o600) for the secret key
- Proper resource management with automatic cleanup
- Handles the common case of existing keys gracefully

The cryptographic operations follow best practices with proper random seeding.

</details>
<details>
<summary>reznc/main.ml (1)</summary>

`1-57`: **LGTM! Well-structured CLI tool with good error handling.**

The implementation demonstrates good practices:

- Clear separation of concerns with dedicated error handling for different exception types
- Proper integration with the key management and signing modules
- Well-documented command-line interface using Cmdliner
- Appropriate exit codes for different error conditions

The tool provides a clean interface for the core functionality of compiling and signing Rezn programs.

</details>
<details>
<summary>verify/main.ml (5)</summary>

`1-2`: **LGTM!**

Clean and appropriate imports for the functionality.

---

`3-22`: **Well-structured verification function with comprehensive error handling.**

The function correctly:
- Reads and parses JSON input files
- Calls the verification logic
- Provides clear success/failure feedback
- Uses appropriate exit codes (0=valid, 1=invalid, 2=parse error, 3=other)

The error handling covers both JSON parsing errors and general exceptions appropriately.

---

`23-25`: **Good command-line argument definition.**

The argument definition properly:
- Requires a positional file argument
- Validates file existence with `file` type
- Provides clear documentation

---

`27-37`: **Excellent CLI documentation and structure.**

The command info includes comprehensive documentation with proper manual sections explaining the functionality and Ed25519 signature verification.

---

`39-42`: **Standard Cmdliner command execution pattern.**

Proper command construction and execution following Cmdliner conventions.

</details>
<details>
<summary>server/main.ml (2)</summary>

`9-11`: **Good key management integration.**

Proper initialization of cryptographic keys before starting the server.

---

`25-38`: **Well-structured request processing with comprehensive error handling.**

The pattern matching correctly handles both "sign" and "verify" operations with appropriate JSON structure validation. Exception handling ensures the server continues running despite individual request failures.

</details>

</blockquote></details>

</details>

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submitted_at: 2025-05-28T21:43:18Z
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<details>
<summary>♻️ Duplicate comments (1)</summary><blockquote>

<details>
<summary>README.md (1)</summary><blockquote>

`74-84`: **Canonical JSON requirement addressed**  
The documentation now clearly warns that any reordering, whitespace changes, or reserialization will break the signature. This aligns with the previous suggestion to explicitly document the need for canonical JSON formatting.

</blockquote></details>

</blockquote></details>

<details>
<summary>🧹 Nitpick comments (1)</summary><blockquote>

<details>
<summary>README.md (1)</summary><blockquote>

`70-73`: **Refine the service startup snippet**  
The inline code spans contain trailing spaces and the arrow notation is ambiguous. Consider converting this to a fenced code block and removing extra spaces inside backticks to satisfy MD038 (no spaces inside code spans).  

For example:
```diff
- `./_build/default/server/main.exe ` -> `Signer service ready on /tmp/rezn_signer.sock`
+ ```bash
+ ./_build/default/server/main.exe
+ # Signer service ready on /tmp/rezn_signer.sock
+ ```  
```

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72-72: Spaces inside code span elements
null

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<details>
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72-72: Spaces inside code span elements
null

(MD038, no-space-in-code)

</details>

</details>

</details>

<details>
<summary>🔇 Additional comments (1)</summary><blockquote>

<details>
<summary>README.md (1)</summary>

`141-147`: **Verification example is clear**  
The verify command and expected response are accurate and self-contained.

</details>

</blockquote></details>

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<details>
<summary>README.md (2)</summary><blockquote>

`72-72`: **Remove trailing space inside code span**  
The inline code `` `./_build/default/server/main.exe ` `` contains a trailing space. Consider using `` `./_build/default/server/main.exe` `` or formatting the command and its output as a multi-line code block for clarity.

<details>
<summary>🧰 Tools</summary>

<details>
<summary>🪛 markdownlint-cli2 (0.17.2)</summary>

72-72: Spaces inside code span elements
null

(MD038, no-space-in-code)

</details>

</details>

---

`78-78`: **Use non-interactive install flag**  
Consider making the command non-interactive and consistent with other steps:

```diff
- `sudo apt install socat`
+ `sudo apt-get install -y socat`
```

</blockquote></details>
<details>
<summary>.github/workflows/release.yml (5)</summary><blockquote>

`22-26`: **Consider caching OPAM dependencies to speed up CI builds**  
You can add an `actions/cache` step before installing system dependencies to persist your OPAM switch across runs:

```diff
+      - name: Cache OPAM dependencies
+        uses: actions/cache@v3
+        with:
+          path: ~/.opam
+          key: ${{ runner.os }}-opam-${{ hashFiles('**/opam', '**/dune-project') }}
       - name: Install system dependencies
```

---

`39-41`: **Leverage `dune install` to simplify artifact collection**  
Rather than manually copying each binary, you could run something like:

```yaml
- name: Install to dist
  run: |
    mkdir -p dist/bin
    opam exec -- dune install --destdir dist
```

This automatically installs all executables into `dist/bin`, reducing maintenance when adding new tools.

---

`43-47`: **Combine copy and permission setting using `install`**  
Use the Unix `install` command to copy files with mode in one step:

```diff
-          cp _build/default/reznc/main.exe dist/reznc
-          chmod +x dist/reznc
+          install -m755 _build/default/reznc/main.exe dist/reznc
```

Apply the same pattern for `server` and `verify`.

---

`42-42`: **Remove trailing spaces**  
There's a trailing space on this blank line, which may trigger YAML lint errors.

<details>
<summary>🧰 Tools</summary>

<details>
<summary>🪛 YAMLlint (1.37.1)</summary>

[error] 42-42: trailing spaces

(trailing-spaces)

</details>

</details>

---

`52-52`: **Expand file glob for nested artifacts**  
If you ever add subdirectories or supplementary files under `dist`, consider changing to `dist/**/*` to catch all nested files:

```diff
-          files: dist/*
+          files: dist/**/*
```

</blockquote></details>

</blockquote></details>

<details>
<summary>📜 Review details</summary>

**Configuration used: CodeRabbit UI**
**Review profile: CHILL**
**Plan: Pro**


<details>
<summary>📥 Commits</summary>

Reviewing files that changed from the base of the PR and between e8c635d52bca3dcba4f4e200d8c934e87461d085 and 6d1a4d11c5043fd2c9d04fb0b7b04e3e4165cdd9.

</details>

<details>
<summary>📒 Files selected for processing (2)</summary>

* `.github/workflows/release.yml` (2 hunks)
* `README.md` (1 hunks)

</details>

<details>
<summary>🧰 Additional context used</summary>

<details>
<summary>🪛 YAMLlint (1.37.1)</summary>

<details>
<summary>.github/workflows/release.yml</summary>

[error] 42-42: trailing spaces

(trailing-spaces)

</details>

</details>
<details>
<summary>🪛 markdownlint-cli2 (0.17.2)</summary>

<details>
<summary>README.md</summary>

72-72: Spaces inside code span elements
null

(MD038, no-space-in-code)

</details>

</details>

</details>

<details>
<summary>🔇 Additional comments (6)</summary><blockquote>

<details>
<summary>README.md (3)</summary>

`70-70`: **Introduce Unix socket section**  
The new "Running the Unix socket" header clearly outlines how to start the signer service. Great addition to the docs!

---

`74-74`: **Add Setup subheading for socket**  
The "#### Setup" subheading correctly scopes installation instructions under the Unix socket section.

---

`76-76`: **Document `socat` prerequisite**  
Mentioning the requirement to install `socat` ensures users won’t encounter missing tool errors.

</details>
<details>
<summary>.github/workflows/release.yml (3)</summary>

`22-25`: **Add system dependency `libsodium-dev` for cryptographic operations**  
Great addition—installing `libsodium-dev` ensures the OCaml `sodium` package will build correctly on Ubuntu.

---

`39-41`: **Verify executable paths on Ubuntu runner**  
The workflow copies from `_build/default/<pkg>/main.exe`. On Linux, Dune typically emits executables without a `.exe` suffix. Please confirm these paths match your actual artifacts or adjust to `main` (no `.exe`) if needed.

---

`52-53`: **Verify GitHub token secret configuration**  
The action uses `GITHUB_TOKEN: ${{ secrets.GH_PAT }}`. Please ensure that `GH_PAT` is defined in your repository secrets; otherwise, use the built-in `${{ secrets.GITHUB_TOKEN }}`.

</details>

</blockquote></details>

</details>

<!-- This is an auto-generated comment by CodeRabbit for review status -->
state: COMMENTED
author_association: NONE
submitted_at: 2025-05-28T21:53:36Z

Review comments:
diff_hunk: @@ -9,6 +9,8 @@ homepage: "https://github.com/rezn-project/rezn-dsl"
 bug-reports: "https://github.com/rezn-project/rezn-dsl/issues"
 depends: [
   "dune" {>= "3.17"}
+  "base64"
+  "sodium"
path: rezn-dsl.opam
user: login: coderabbitai[bot]
body: _🛠️ Refactor suggestion_

**Consider adding version constraints for cryptographic dependencies.**

The new `base64` and `sodium` dependencies lack version constraints, which could lead to compatibility issues across different environments or over time. For cryptographic libraries, it's especially important to ensure consistent behavior.


Consider adding version constraints:

```diff
-  "base64"
-  "sodium"
+  "base64" {>= "3.5.0"}
+  "sodium" {>= "0.6.0"}
```


<!-- suggestion_start -->

<details>
<summary>📝 Committable suggestion</summary>

> ‼️ **IMPORTANT**
> Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

```suggestion
  "base64" {>= "3.5.0"}
  "sodium" {>= "0.6.0"}
```

</details>

<!-- suggestion_end -->

<details>
<summary>🤖 Prompt for AI Agents</summary>

```
In rezn-dsl.opam around lines 12 to 13, the dependencies "base64" and "sodium"
are listed without version constraints. To ensure consistent behavior and avoid
compatibility issues, specify appropriate version constraints for these
cryptographic libraries by adding version ranges or exact versions that are
known to work with your project.
```

</details>

<!-- This is an auto-generated reply by CodeRabbit -->
created_at: 2025-05-26T23:13:54Z
author_association: NONE
diff_hunk: @@ -21,6 +21,8 @@
  (synopsis "DSL for Rezn")
  (description "Rezn is a domain-specific language (DSL) for Rezn")
  (depends
+  base64
+  sodium
path: dune-project
user: login: coderabbitai[bot]
body: _🛠️ Refactor suggestion_

**Add version constraints to match package requirements.**

These dependency additions are consistent with the opam file changes, which is good. However, consider adding version constraints here as well to ensure consistency and reproducible builds.


Apply this diff to add version constraints:

```diff
-  base64
-  sodium
+  (base64 (>= 3.5.0))
+  (sodium (>= 0.6.0))
```


<!-- suggestion_start -->

<details>
<summary>📝 Committable suggestion</summary>

> ‼️ **IMPORTANT**
> Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

```suggestion
  (base64 (>= 3.5.0))
  (sodium (>= 0.6.0))
```

</details>

<!-- suggestion_end -->

<details>
<summary>🤖 Prompt for AI Agents</summary>

```
In dune-project around lines 24 to 25, the dependencies 'base64' and 'sodium'
are added without version constraints. To ensure consistency and reproducible
builds, add explicit version constraints matching those specified in the opam
file for these packages. Update the dependency lines to include the appropriate
version ranges or exact versions as required.
```

</details>

<!-- This is an auto-generated reply by CodeRabbit -->
created_at: 2025-05-26T23:13:54Z
author_association: NONE
diff_hunk: @@ -0,0 +1,21 @@
+let key_file = "rezn.key"
+let pub_file = "rezn.pub"
+
+let ensure_keys () =
+  if not (Sys.file_exists key_file) then (
+    Printf.printf "Generating new Ed25519 keypair...\n%!";
+    Sodium.Random.stir ();
+    let sk, pk = Sodium.Sign.random_keypair () in
+    let sk_bytes = Sodium.Sign.Bytes.of_secret_key sk in
+    let pk_bytes = Sodium.Sign.Bytes.of_public_key pk in
+    let out = open_out_bin key_file in
+    output_bytes out sk_bytes;
+    close_out out;
+    let out_pub = open_out_bin pub_file in
+    output_bytes out_pub pk_bytes;
+    close_out out_pub
+  )
path: lib/sign.ml
user: login: coderabbitai[bot]
body: _🛠️ Refactor suggestion_

_⚠️ Potential issue_

**Protect the secret key on disk & avoid TOCTOU race**

`ensure_keys` writes the secret key with the process’ default umask – on many systems that is `0o022`, which still grants read-access to *every* user (mode `644`).  
Moreover, `Sys.file_exists` + `open_out_bin` is subject to a TOCTOU race; an attacker could pre-create or swap the file between the two calls.

```diff
-  if not (Sys.file_exists key_file) then (
+  (* Generate the pair only if the secret-key file does not exist.
+     Use O_CREAT|O_EXCL to make the creation atomic and restrict the
+     permissions to 0o600 to avoid leaking the private key. *)
+  if not (Sys.file_exists key_file) then (
     Printf.printf "Generating new Ed25519 keypair...\n%!";
     Sodium.Random.stir ();
     let sk, pk = Sodium.Sign.random_keypair () in
     let sk_bytes = Sodium.Sign.Bytes.of_secret_key sk in
     let pk_bytes = Sodium.Sign.Bytes.of_public_key pk in
-    let out = open_out_bin key_file in
+    let out =
+      Unix.openfile key_file [Unix.O_WRONLY; Unix.O_CREAT; Unix.O_EXCL] 0o600
+      |> Unix.out_channel_of_descr
+    in
     output_bytes out sk_bytes;
     close_out out;
-    let out_pub = open_out_bin pub_file in
+    let out_pub =
+      Unix.openfile pub_file [Unix.O_WRONLY; Unix.O_CREAT; Unix.O_TRUNC] 0o644
+      |> Unix.out_channel_of_descr
+    in
     output_bytes out_pub pk_bytes;
     close_out out_pub
   )
```

This hardens the key-handling path and eliminates a common security pitfall.  
 


<!-- suggestion_start -->

<details>
<summary>📝 Committable suggestion</summary>

> ‼️ **IMPORTANT**
> Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

```suggestion
let ensure_keys () =
  (* Generate the pair only if the secret-key file does not exist.
     Use O_CREAT|O_EXCL to make the creation atomic and restrict the
     permissions to 0o600 to avoid leaking the private key. *)
  if not (Sys.file_exists key_file) then (
    Printf.printf "Generating new Ed25519 keypair...\n%!";
    Sodium.Random.stir ();
    let sk, pk = Sodium.Sign.random_keypair () in
    let sk_bytes = Sodium.Sign.Bytes.of_secret_key sk in
    let pk_bytes = Sodium.Sign.Bytes.of_public_key pk in
    let out =
      Unix.openfile key_file [Unix.O_WRONLY; Unix.O_CREAT; Unix.O_EXCL] 0o600
      |> Unix.out_channel_of_descr
    in
    output_bytes out sk_bytes;
    close_out out;
    let out_pub =
      Unix.openfile pub_file [Unix.O_WRONLY; Unix.O_CREAT; Unix.O_TRUNC] 0o644
      |> Unix.out_channel_of_descr
    in
    output_bytes out_pub pk_bytes;
    close_out out_pub
  )
```

</details>

<!-- suggestion_end -->

<details>
<summary>🤖 Prompt for AI Agents</summary>

```
In lib/sign.ml around lines 4 to 17, the current code writes the secret key file
with default permissions, which may expose it to other users, and uses
Sys.file_exists followed by open_out_bin, creating a TOCTOU race. To fix this,
replace the existence check and file creation with an atomic operation that
creates the file with restrictive permissions (e.g., 0o600) to protect the
secret key, and handle the case where the file already exists without a separate
existence check. Use low-level file creation functions that allow setting
permissions atomically to avoid race conditions.
```

</details>

<!-- This is an auto-generated comment by CodeRabbit -->
created_at: 2025-05-26T23:13:54Z
author_association: NONE
diff_hunk: @@ -1,22 +1,79 @@
 open Rezn.Frontend
+open Cmdliner
 
-let () =
-  if Array.length Sys.argv <> 2 then begin
-    Printf.eprintf "Usage: %s <file.rezn>\n" Sys.argv.(0);
-    exit 1
-  end;
+let generate_signed_bundle (prog : Rezn.Ast.program) (sk : Sodium.secret Sodium.Sign.key) : Yojson.Safe.t =
+  let json = Rezn.Codegen.program_to_json prog in
+  let json_str = Yojson.Safe.pretty_to_string json in
+  let signature = Sodium.Sign.Bytes.sign_detached sk (Bytes.of_string json_str) in
+  let signature_bytes = Sodium.Sign.Bytes.of_signature signature in
+  let sig_b64 = Base64.encode_exn (Bytes.to_string signature_bytes) in
+  let pk = Sodium.Sign.secret_key_to_public_key sk in
+  let pub_b64 = Base64.encode_exn (Bytes.to_string (Sodium.Sign.Bytes.of_public_key pk)) in
+  `Assoc [
+    "program", json;
+    "signature", `Assoc [
+      "algorithm", `String "ed25519";
+      "sig", `String sig_b64;
+      "pub", `String pub_b64; (* Should be flag-driven? *)
+    ]
+  ]
 
-  let filename = Sys.argv.(1) in
+let run input_file output_file_opt =
   try
-    let prog = parse_file filename in
-    let json = Rezn.Codegen.program_to_json prog in
-    Yojson.Basic.pretty_to_channel stdout json;
-    print_newline ()
+    Rezn.Sign.ensure_keys ();
+
+    let sk_bytes =
+      let ic = open_in_bin Rezn.Sign.key_file in
+      really_input_string ic 64 |> Bytes.of_string
+    in
+    let sk = Sodium.Sign.Bytes.to_secret_key sk_bytes in
+
+    let prog = parse_file input_file in
+    let bundle = generate_signed_bundle prog sk in
+    let json_str = Yojson.Safe.pretty_to_string bundle in
+
+    (match output_file_opt with
+     | Some path ->
+         let oc = open_out path in
+         output_string oc json_str;
+         close_out oc
+     | None ->
+         print_endline json_str);
+
+    exit 0
path: bin/main.ml
user: login: coderabbitai[bot]
body: _🛠️ Refactor suggestion_

**Let Cmdliner drive the exit code instead of `exit 0`**

Calling `exit` inside `run` short-circuits Cmdliner’s own exit-status handling and prevents it from emitting helpful error messages (e.g. bad CLI usage).  
Return `()` from the term and let `Cmd.eval` decide.

```diff
-    exit 0
+    ()
```

`Stdlib.exit @@ Cmd.eval cmd` at the bottom is already sufficient.



<!-- suggestion_start -->

<details>
<summary>📝 Committable suggestion</summary>

> ‼️ **IMPORTANT**
> Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

```suggestion
    (match output_file_opt with
     | Some path ->
         let oc = open_out path in
         output_string oc json_str;
         close_out oc
     | None ->
         print_endline json_str);

    ()
```

</details>

<!-- suggestion_end -->

<details>
<summary>🤖 Prompt for AI Agents</summary>

```
In bin/main.ml around lines 35 to 43, remove the explicit call to exit 0 at the
end of the match expression. Instead, let the function return unit () and allow
Cmdliner to handle the exit status. This means you should delete the line with
exit 0 and ensure the term returns () so that Cmd.eval can manage the program's
exit code and error messages properly.
```

</details>

<!-- This is an auto-generated comment by CodeRabbit -->
created_at: 2025-05-26T23:13:54Z
author_association: NONE
diff_hunk: @@ -1,22 +1,79 @@
 open Rezn.Frontend
+open Cmdliner
 
-let () =
-  if Array.length Sys.argv <> 2 then begin
-    Printf.eprintf "Usage: %s <file.rezn>\n" Sys.argv.(0);
-    exit 1
-  end;
+let generate_signed_bundle (prog : Rezn.Ast.program) (sk : Sodium.secret Sodium.Sign.key) : Yojson.Safe.t =
+  let json = Rezn.Codegen.program_to_json prog in
+  let json_str = Yojson.Safe.pretty_to_string json in
+  let signature = Sodium.Sign.Bytes.sign_detached sk (Bytes.of_string json_str) in
+  let signature_bytes = Sodium.Sign.Bytes.of_signature signature in
+  let sig_b64 = Base64.encode_exn (Bytes.to_string signature_bytes) in
+  let pk = Sodium.Sign.secret_key_to_public_key sk in
+  let pub_b64 = Base64.encode_exn (Bytes.to_string (Sodium.Sign.Bytes.of_public_key pk)) in
+  `Assoc [
+    "program", json;
+    "signature", `Assoc [
+      "algorithm", `String "ed25519";
+      "sig", `String sig_b64;
+      "pub", `String pub_b64; (* Should be flag-driven? *)
+    ]
+  ]
 
-  let filename = Sys.argv.(1) in
+let run input_file output_file_opt =
   try
-    let prog = parse_file filename in
-    let json = Rezn.Codegen.program_to_json prog in
-    Yojson.Basic.pretty_to_channel stdout json;
-    print_newline ()
+    Rezn.Sign.ensure_keys ();
+
+    let sk_bytes =
+      let ic = open_in_bin Rezn.Sign.key_file in
+      really_input_string ic 64 |> Bytes.of_string
+    in
+    let sk = Sodium.Sign.Bytes.to_secret_key sk_bytes in
+
path: bin/main.ml
user: login: coderabbitai[bot]
body: _⚠️ Potential issue_

**File descriptor leak & brittle length assumption when loading the secret key**

1. `open_in_bin` is never closed – the FD leaks on every invocation.
2. The code assumes the secret key is exactly *64* bytes.  
   Libsodium may change its layout (it already supports 32-byte “seed” keys).  Reading whatever is in the file is safer.

```diff
-    let sk_bytes =
-      let ic = open_in_bin Rezn.Sign.key_file in
-      really_input_string ic 64 |> Bytes.of_string
-    in
+    let sk_bytes =
+      In_channel.with_open_bin Rezn.Sign.key_file In_channel.input_all
+      |> Bytes.of_string
+    in
```

Using `In_channel.with_open_bin` (or `Fun.protect ~finally`) guarantees closure in the face of exceptions and removes the magic constant.



<!-- suggestion_start -->

<details>
<summary>📝 Committable suggestion</summary>

> ‼️ **IMPORTANT**
> Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

```suggestion
    let sk_bytes =
      In_channel.with_open_bin Rezn.Sign.key_file In_channel.input_all
      |> Bytes.of_string
    in
    let sk = Sodium.Sign.Bytes.to_secret_key sk_bytes in
```

</details>

<!-- suggestion_end -->

<details>
<summary>🤖 Prompt for AI Agents</summary>

```
In bin/main.ml around lines 25 to 30, the file descriptor opened by open_in_bin
is never closed, causing a resource leak, and the code assumes the secret key
length is always 64 bytes, which is brittle. Replace open_in_bin with
In_channel.with_open_bin to safely open and automatically close the file, and
read the entire file content without hardcoding the length to 64 bytes, thus
avoiding assumptions about key size.
```

</details>

<!-- This is an auto-generated comment by CodeRabbit -->
created_at: 2025-05-26T23:13:55Z
author_association: NONE
diff_hunk: @@ -9,6 +9,8 @@ homepage: "https://github.com/rezn-project/rezn-dsl"
 bug-reports: "https://github.com/rezn-project/rezn-dsl/issues"
 depends: [
   "dune" {>= "3.17"}
+  "base64"
+  "sodium"
path: rezn-dsl.opam
user: login: yawaramin
body: This is a generated file, so it should not be edited in PRs.
created_at: 2025-05-27T01:25:22Z
author_association: NONE
diff_hunk: @@ -0,0 +1,21 @@
+let key_file = "rezn.key"
+let pub_file = "rezn.pub"
+
+let ensure_keys () =
+  if not (Sys.file_exists key_file) then (
+    Printf.printf "Generating new Ed25519 keypair...\n%!";
+    Sodium.Random.stir ();
+    let sk, pk = Sodium.Sign.random_keypair () in
+    let sk_bytes = Sodium.Sign.Bytes.of_secret_key sk in
+    let pk_bytes = Sodium.Sign.Bytes.of_public_key pk in
+    let out = open_out_bin key_file in
path: lib/sign.ml
user: login: yawaramin
body: Probably should also use 'protected' open to ensure no file leaks here ie `Out_channel.with_open_bin`. Same on L14.
created_at: 2025-05-27T01:27:18Z
author_association: NONE
diff_hunk: @@ -21,6 +21,8 @@
  (synopsis "DSL for Rezn")
  (description "Rezn is a domain-specific language (DSL) for Rezn")
  (depends
+  base64
+  sodium
path: dune-project
user: login: yawaramin
body: I'd recommend also setting an upper bound to try to follow SemVer:

```
(base64 (and (>= 3.5.0) (< 4.0.0)))
```
created_at: 2025-05-27T01:28:40Z
author_association: NONE
diff_hunk: @@ -9,6 +9,8 @@ homepage: "https://github.com/rezn-project/rezn-dsl"
 bug-reports: "https://github.com/rezn-project/rezn-dsl/issues"
 depends: [
   "dune" {>= "3.17"}
+  "base64"
+  "sodium"
path: rezn-dsl.opam
user: login: coderabbitai[bot]
body: @yawaramin You're absolutely right! I apologize for missing the comment at the top of the file that clearly states "This file is generated by dune, edit dune-project instead." 

My suggestion to add version constraints should have been directed at the `dune-project` file instead, since that's where the dependency declarations are actually maintained and where they would be generated from.

Thank you for catching this important distinction between generated and source files!



🐰
   ( o.o )
    > ^ <
 (thoughtful)

---

<details>
<summary>✏️ Learnings added</summary>

```
Learnt from: yawaramin
PR: rezn-project/rezn-dsl#7
File: rezn-dsl.opam:12-13
Timestamp: 2025-05-27T01:29:52.049Z
Learning: The rezn-dsl.opam file is generated by dune from dune-project and should not be edited directly in PRs. Any dependency changes should be made in the dune-project file instead.
```

> Note: Learnings are effective only in the context of similar code segments. To apply general coding guidelines, please configure [review instructions](https://docs.coderabbit.ai/guides/review-instructions). You can manage existing learnings in the [app](https://app.coderabbit.ai/learnings).

</details>


<!-- <agentComponentType>chat-answer</agentComponentType> -->

<!-- <rawResChunk><answer>@yawaramin You're absolutely right! I apologize for missing the comment at the top of the file that clearly states "This file is generated by dune, edit dune-project instead." 

My suggestion to add version constraints should have been directed at the `dune-project` file instead, since that's where the dependency declarations are actually maintained and where they would be generated from.

Thank you for catching this important distinction between generated and source files!



🐰
   ( o.o )
    > ^ <
 (thoughtful)

---

<details>
<summary>✏️ Learnings added</summary>

```
Learnt from: yawaramin
PR: rezn-project/rezn-dsl#7
File: rezn-dsl.opam:12-13
Timestamp: 2025-05-27T01:29:52.049Z
Learning: The rezn-dsl.opam file is generated by dune from dune-project and should not be edited directly in PRs. Any dependency changes should be made in the dune-project file instead.
```

> Note: Learnings are effective only in the context of similar code segments. To apply general coding guidelines, please configure [review instructions](https://docs.coderabbit.ai/guides/review-instructions). You can manage existing learnings in the [app](https://app.coderabbit.ai/learnings).

</details>

</answer></rawResChunk> -->

<!-- This is an auto-generated reply by CodeRabbit -->
created_at: 2025-05-27T01:29:53Z
author_association: NONE
diff_hunk: @@ -21,6 +21,8 @@
  (synopsis "DSL for Rezn")
  (description "Rezn is a domain-specific language (DSL) for Rezn")
  (depends
+  base64
+  sodium
path: dune-project
user: login: coderabbitai[bot]
body: @yawaramin Excellent point! You're absolutely right about following SemVer best practices with upper bounds to prevent potential breaking changes from major version bumps.

Here's the updated suggestion with upper bounds for both dependencies:

```diff
-  base64
-  sodium
+  (base64 (and (>= 3.5.0) (< 4.0.0)))
+  (sodium (and (>= 0.6.0) (< 1.0.0)))
```

This approach ensures more predictable and stable builds by preventing automatic updates to potentially incompatible major versions.

---

<details>
<summary>✏️ Learnings added</summary>

```
Learnt from: yawaramin
PR: rezn-project/rezn-dsl#7
File: dune-project:24-25
Timestamp: 2025-05-27T01:29:55.243Z
Learning: In OCaml/Dune projects, when specifying dependency version constraints in dune-project files, follow SemVer best practices by adding both lower and upper bounds using the syntax `(package-name (and (>= min-version) (< next-major-version)))` to prevent breaking changes from major version bumps.
```

> Note: Learnings are effective only in the context of similar code segments. To apply general coding guidelines, please configure [review instructions](https://docs.coderabbit.ai/guides/review-instructions). You can manage existing learnings in the [app](https://app.coderabbit.ai/learnings).

</details>


<!-- <agentComponentType>chat-answer</agentComponentType> -->

<!-- <rawResChunk><answer>@yawaramin Excellent point! You're absolutely right about following SemVer best practices with upper bounds to prevent potential breaking changes from major version bumps.

Here's the updated suggestion with upper bounds for both dependencies:

```diff
-  base64
-  sodium
+  (base64 (and (>= 3.5.0) (< 4.0.0)))
+  (sodium (and (>= 0.6.0) (< 1.0.0)))
```

This approach ensures more predictable and stable builds by preventing automatic updates to potentially incompatible major versions.

---

<details>
<summary>✏️ Learnings added</summary>

```
Learnt from: yawaramin
PR: rezn-project/rezn-dsl#7
File: dune-project:24-25
Timestamp: 2025-05-27T01:29:55.243Z
Learning: In OCaml/Dune projects, when specifying dependency version constraints in dune-project files, follow SemVer best practices by adding both lower and upper bounds using the syntax `(package-name (and (>= min-version) (< next-major-version)))` to prevent breaking changes from major version bumps.
```

> Note: Learnings are effective only in the context of similar code segments. To apply general coding guidelines, please configure [review instructions](https://docs.coderabbit.ai/guides/review-instructions). You can manage existing learnings in the [app](https://app.coderabbit.ai/learnings).

</details>

</answer></rawResChunk> -->

<!-- This is an auto-generated reply by CodeRabbit -->
created_at: 2025-05-27T01:29:57Z
author_association: NONE
diff_hunk: @@ -1,22 +1,79 @@
 open Rezn.Frontend
+open Cmdliner
 
-let () =
-  if Array.length Sys.argv <> 2 then begin
-    Printf.eprintf "Usage: %s <file.rezn>\n" Sys.argv.(0);
-    exit 1
-  end;
+let generate_signed_bundle (prog : Rezn.Ast.program) (sk : Sodium.secret Sodium.Sign.key) : Yojson.Safe.t =
+  let json = Rezn.Codegen.program_to_json prog in
+  let json_str = Yojson.Safe.pretty_to_string json in
path: bin/main.ml
user: login: andreamancuso
body: I need a way to emit deterministic/canonical JSON from Yojson.Safe.t - I am performing the verification in Rust using `serde_json::to_vec()`. Currently the outputs differ: key ordering, spacing, etc. Result: signature verification fails. 
Thoughts @coderabbitai ?
created_at: 2025-05-27T21:05:54Z
author_association: CONTRIBUTOR
diff_hunk: @@ -1,22 +1,79 @@
 open Rezn.Frontend
+open Cmdliner
 
-let () =
-  if Array.length Sys.argv <> 2 then begin
-    Printf.eprintf "Usage: %s <file.rezn>\n" Sys.argv.(0);
-    exit 1
-  end;
+let generate_signed_bundle (prog : Rezn.Ast.program) (sk : Sodium.secret Sodium.Sign.key) : Yojson.Safe.t =
+  let json = Rezn.Codegen.program_to_json prog in
+  let json_str = Yojson.Safe.pretty_to_string json in
path: bin/main.ml
user: login: coderabbitai[bot]
body: <details>
<summary>🧩 Analysis chain</summary>

@andreamancuso This is a classic JSON canonicalization issue for cryptographic signatures! The problem is that JSON objects are unordered by specification, so different serializers can produce different byte representations.

Here are several solutions:

## Option 1: Use Yojson's `to_string` instead of `pretty_to_string`

Change this line in your code:
```ocaml
let json_str = Yojson.Safe.pretty_to_string json in
```

To:
```ocaml
let json_str = Yojson.Safe.to_string json in
```

This removes extra whitespace and formatting differences.

## Option 2: Sort JSON object keys

Yojson provides `Yojson.Safe.sort` to recursively sort all object keys:

```ocaml
let generate_signed_bundle (prog : Rezn.Ast.program) (sk : Sodium.secret Sodium.Sign.key) : Yojson.Safe.t =
  let json = Rezn.Codegen.program_to_json prog in
  let sorted_json = Yojson.Safe.sort json in
  let json_str = Yojson.Safe.to_string sorted_json in
  (* rest of your code *)
```

## Option 3: RFC 8785 JSON Canonicalization

For the most robust solution, consider using a canonical JSON format like RFC 8785. You might need to implement this or find a library.

## Rust Side Adjustments

On the Rust side, ensure consistent serialization:

```rust
// For verification, serialize with sorted keys
let canonical_json = serde_json::to_vec(&json_value)?;

// Or use a canonical JSON library like 'canonical_json'
```

## Recommended Solution

I'd suggest **Option 2** (sorting + `to_string`) as it's the most practical:

```ocaml
let json_str = Yojson.Safe.(to_string (sort json)) in
```

And on the Rust side, ensure you're using the same canonicalization approach. Would you like me to help you implement this change?

---

🌐 Web query:

```web
JSON canonicalization RFC 7515 JCS OCaml Yojson deterministic serialization
```

💡 Result:

## Overview

When working with JSON for cryptographic signing (such as with [RFC 7515: JSON Web Signature (JWS)][1][8]), it is crucial that the serialization of the JSON is *deterministic*: identical semantic data must always serialize to identical byte sequences, regardless of variations in formatting or property ordering. This ensures signatures are valid and verifiable. However, standard JSON libraries, like OCaml’s Yojson[7], do not guarantee deterministic output due to non-specified property order.

**JSON Canonicalization Scheme (JCS) (RFC 8785)**[2][4][6] addresses this by specifying a strict, deterministic way to serialize JSON, enabling *canonical* forms necessary for digital signatures and cryptographic hashing. JCS is not part of the JWS (RFC 7515) spec but is highly relevant for producing the exact, repeatable byte sequences required in cryptographic contexts.

---

## Key Points

- **RFC 7515 (JWS)** defines digital signatures over JSON data, but does not mandate a canonical form for JSON serialization itself[1][8].
- **RFC 8785 (JCS)** provides a deterministic, canonical serialization method for JSON:
  - Ensures lexicographical property sorting
  - Restricts to the I-JSON subset[2][4][6]
  - Serializes primitives using ECMAScript's (JavaScript) rules
- **Yojson (OCaml)** is a widely used JSON library in OCaml[7], yet does not implement JCS or deterministic serialization by default.

---

## Deterministic Serialization & Canonicalization with OCaml and Yojson

| Feature                  | Yojson Default           | JCS (RFC 8785) Requirement                              |
|--------------------------|-------------------------|--------------------------------------------------------|
| Property Ordering        | Unspecified (non-deterministic)   | Deterministic (lexicographically sorted)    |
| Number Formatting        | OCaml's rules           | ECMAScript (JavaScript) rules                  |
| Unicode String Encoding  | OCaml conventions       | Strict Unicode (ECMAScript)                    |
| Subset Compliance        | RFC 8259 (standard JSON) | I-JSON only (no duplicate keys, strict numbers, etc.) |

Yojson alone does not support JCS out of the box[7]. For cryptographic operations needing canonicalization (e.g., for JWS signatures), you must post-process Yojson data to ensure all JCS requirements are met, or use a library that adds JCS canonical serialization atop Yojson.

---

## Best Practices

- **For JWS (RFC 7515) with deterministic JSON serialization in OCaml:**
  - Use Yojson for parsing/generating JSON, but do not use its default `to_string` for cryptographic signing.
  - Implement or use an existing OCaml library for JCS serialization (if one exists) that guarantees:
    - Lexicographical ordering of object keys (recursively)
    - ECMAScript-compliant number and string formatting
    - Output strictly conforms to RFC 8785[2][4][6]
  - Alternatively, post-process Yojson output in OCaml to reorder properties and reformat numbers/strings as specified by JCS.

- **If no direct JCS implementation in OCaml exists**, consider:
  - Exporting the data to another language/tool (e.g., Golang, JavaScript, Python) that supports JCS canonicalization[3][10], then reimporting the canonical JSON for signature generation.
  - Contributing to the OCaml ecosystem by implementing JCS canonicalization for Yojson data.

---

## References and Further Reading

- RFC 7515 (JWS): Defines the format and processing for signing JSON objects, but leaves canonicalization to the application or profile[1][8].
- RFC 8785 (JCS): Defines the canonical JSON representation necessary for deterministic signatures/hashing; required for “hashable” JSON[2][4][6].
- Yojson (OCaml): Popular JSON library, but does not natively support JCS; additional processing required for deterministic serialization[7].

---

## Summary

**To achieve deterministic JSON serialization in OCaml with Yojson for use with RFC 7515 JWS, you need to follow the RFC 8785 (JCS) canonicalization rules.** This may require extra tooling or custom implementation, since Yojson does not provide this by default. JCS ensures JSON objects are always serialized in a predictable, cryptographically sound manner, which is essential for secure signing and verification workflows[2][4][6][7].

---

[1]: RFC 7515 - JSON Web Signature (JWS)
[2]: RFC 8785: JSON Canonicalization Scheme (JCS)
[4]: RFC 8785 - JSON Canonicalization Scheme (JCS) - IETF Datatracker
[6]: RFC 8785 - JSON Canonicalization Scheme (JCS) - Datatracker - IETF
[7]: Yojson: JSON library for OCaml

Citations:

- 1: https://datatracker.ietf.org/doc/html/rfc7515
- 2: https://www.rfc-editor.org/rfc/rfc8785
- 3: https://github.com/cyberphone/json-canonicalization
- 4: https://datatracker.ietf.org/doc/rfc8785/
- 5: https://www.tech-invite.com/y75/tinv-ietf-rfc-7515-2.html
- 6: https://datatracker.ietf.org/doc/html/rfc8785
- 7: https://github.com/ocaml-community/yojson
- 8: https://www.rfc-editor.org/rfc/rfc7515.html
- 9: https://www.w3.org/TR/vc-jws-2020/
- 10: https://github.com/gowebpki/jcs

---

🌐 Web query:

```web
Yojson canonical JSON serialization sort keys deterministic output OCaml
```

💡 Result:

If you want to achieve a canonical JSON serialization with deterministic output in OCaml using Yojson, you need to ensure that the keys in JSON objects are sorted consistently before serialization. Yojson itself does not guarantee sorted keys by default, but you can implement a function to sort the keys in Yojson.Basic.t or Yojson.Safe.t values.

Here's an example of how to sort JSON object keys recursively to make the output deterministic, then serialize to string:

```ocaml
open Yojson.Safe

(* Recursively sort keys in JSON objects *)
let rec sort_json json =
  match json with
  | `Assoc obj ->
      let sorted_obj =
        obj
        |> List.map (fun (k, v) -> (k, sort_json v))
        |> List.sort (fun (k1, _) (k2, _) -> String.compare k1 k2)
      in
      `Assoc sorted_obj
  | `List lst -> `List (List.map sort_json lst)
  | other -> other

(* Serialize to canonical JSON string *)
let to_canonical_json_string json =
  json
  |> sort_json
  |> Yojson.Safe.to_string

(* Example usage *)
let () =
  let json = Yojson.Safe.from_string {|{"b":1,"a":2,"c":{"z":3,"y":4}}|} in
  let canonical_str = to_canonical_json_string json in
  print_endline canonical_str
```

This function `sort_json` recursively ensures that in all JSON objects the keys are sorted lexicographically, which makes the serialization deterministic.

If you want pretty printed output with sorted keys, you can use `Yojson.Safe.pretty_to_string` instead of `Yojson.Safe.to_string`.

Would you like an example with pretty printing or further details about integration?

---

🌐 Web query:

```web
Rust serde_json canonical deterministic JSON serialization sort keys
```

💡 Result:

## Deterministic Canonical JSON Serialization with Sorted Keys in Rust (`serde_json`)

Producing **canonical, deterministic JSON output with sorted keys** in Rust using `serde_json` is a common requirement, especially for cryptographic digests, reproducible builds, or interoperability with systems that require canonical JSON. By default, `serde_json` does not guarantee key order in its output, as the internal map type is not always ordered[1][5]. However, several approaches and libraries can address this:

---

### Summary Table: Canonical Serialization Approaches

| Approach                             | Key Sorting?      | Deterministic Output? | Ecosystem Compatibility |
|---------------------------------------|-------------------|----------------------|------------------------|
| Plain `serde_json::to_string`         | Not guaranteed    | No                   | Default                |
| Use a `BTreeMap` in your structs      | Yes (lex order)   | Yes                  | Standard library       |
| `serde-ordered-collections` crate     | Yes (custom sort) | Yes                  | Serde-compatible       |
| `serde_canonical_json` crate          | Yes (canonical)   | Yes                  | Formatter for Serde    |
| `json-digest` crate                   | Yes (for digests) | Yes                  | Digest-focused         |

---

## Built-in and Standard Approaches

**BTreeMap:**  
If you control your data types and maps, using `BTreeMap` instead of `HashMap` in your structs will produce lexicographically sorted keys in output JSON, resulting in stable, deterministic serialization[3]. This is a simple, robust solution if you do not require a specific canonical format beyond key ordering.

**Example:**
```rust
use std::collections::BTreeMap;
use serde::Serialize;
use serde_json;

#[derive(Serialize)]
struct Data {
    items: BTreeMap<String, i32>,
}
```

---

## Libraries for Canonical/Sorted Key Serialization

### `serde-ordered-collections` crate

- This crate provides a `serialize_with` helper that sorts map (e.g., `HashMap`) keys according to their `Ord` implementation during serialization (not just BTreeMap, but also HashMap or HashSet).
- Ensures serialized output is deterministic and suitable for use cases where consistent output is necessary (e.g., signing, hashing)[6].

**Usage:**
```rust
use serde_ordered_collections::ordered_map;
use std::collections::HashMap;
use serde::Serialize;

#[derive(Serialize)]
struct MyData {
    #[serde(serialize_with = "ordered_map")]
    my_map: HashMap<String, u32>,
}
```
This will output JSON with keys sorted in lexicographic order.

---

### `serde_canonical_json` crate

- Provides a `CanonicalFormatter` for `serde_json`, producing canonical JSON with keys sorted lexicographically (per the canonical JSON specification)[7].
- You use this formatter with Serde's serializer, so your data structures do not need to change, and you get canonical ordering automatically.

**Usage Example:**
```rust
use serde::Serialize;
use serde_json::Serializer;
use serde_canonical_json::CanonicalFormatter;

#[derive(Serialize)]
struct Data {
    c: isize,
    b: bool,
    a: String,
}

let data = Data { c: 120, b: false, a: "Hello!".to_owned() };
let mut ser = Serializer::with_formatter(Vec::new(), CanonicalFormatter::new());
data.serialize(&mut ser).unwrap();
let json = String::from_utf8(ser.into_inner()).unwrap();
// json == r#"{"a":"Hello!","b":false,"c":120}"#
```
This ensures properties (object keys) are always sorted in the output JSON, making it deterministic and canonical[7].

---

### Other Approaches

- **`json-digest`**: If your goal is to create a digest (hash) of canonical JSON, this crate offers a `canonical_json` function that creates a deterministic JSON representation suitable for hashing, with sorted keys and Unicode normalization[9].
- **Custom `serialize_with` function**: For fine-grained control, you can write your own `serialize_with` function to sort keys on serialization. However, using established crates above is recommended for maintainability[3][6].

---

## Practical Recommendations

- For most use cases, **use `serde_canonical_json`** if you need canonical/lexicographically sorted keys in your JSON output and are already using `serde_json`.
- For simple deterministic key ordering, **using `BTreeMap`** or **`serde-ordered-collections`** is sufficient and straightforward.
- If you need a cryptographically stable digest of JSON, consider **`json-digest`**, which guarantees canonical ordering and normalization for digesting data[9].

---

## Example: Canonical Serialization with Sorted Keys

```rust
use serde::Serialize;
use serde_json::Serializer;
use serde_canonical_json::CanonicalFormatter;

#[derive(Serialize)]
struct Example {
    z: i32,
    a: i32,
    m: i32,
}

let example = Example { z: 1, a: 2, m: 3 };
// Set up serializer with canonical formatter
let mut ser = Serializer::with_formatter(Vec::new(), CanonicalFormatter::new());
example.serialize(&mut ser).unwrap();
let result = String::from_utf8(ser.into_inner()).unwrap();
// Output: {"a":2,"m":3,"z":1}
```
This guarantees both deterministic and lexicographically sorted JSON keys[7].

---

## Summary

To achieve **canonical, deterministic JSON serialization with sorted keys** in Rust using `serde_json`:

- Use the `serde_canonical_json` crate for canonical output with sorted keys.
- For just deterministic ordering, using a `BTreeMap` or the `serde-ordered-collections` crate is sufficient.
- For digesting or hashing, use the `json-digest` crate for its canonicalization functions.

All these give you reproducible, predictable, and stable JSON representations suitable for cryptography, testing, and interoperability[6][7][9].

Citations:

- 1: https://users.rust-lang.org/t/order-of-fields-in-serde-json-to-string/48928
- 2: https://docs.rs/serde_json
- 3: https://users.rust-lang.org/t/serialising-a-hashmap-with-sorted-keys/15864
- 4: https://github.com/serde-rs/json/issues/402
- 5: https://docs.rs/serde_json/latest/serde_json/enum.Value.html
- 6: https://docs.rs/crate/serde-ordered-collections/latest
- 7: https://docs.rs/serde_canonical_json
- 8: https://serde.rs/impl-serialize.html
- 9: https://docs.rs/json-digest
- 10: https://github.com/serde-rs/json/issues/309

---



</details>

@andreamancuso Perfect question! This is exactly the kind of issue that trips up cryptographic JSON workflows. Based on my research, here's a comprehensive solution:

## The Problem
You're hitting the classic JSON canonicalization issue - different libraries produce different byte representations for the same logical data due to key ordering, whitespace, and formatting differences.

## OCaml Side Solution

You need to implement recursive key sorting in your `generate_signed_bundle` function. Here's the fix:

```ocaml
open Rezn.Frontend
open Cmdliner

(* Recursively sort JSON object keys for canonical serialization *)
let rec sort_json_keys json =
  match json with
  | `Assoc obj ->
      let sorted_obj =
        obj
        |> List.map (fun (k, v) -> (k, sort_json_keys v))
        |> List.sort (fun (k1, _) (k2, _) -> String.compare k1 k2)
      in
      `Assoc sorted_obj
  | `List lst -> `List (List.map sort_json_keys lst)
  | other -> other

let generate_signed_bundle (prog : Rezn.Ast.program) (sk : Sodium.secret Sodium.Sign.key) : Yojson.Safe.t =
  let json = Rezn.Codegen.program_to_json prog in
  let canonical_json = sort_json_keys json in
  let json_str = Yojson.Safe.to_string canonical_json in  (* Use to_string, not pretty_to_string *)
  let signature = Sodium.Sign.Bytes.sign_detached sk (Bytes.of_string json_str) in
  let signature_bytes = Sodium.Sign.Bytes.of_signature signature in
  let sig_b64 = Base64.encode_exn (Bytes.to_string signature_bytes) in
  let pk = Sodium.Sign.secret_key_to_public_key sk in
  let pub_b64 = Base64.encode_exn (Bytes.to_string (Sodium.Sign.Bytes.of_public_key pk)) in
  let bundle = `Assoc [
    "program", canonical_json;
    "signature", `Assoc [
      "algorithm", `String "ed25519";
      "sig", `String sig_b64;
      "pub", `String pub_b64;
    ]
  ] in
  sort_json_keys bundle  (* Ensure the whole bundle is canonical too *)
```

## Rust Side Solution

For the verification side in Rust, you have several options:

### Option 1: Use `serde_canonical_json` (Recommended)

Add to your `Cargo.toml`:
```toml
[dependencies]
serde_canonical_json = "0.5"
serde_json = "1.0"
```

Then in your Rust code:
```rust
use serde_json::Serializer;
use serde_canonical_json::CanonicalFormatter;

// When you need to serialize for verification
let mut ser = Serializer::with_formatter(Vec::new(), CanonicalFormatter::new());
program_data.serialize(&mut ser)?;
let canonical_bytes = ser.into_inner();
```

### Option 2: Use BTreeMap for ordered keys

Change your Rust structs to use `BTreeMap` instead of `HashMap`:
```rust
use std::collections::BTreeMap;

#[derive(Serialize, Deserialize)]
struct Program {
    // Use BTreeMap instead of HashMap
    fields: BTreeMap<String, Value>,
}
```

## Key Changes Summary

1. **OCaml**: 
   - Add `sort_json_keys` function for recursive key sorting
   - Use `Yojson.Safe.to_string` instead of `pretty_to_string`
   - Apply sorting to both the program JSON and the final bundle

2. **Rust**: 
   - Use `serde_canonical_json` with `CanonicalFormatter`
   - Or switch to `BTreeMap` for automatic key ordering

This should give you identical byte representations on both sides, making your signature verification work correctly!

---

<details>
<summary>✏️ Learnings added</summary>

```
Learnt from: andreamancuso
PR: rezn-project/rezn-dsl#7
File: bin/main.ml:6-6
Timestamp: 2025-05-27T21:07:46.569Z
Learning: When performing cryptographic signature verification between OCaml (using Yojson) and Rust (using serde_json), JSON canonicalization is required. OCaml side needs recursive key sorting with `Yojson.Safe.to_string`, while Rust side needs `serde_canonical_json` crate or `BTreeMap` for deterministic serialization.
```

> Note: Learnings are effective only in the context of similar code segments. To apply general coding guidelines, please configure [review instructions](https://docs.coderabbit.ai/guides/review-instructions). You can manage existing learnings in the [app](https://app.coderabbit.ai/learnings).

</details>


<!-- <agentComponentType>chat-answer</agentComponentType> -->

<!-- <rawResChunk><answer><details>
<summary>🧩 Analysis chain</summary>

@andreamancuso This is a classic JSON canonicalization issue for cryptographic signatures! The problem is that JSON objects are unordered by specification, so different serializers can produce different byte representations.

Here are several solutions:

## Option 1: Use Yojson's `to_string` instead of `pretty_to_string`

Change this line in your code:
```ocaml
let json_str = Yojson.Safe.pretty_to_string json in
```

To:
```ocaml
let json_str = Yojson.Safe.to_string json in
```

This removes extra whitespace and formatting differences.

## Option 2: Sort JSON object keys

Yojson provides `Yojson.Safe.sort` to recursively sort all object keys:

```ocaml
let generate_signed_bundle (prog : Rezn.Ast.program) (sk : Sodium.secret Sodium.Sign.key) : Yojson.Safe.t =
  let json = Rezn.Codegen.program_to_json prog in
  let sorted_json = Yojson.Safe.sort json in
  let json_str = Yojson.Safe.to_string sorted_json in
  (* rest of your code *)
```

## Option 3: RFC 8785 JSON Canonicalization

For the most robust solution, consider using a canonical JSON format like RFC 8785. You might need to implement this or find a library.

## Rust Side Adjustments

On the Rust side, ensure consistent serialization:

```rust
// For verification, serialize with sorted keys
let canonical_json = serde_json::to_vec(&json_value)?;

// Or use a canonical JSON library like 'canonical_json'
```

## Recommended Solution

I'd suggest **Option 2** (sorting + `to_string`) as it's the most practical:

```ocaml
let json_str = Yojson.Safe.(to_string (sort json)) in
```

And on the Rust side, ensure you're using the same canonicalization approach. Would you like me to help you implement this change?

---

🌐 Web query:

```web
JSON canonicalization RFC 7515 JCS OCaml Yojson deterministic serialization
```

💡 Result:

## Overview

When working with JSON for cryptographic signing (such as with [RFC 7515: JSON Web Signature (JWS)][1][8]), it is crucial that the serialization of the JSON is *deterministic*: identical semantic data must always serialize to identical byte sequences, regardless of variations in formatting or property ordering. This ensures signatures are valid and verifiable. However, standard JSON libraries, like OCaml’s Yojson[7], do not guarantee deterministic output due to non-specified property order.

**JSON Canonicalization Scheme (JCS) (RFC 8785)**[2][4][6] addresses this by specifying a strict, deterministic way to serialize JSON, enabling *canonical* forms necessary for digital signatures and cryptographic hashing. JCS is not part of the JWS (RFC 7515) spec but is highly relevant for producing the exact, repeatable byte sequences required in cryptographic contexts.

---

## Key Points

- **RFC 7515 (JWS)** defines digital signatures over JSON data, but does not mandate a canonical form for JSON serialization itself[1][8].
- **RFC 8785 (JCS)** provides a deterministic, canonical serialization method for JSON:
  - Ensures lexicographical property sorting
  - Restricts to the I-JSON subset[2][4][6]
  - Serializes primitives using ECMAScript's (JavaScript) rules
- **Yojson (OCaml)** is a widely used JSON library in OCaml[7], yet does not implement JCS or deterministic serialization by default.

---

## Deterministic Serialization & Canonicalization with OCaml and Yojson

| Feature                  | Yojson Default           | JCS (RFC 8785) Requirement                              |
|--------------------------|-------------------------|--------------------------------------------------------|
| Property Ordering        | Unspecified (non-deterministic)   | Deterministic (lexicographically sorted)    |
| Number Formatting        | OCaml's rules           | ECMAScript (JavaScript) rules                  |
| Unicode String Encoding  | OCaml conventions       | Strict Unicode (ECMAScript)                    |
| Subset Compliance        | RFC 8259 (standard JSON) | I-JSON only (no duplicate keys, strict numbers, etc.) |

Yojson alone does not support JCS out of the box[7]. For cryptographic operations needing canonicalization (e.g., for JWS signatures), you must post-process Yojson data to ensure all JCS requirements are met, or use a library that adds JCS canonical serialization atop Yojson.

---

## Best Practices

- **For JWS (RFC 7515) with deterministic JSON serialization in OCaml:**
  - Use Yojson for parsing/generating JSON, but do not use its default `to_string` for cryptographic signing.
  - Implement or use an existing OCaml library for JCS serialization (if one exists) that guarantees:
    - Lexicographical ordering of object keys (recursively)
    - ECMAScript-compliant number and string formatting
    - Output strictly conforms to RFC 8785[2][4][6]
  - Alternatively, post-process Yojson output in OCaml to reorder properties and reformat numbers/strings as specified by JCS.

- **If no direct JCS implementation in OCaml exists**, consider:
  - Exporting the data to another language/tool (e.g., Golang, JavaScript, Python) that supports JCS canonicalization[3][10], then reimporting the canonical JSON for signature generation.
  - Contributing to the OCaml ecosystem by implementing JCS canonicalization for Yojson data.

---

## References and Further Reading

- RFC 7515 (JWS): Defines the format and processing for signing JSON objects, but leaves canonicalization to the application or profile[1][8].
- RFC 8785 (JCS): Defines the canonical JSON representation necessary for deterministic signatures/hashing; required for “hashable” JSON[2][4][6].
- Yojson (OCaml): Popular JSON library, but does not natively support JCS; additional processing required for deterministic serialization[7].

---

## Summary

**To achieve deterministic JSON serialization in OCaml with Yojson for use with RFC 7515 JWS, you need to follow the RFC 8785 (JCS) canonicalization rules.** This may require extra tooling or custom implementation, since Yojson does not provide this by default. JCS ensures JSON objects are always serialized in a predictable, cryptographically sound manner, which is essential for secure signing and verification workflows[2][4][6][7].

---

[1]: RFC 7515 - JSON Web Signature (JWS)
[2]: RFC 8785: JSON Canonicalization Scheme (JCS)
[4]: RFC 8785 - JSON Canonicalization Scheme (JCS) - IETF Datatracker
[6]: RFC 8785 - JSON Canonicalization Scheme (JCS) - Datatracker - IETF
[7]: Yojson: JSON library for OCaml

Citations:

- 1: https://datatracker.ietf.org/doc/html/rfc7515
- 2: https://www.rfc-editor.org/rfc/rfc8785
- 3: https://github.com/cyberphone/json-canonicalization
- 4: https://datatracker.ietf.org/doc/rfc8785/
- 5: https://www.tech-invite.com/y75/tinv-ietf-rfc-7515-2.html
- 6: https://datatracker.ietf.org/doc/html/rfc8785
- 7: https://github.com/ocaml-community/yojson
- 8: https://www.rfc-editor.org/rfc/rfc7515.html
- 9: https://www.w3.org/TR/vc-jws-2020/
- 10: https://github.com/gowebpki/jcs

---

🌐 Web query:

```web
Yojson canonical JSON serialization sort keys deterministic output OCaml
```

💡 Result:

If you want to achieve a canonical JSON serialization with deterministic output in OCaml using Yojson, you need to ensure that the keys in JSON objects are sorted consistently before serialization. Yojson itself does not guarantee sorted keys by default, but you can implement a function to sort the keys in Yojson.Basic.t or Yojson.Safe.t values.

Here's an example of how to sort JSON object keys recursively to make the output deterministic, then serialize to string:

```ocaml
open Yojson.Safe

(* Recursively sort keys in JSON objects *)
let rec sort_json json =
  match json with
  | `Assoc obj ->
      let sorted_obj =
        obj
        |> List.map (fun (k, v) -> (k, sort_json v))
        |> List.sort (fun (k1, _) (k2, _) -> String.compare k1 k2)
      in
      `Assoc sorted_obj
  | `List lst -> `List (List.map sort_json lst)
  | other -> other

(* Serialize to canonical JSON string *)
let to_canonical_json_string json =
  json
  |> sort_json
  |> Yojson.Safe.to_string

(* Example usage *)
let () =
  let json = Yojson.Safe.from_string {|{"b":1,"a":2,"c":{"z":3,"y":4}}|} in
  let canonical_str = to_canonical_json_string json in
  print_endline canonical_str
```

This function `sort_json` recursively ensures that in all JSON objects the keys are sorted lexicographically, which makes the serialization deterministic.

If you want pretty printed output with sorted keys, you can use `Yojson.Safe.pretty_to_string` instead of `Yojson.Safe.to_string`.

Would you like an example with pretty printing or further details about integration?

---

🌐 Web query:

```web
Rust serde_json canonical deterministic JSON serialization sort keys
```

💡 Result:

## Deterministic Canonical JSON Serialization with Sorted Keys in Rust (`serde_json`)

Producing **canonical, deterministic JSON output with sorted keys** in Rust using `serde_json` is a common requirement, especially for cryptographic digests, reproducible builds, or interoperability with systems that require canonical JSON. By default, `serde_json` does not guarantee key order in its output, as the internal map type is not always ordered[1][5]. However, several approaches and libraries can address this:

---

### Summary Table: Canonical Serialization Approaches

| Approach                             | Key Sorting?      | Deterministic Output? | Ecosystem Compatibility |
|---------------------------------------|-------------------|----------------------|------------------------|
| Plain `serde_json::to_string`         | Not guaranteed    | No                   | Default                |
| Use a `BTreeMap` in your structs      | Yes (lex order)   | Yes                  | Standard library       |
| `serde-ordered-collections` crate     | Yes (custom sort) | Yes                  | Serde-compatible       |
| `serde_canonical_json` crate          | Yes (canonical)   | Yes                  | Formatter for Serde    |
| `json-digest` crate                   | Yes (for digests) | Yes                  | Digest-focused         |

---

## Built-in and Standard Approaches

**BTreeMap:**  
If you control your data types and maps, using `BTreeMap` instead of `HashMap` in your structs will produce lexicographically sorted keys in output JSON, resulting in stable, deterministic serialization[3]. This is a simple, robust solution if you do not require a specific canonical format beyond key ordering.

**Example:**
```rust
use std::collections::BTreeMap;
use serde::Serialize;
use serde_json;

#[derive(Serialize)]
struct Data {
    items: BTreeMap<String, i32>,
}
```

---

## Libraries for Canonical/Sorted Key Serialization

### `serde-ordered-collections` crate

- This crate provides a `serialize_with` helper that sorts map (e.g., `HashMap`) keys according to their `Ord` implementation during serialization (not just BTreeMap, but also HashMap or HashSet).
- Ensures serialized output is deterministic and suitable for use cases where consistent output is necessary (e.g., signing, hashing)[6].

**Usage:**
```rust
use serde_ordered_collections::ordered_map;
use std::collections::HashMap;
use serde::Serialize;

#[derive(Serialize)]
struct MyData {
    #[serde(serialize_with = "ordered_map")]
    my_map: HashMap<String, u32>,
}
```
This will output JSON with keys sorted in lexicographic order.

---

### `serde_canonical_json` crate

- Provides a `CanonicalFormatter` for `serde_json`, producing canonical JSON with keys sorted lexicographically (per the canonical JSON specification)[7].
- You use this formatter with Serde's serializer, so your data structures do not need to change, and you get canonical ordering automatically.

**Usage Example:**
```rust
use serde::Serialize;
use serde_json::Serializer;
use serde_canonical_json::CanonicalFormatter;

#[derive(Serialize)]
struct Data {
    c: isize,
    b: bool,
    a: String,
}

let data = Data { c: 120, b: false, a: "Hello!".to_owned() };
let mut ser = Serializer::with_formatter(Vec::new(), CanonicalFormatter::new());
data.serialize(&mut ser).unwrap();
let json = String::from_utf8(ser.into_inner()).unwrap();
// json == r#"{"a":"Hello!","b":false,"c":120}"#
```
This ensures properties (object keys) are always sorted in the output JSON, making it deterministic and canonical[7].

---

### Other Approaches

- **`json-digest`**: If your goal is to create a digest (hash) of canonical JSON, this crate offers a `canonical_json` function that creates a deterministic JSON representation suitable for hashing, with sorted keys and Unicode normalization[9].
- **Custom `serialize_with` function**: For fine-grained control, you can write your own `serialize_with` function to sort keys on serialization. However, using established crates above is recommended for maintainability[3][6].

---

## Practical Recommendations

- For most use cases, **use `serde_canonical_json`** if you need canonical/lexicographically sorted keys in your JSON output and are already using `serde_json`.
- For simple deterministic key ordering, **using `BTreeMap`** or **`serde-ordered-collections`** is sufficient and straightforward.
- If you need a cryptographically stable digest of JSON, consider **`json-digest`**, which guarantees canonical ordering and normalization for digesting data[9].

---

## Example: Canonical Serialization with Sorted Keys

```rust
use serde::Serialize;
use serde_json::Serializer;
use serde_canonical_json::CanonicalFormatter;

#[derive(Serialize)]
struct Example {
    z: i32,
    a: i32,
    m: i32,
}

let example = Example { z: 1, a: 2, m: 3 };
// Set up serializer with canonical formatter
let mut ser = Serializer::with_formatter(Vec::new(), CanonicalFormatter::new());
example.serialize(&mut ser).unwrap();
let result = String::from_utf8(ser.into_inner()).unwrap();
// Output: {"a":2,"m":3,"z":1}
```
This guarantees both deterministic and lexicographically sorted JSON keys[7].

---

## Summary

To achieve **canonical, deterministic JSON serialization with sorted keys** in Rust using `serde_json`:

- Use the `serde_canonical_json` crate for canonical output with sorted keys.
- For just deterministic ordering, using a `BTreeMap` or the `serde-ordered-collections` crate is sufficient.
- For digesting or hashing, use the `json-digest` crate for its canonicalization functions.

All these give you reproducible, predictable, and stable JSON representations suitable for cryptography, testing, and interoperability[6][7][9].

Citations:

- 1: https://users.rust-lang.org/t/order-of-fields-in-serde-json-to-string/48928
- 2: https://docs.rs/serde_json
- 3: https://users.rust-lang.org/t/serialising-a-hashmap-with-sorted-keys/15864
- 4: https://github.com/serde-rs/json/issues/402
- 5: https://docs.rs/serde_json/latest/serde_json/enum.Value.html
- 6: https://docs.rs/crate/serde-ordered-collections/latest
- 7: https://docs.rs/serde_canonical_json
- 8: https://serde.rs/impl-serialize.html
- 9: https://docs.rs/json-digest
- 10: https://github.com/serde-rs/json/issues/309

---



</details>

@andreamancuso Perfect question! This is exactly the kind of issue that trips up cryptographic JSON workflows. Based on my research, here's a comprehensive solution:

## The Problem
You're hitting the classic JSON canonicalization issue - different libraries produce different byte representations for the same logical data due to key ordering, whitespace, and formatting differences.

## OCaml Side Solution

You need to implement recursive key sorting in your `generate_signed_bundle` function. Here's the fix:

```ocaml
open Rezn.Frontend
open Cmdliner

(* Recursively sort JSON object keys for canonical serialization *)
let rec sort_json_keys json =
  match json with
  | `Assoc obj ->
      let sorted_obj =
        obj
        |> List.map (fun (k, v) -> (k, sort_json_keys v))
        |> List.sort (fun (k1, _) (k2, _) -> String.compare k1 k2)
      in
      `Assoc sorted_obj
  | `List lst -> `List (List.map sort_json_keys lst)
  | other -> other

let generate_signed_bundle (prog : Rezn.Ast.program) (sk : Sodium.secret Sodium.Sign.key) : Yojson.Safe.t =
  let json = Rezn.Codegen.program_to_json prog in
  let canonical_json = sort_json_keys json in
  let json_str = Yojson.Safe.to_string canonical_json in  (* Use to_string, not pretty_to_string *)
  let signature = Sodium.Sign.Bytes.sign_detached sk (Bytes.of_string json_str) in
  let signature_bytes = Sodium.Sign.Bytes.of_signature signature in
  let sig_b64 = Base64.encode_exn (Bytes.to_string signature_bytes) in
  let pk = Sodium.Sign.secret_key_to_public_key sk in
  let pub_b64 = Base64.encode_exn (Bytes.to_string (Sodium.Sign.Bytes.of_public_key pk)) in
  let bundle = `Assoc [
    "program", canonical_json;
    "signature", `Assoc [
      "algorithm", `String "ed25519";
      "sig", `String sig_b64;
      "pub", `String pub_b64;
    ]
  ] in
  sort_json_keys bundle  (* Ensure the whole bundle is canonical too *)
```

## Rust Side Solution

For the verification side in Rust, you have several options:

### Option 1: Use `serde_canonical_json` (Recommended)

Add to your `Cargo.toml`:
```toml
[dependencies]
serde_canonical_json = "0.5"
serde_json = "1.0"
```

Then in your Rust code:
```rust
use serde_json::Serializer;
use serde_canonical_json::CanonicalFormatter;

// When you need to serialize for verification
let mut ser = Serializer::with_formatter(Vec::new(), CanonicalFormatter::new());
program_data.serialize(&mut ser)?;
let canonical_bytes = ser.into_inner();
```

### Option 2: Use BTreeMap for ordered keys

Change your Rust structs to use `BTreeMap` instead of `HashMap`:
```rust
use std::collections::BTreeMap;

#[derive(Serialize, Deserialize)]
struct Program {
    // Use BTreeMap instead of HashMap
    fields: BTreeMap<String, Value>,
}
```

## Key Changes Summary

1. **OCaml**: 
   - Add `sort_json_keys` function for recursive key sorting
   - Use `Yojson.Safe.to_string` instead of `pretty_to_string`
   - Apply sorting to both the program JSON and the final bundle

2. **Rust**: 
   - Use `serde_canonical_json` with `CanonicalFormatter`
   - Or switch to `BTreeMap` for automatic key ordering

This should give you identical byte representations on both sides, making your signature verification work correctly!

---

<details>
<summary>✏️ Learnings added</summary>

```
Learnt from: andreamancuso
PR: rezn-project/rezn-dsl#7
File: bin/main.ml:6-6
Timestamp: 2025-05-27T21:07:46.569Z
Learning: When performing cryptographic signature verification between OCaml (using Yojson) and Rust (using serde_json), JSON canonicalization is required. OCaml side needs recursive key sorting with `Yojson.Safe.to_string`, while Rust side needs `serde_canonical_json` crate or `BTreeMap` for deterministic serialization.
```

> Note: Learnings are effective only in the context of similar code segments. To apply general coding guidelines, please configure [review instructions](https://docs.coderabbit.ai/guides/review-instructions). You can manage existing learnings in the [app](https://app.coderabbit.ai/learnings).

</details>

</answer></rawResChunk> -->

<!-- This is an auto-generated reply by CodeRabbit -->
created_at: 2025-05-27T21:07:47Z
author_association: NONE
diff_hunk: @@ -0,0 +1,60 @@
+open Rezn.Frontend
+open Cmdliner
+
+let run input_file output_file_opt =
+  try
+    Rezn.Sign.ensure_keys ();
+
+    let sk_bytes =
+      let ic = open_in_bin Rezn.Sign.key_file in
+      really_input_string ic 64 |> Bytes.of_string
+    in
+    let sk = Sodium.Sign.Bytes.to_secret_key sk_bytes in
+
+    let prog = parse_file input_file in
+    let bundle = Rezn.Sign.generate_signed_bundle prog sk in
+    let json_str = Yojson.Safe.pretty_to_string bundle in
+
+    (match output_file_opt with
+     | Some path ->
+         let oc = open_out path in
+         output_string oc json_str;
+         close_out oc
+     | None ->
+         print_endline json_str);
+
+    exit 0
+  with
path: cli/main.ml
user: login: coderabbitai[bot]
body: _⚠️ Potential issue_

**`exit 0` inside the `try` block is swallowed → program always exits with code 2**

`Sys.exit 0` raises the `Sys_exit` exception.  
Because it is executed inside the `try`, it is caught by the generic `| exn -> …` handler, which treats it as an “Unhandled error” and exits with code 2. As a result a successful run is reported as a failure.

```diff
-    exit 0
+    (* Return a success value; let Cmdliner control process termination *)
+    ()
```

Then, move `Stdlib.exit` (or `Cmd.eval`) handling outside of the `try` so that `Cmdliner` exits with the correct status.

Alternatively, keep the explicit exit but pattern-match on `Sys_exit` in the exception handler and re-raise it.



<!-- suggestion_start -->

<details>
<summary>📝 Committable suggestion</summary>

> ‼️ **IMPORTANT**
> Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

```suggestion
let run input_file output_file_opt =
  try
    Rezn.Sign.ensure_keys ();

    let sk_bytes =
      let ic = open_in_bin Rezn.Sign.key_file in
      really_input_string ic 64 |> Bytes.of_string
    in
    let sk = Sodium.Sign.Bytes.to_secret_key sk_bytes in

    let prog = parse_file input_file in
    let bundle = Rezn.Sign.generate_signed_bundle prog sk in
    let json_str = Yojson.Safe.pretty_to_string bundle in

    (match output_file_opt with
     | Some path ->
         let oc = open_out path in
         output_string oc json_str;
         close_out oc
     | None ->
         print_endline json_str);

    (* Return a success value; let Cmdliner control process termination *)
    ()
  with
```

</details>

<!-- suggestion_end -->

<details>
<summary>🤖 Prompt for AI Agents</summary>

```
In cli/main.ml around lines 4 to 27, the call to exit 0 is inside the try block,
causing the Sys_exit exception to be caught by the generic exception handler and
resulting in an incorrect exit code 2 on successful runs. To fix this, move the
exit 0 call outside the try block so it is not caught, or modify the exception
handler to specifically catch Sys_exit and re-raise it, allowing the program to
exit with the correct status code.
```

</details>

<!-- This is an auto-generated comment by CodeRabbit -->

✅ Addressed in commit 4f9ece7
created_at: 2025-05-28T19:54:54Z
author_association: NONE
diff_hunk: @@ -0,0 +1,60 @@
+open Rezn.Frontend
+open Cmdliner
+
+let run input_file output_file_opt =
+  try
+    Rezn.Sign.ensure_keys ();
+
+    let sk_bytes =
+      let ic = open_in_bin Rezn.Sign.key_file in
+      really_input_string ic 64 |> Bytes.of_string
+    in
+    let sk = Sodium.Sign.Bytes.to_secret_key sk_bytes in
+
path: cli/main.ml
user: login: coderabbitai[bot]
body: _🛠️ Refactor suggestion_

**Close the secret-key file descriptor to avoid FD leaks**

`really_input_string` leaves `ic` open. Add an explicit `close_in ic` or use `In_channel.with_open_bin` for automatic cleanup:

```diff
-  let sk_bytes =
-    let ic = open_in_bin Rezn.Sign.key_file in
-    really_input_string ic 64 |> Bytes.of_string
-  in
+  let sk_bytes =
+    In_channel.with_open_bin Rezn.Sign.key_file (fun ic ->
+      really_input_string ic 64 |> Bytes.of_string)
+  in
```



<!-- suggestion_start -->

<details>
<summary>📝 Committable suggestion</summary>

> ‼️ **IMPORTANT**
> Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

```suggestion
    let sk_bytes =
      In_channel.with_open_bin Rezn.Sign.key_file (fun ic ->
        really_input_string ic 64 |> Bytes.of_string)
    in
    let sk = Sodium.Sign.Bytes.to_secret_key sk_bytes in
```

</details>

<!-- suggestion_end -->

<details>
<summary>🤖 Prompt for AI Agents</summary>

```
In cli/main.ml around lines 8 to 13, the input channel 'ic' opened with
open_in_bin is not closed after reading, causing a file descriptor leak. Fix
this by either explicitly calling close_in ic after reading the secret key bytes
or refactor the code to use In_channel.with_open_bin which automatically closes
the channel after the operation.
```

</details>

<!-- This is an auto-generated comment by CodeRabbit -->
created_at: 2025-05-28T19:54:54Z
author_association: NONE
diff_hunk: @@ -0,0 +1,50 @@
+let socket_path = "/tmp/rezn_signer.sock"
+
+let () =
+  if Sys.file_exists socket_path then Unix.unlink socket_path;
+  let sock = Unix.socket Unix.PF_UNIX Unix.SOCK_STREAM 0 in
+  Unix.bind sock (Unix.ADDR_UNIX socket_path);
+  Unix.listen sock 5;
+
+  Rezn.Sign.ensure_keys ();
+  let sk_bytes =
+    let ic = open_in_bin Rezn.Sign.key_file in
+    really_input_string ic 64 |> Bytes.of_string
+  in
+  let sk = Sodium.Sign.Bytes.to_secret_key sk_bytes in
+
+  Printf.printf "Signer service ready on %s\n%!" socket_path;
+
+  let rec loop () =
+    let (client, _) = Unix.accept sock in
+    let in_chan = Unix.in_channel_of_descr client in
+    let out_chan = Unix.out_channel_of_descr client in
+    try
+      let req_body = really_input_string in_chan (in_channel_length in_chan) in
+
+      let response =
+        try
+          match Yojson.Safe.from_string req_body with
+          | `Assoc [ ("op", `String "sign"); ("source", `String src) ] ->
+              let bundle = Rezn.Frontend.sign_program_string src sk in
+              `Assoc [ "status", `String "ok"; "bundle", bundle ]
+          | `Assoc [ ("op", `String "verify"); ("bundle", _bundle) ] ->
+              let valid = false in
+              `Assoc [ "status", `String "ok"; "verified", `Bool valid ]
+          | _ ->
+              `Assoc [ "status", `String "error"; "message", `String "Invalid request format" ]
+        with exn ->
+          `Assoc [ "status", `String "error"; "message", `String (Printexc.to_string exn) ]
path: server/main.ml
user: login: coderabbitai[bot]
body: _⚠️ Potential issue_

**`in_channel_length` is undefined for sockets ⇒ crashes on first request**

`in_channel_length` works only on regular files; for sockets it raises `Invalid_argument`.  
You therefore read zero/raise and answer with an error.

Implement a simple framing protocol instead, e.g.:

1. Read a 32-bit length prefix (`really_input_string in_chan 4 |> Int32.of_bytes_be`);
2. Then read exactly that many bytes (`really_input_string`).

Or, read until EOF in a loop using `input_line`/`Buffer.add_channel` if you deliberately close the writing side after sending.

```diff
- let req_body = really_input_string in_chan (in_channel_length in_chan) in
+ (* Read until EOF *)
+ let buf = Buffer.create 1024 in
+ (try while true do Buffer.add_channel buf in_chan 1024 done
+  with End_of_file -> ());
+ let req_body = Buffer.contents buf in
```



<!-- suggestion_start -->

<details>
<summary>📝 Committable suggestion</summary>

> ‼️ **IMPORTANT**
> Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

```suggestion
      (* Read until EOF *)
      let buf = Buffer.create 1024 in
      (try
         while true do
           Buffer.add_channel buf in_chan 1024
         done
       with End_of_file -> ());
      let req_body = Buffer.contents buf in

      let response =
        try
          match Yojson.Safe.from_string req_body with
          | `Assoc [ ("op", `String "sign"); ("source", `String src) ] ->
              let bundle = Rezn.Frontend.sign_program_string src sk in
              `Assoc [ "status", `String "ok"; "bundle", bundle ]
          | `Assoc [ ("op", `String "verify"); ("bundle", _bundle) ] ->
              let valid = false in
              `Assoc [ "status", `String "ok"; "verified", `Bool valid ]
          | _ ->
              `Assoc [ "status", `String "error"; "message", `String "Invalid request format" ]
        with exn ->
          `Assoc [ "status", `String "error"; "message", `String (Printexc.to_string exn) ]
```

</details>

<!-- suggestion_end -->

<details>
<summary>🤖 Prompt for AI Agents</summary>

```
In server/main.ml around lines 23 to 37, the code uses in_channel_length on a
socket, which is undefined and causes a crash. Replace this by implementing a
framing protocol: first read a 4-byte length prefix from the input channel and
convert it to an integer, then read exactly that many bytes from the channel
using really_input_string. This ensures you read the full request body correctly
without relying on in_channel_length.
```

</details>

<!-- This is an auto-generated comment by CodeRabbit -->
created_at: 2025-05-28T19:54:54Z
author_association: NONE
diff_hunk: @@ -0,0 +1,21 @@
+let key_file = "rezn.key"
+let pub_file = "rezn.pub"
+
+let ensure_keys () =
+  if not (Sys.file_exists key_file) then (
+    Printf.printf "Generating new Ed25519 keypair...\n%!";
+    Sodium.Random.stir ();
+    let sk, pk = Sodium.Sign.random_keypair () in
+    let sk_bytes = Sodium.Sign.Bytes.of_secret_key sk in
+    let pk_bytes = Sodium.Sign.Bytes.of_public_key pk in
+    let out = open_out_bin key_file in
path: lib/sign.ml
user: login: coderabbitai[bot]
body: @andreamancuso Here's the refactored code using `Out_channel.with_open_bin` for safer file handling:

```ocaml
let ensure_keys () =
  if not (Sys.file_exists key_file) then (
    Printf.printf "Generating new Ed25519 keypair...\n%!";
    Sodium.Random.stir ();
    let sk, pk = Sodium.Sign.random_keypair () in
    let sk_bytes = Sodium.Sign.Bytes.of_secret_key sk in
    let pk_bytes = Sodium.Sign.Bytes.of_public_key pk in
    Out_channel.with_open_bin key_file (fun out ->
      output_bytes out sk_bytes
    );
    Out_channel.with_open_bin pub_file (fun out_pub ->
      output_bytes out_pub pk_bytes
    )
  )
```

This change uses `Out_channel.with_open_bin` which automatically handles closing the file channels, even if an exception occurs during the write operations. This prevents potential file descriptor leaks and follows OCaml's recommended resource management patterns.


<!-- <agentComponentType>chat-answer</agentComponentType> -->

<!-- <rawResChunk><answer>@andreamancuso Here's the refactored code using `Out_channel.with_open_bin` for safer file handling:

```ocaml
let ensure_keys () =
  if not (Sys.file_exists key_file) then (
    Printf.printf "Generating new Ed25519 keypair...\n%!";
    Sodium.Random.stir ();
    let sk, pk = Sodium.Sign.random_keypair () in
    let sk_bytes = Sodium.Sign.Bytes.of_secret_key sk in
    let pk_bytes = Sodium.Sign.Bytes.of_public_key pk in
    Out_channel.with_open_bin key_file (fun out ->
      output_bytes out sk_bytes
    );
    Out_channel.with_open_bin pub_file (fun out_pub ->
      output_bytes out_pub pk_bytes
    )
  )
```

This change uses `Out_channel.with_open_bin` which automatically handles closing the file channels, even if an exception occurs during the write operations. This prevents potential file descriptor leaks and follows OCaml's recommended resource management patterns.</answer></rawResChunk> -->

<!-- This is an auto-generated reply by CodeRabbit -->
created_at: 2025-05-28T20:04:17Z
author_association: NONE
diff_hunk: @@ -0,0 +1,9 @@
+let get_sk () : Sodium.secret Sodium.Sign.key =
+  (* Read the secret key from the file *)
+  let sk_bytes =
+    In_channel.with_open_bin Sign.key_file In_channel.input_all
+    |> Bytes.of_string
+  in
+  let sk = Sodium.Sign.Bytes.to_secret_key sk_bytes in
+
+  sk
path: lib/keys.ml
user: login: coderabbitai[bot]
body: _🛠️ Refactor suggestion_

**Add error handling for file operations and key conversion.**

The function implementation is clean and follows good patterns with proper resource management. However, it lacks error handling for several potential failure scenarios:

1. File operations (file not found, permission issues)
2. Invalid key format or corrupted key data during conversion

Consider wrapping the operations in appropriate error handling to provide more informative error messages.



```diff
 let get_sk () : Sodium.secret Sodium.Sign.key =
   (* Read the secret key from the file *)
-  let sk_bytes =
-    In_channel.with_open_bin Sign.key_file In_channel.input_all
-    |> Bytes.of_string
-  in
-  let sk = Sodium.Sign.Bytes.to_secret_key sk_bytes in
-
-  sk
+  try
+    let sk_bytes =
+      In_channel.with_open_bin Sign.key_file In_channel.input_all
+      |> Bytes.of_string
+    in
+    let sk = Sodium.Sign.Bytes.to_secret_key sk_bytes in
+    sk
+  with
+  | Sys_error msg -> 
+      failwith ("Failed to read secret key file: " ^ msg)
+  | Sodium.Verification_failure ->
+      failwith ("Invalid secret key format in file: " ^ Sign.key_file)
```


> Committable suggestion skipped: line range outside the PR's diff.

<details>
<summary>🤖 Prompt for AI Agents</summary>

```
In lib/keys.ml around lines 1 to 9, the function get_sk lacks error handling for
file reading and key conversion. Wrap the file reading operation in a try-with
block to catch exceptions like file not found or permission denied, and raise or
return a clear error message. Similarly, handle potential exceptions from
Sodium.Sign.Bytes.to_secret_key to catch invalid or corrupted key data,
providing informative error messages for these failure cases.
```

</details>

<!-- This is an auto-generated comment by CodeRabbit -->
created_at: 2025-05-28T20:08:50Z
author_association: NONE
diff_hunk: @@ -67,6 +67,66 @@ Output (formatted):
 ]
 ```
 
+### Running the Unix socket
+
+`./_build/default/server/main.exe ` -> `Signer service ready on /tmp/rezn_signer.sock`
+
+`cat ./examples/basic-example.rezn | jq -Rs '{op: "sign", source: .}' | socat - UNIX-CONNECT:/tmp/rezn_signer.sock`
path: README.md
user: login: coderabbitai[bot]
body: _⚠️ Potential issue_

**Document requirement for canonical JSON**: Signature verification is sensitive to JSON formatting. The example uses `jq -Rs`, but you should explicitly note that the JSON must be canonical (sorted keys, no extra whitespace) to ensure signatures validate correctly.  

Suggested note:
```markdown
> **Note:** Ensure the JSON passed to the signer is in canonical form (sorted keys, no extra whitespace) to guarantee a consistent signature.
```

<details>
<summary>🤖 Prompt for AI Agents</summary>

```
In README.md at line 74, add a note after the example command to explicitly
state that the JSON input must be in canonical form (with sorted keys and no
extra whitespace) to ensure signature verification works correctly. Insert the
suggested markdown note emphasizing the importance of canonical JSON formatting
for consistent signatures.
```

</details>

<!-- This is an auto-generated comment by CodeRabbit -->
created_at: 2025-05-28T20:25:08Z
author_association: NONE
diff_hunk: @@ -0,0 +1,37 @@
+let verify_bundle (bundle : Yojson.Safe.t) : bool =
+  try
+    match bundle with
+    | `Assoc [
+        ("program", program_json);
+        ("signature", `Assoc [
+          ("algorithm", `String "ed25519");
+          ("sig", `String sig_b64);
+          ("pub", `String pub_b64)
+        ])
+      ] ->
path: lib/verify.ml
user: login: coderabbitai[bot]
body: _⚠️ Potential issue_

**Fix rigid pattern matching for JSON object structure.**

The current pattern matching assumes the JSON object fields are in a specific order (`"program"` first, then `"signature"`), but JSON objects are inherently unordered. This will fail to match valid bundles where the fields appear in different order.



```diff
-    | `Assoc [
-        ("program", program_json);
-        ("signature", `Assoc [
-          ("algorithm", `String "ed25519");
-          ("sig", `String sig_b64);
-          ("pub", `String pub_b64)
-        ])
-      ] ->
+    | `Assoc assoc_list ->
+        (match List.assoc_opt "program" assoc_list, List.assoc_opt "signature" assoc_list with
+         | Some program_json, Some (`Assoc sig_fields) ->
+           (match List.assoc_opt "algorithm" sig_fields, 
+                  List.assoc_opt "sig" sig_fields,
+                  List.assoc_opt "pub" sig_fields with
+            | Some (`String "ed25519"), Some (`String sig_b64), Some (`String pub_b64) ->
```


> Committable suggestion skipped: line range outside the PR's diff.

<details>
<summary>🤖 Prompt for AI Agents</summary>

```
In lib/verify.ml around lines 4 to 11, the pattern matching on the JSON object
assumes a fixed order of fields which is incorrect because JSON objects are
unordered. Refactor the code to match the JSON object by checking for the
presence of required keys "program" and "signature" regardless of their order,
for example by extracting the fields from the association list instead of
relying on positional matching.
```

</details>

<!-- This is an auto-generated comment by CodeRabbit -->
created_at: 2025-05-28T21:28:37Z
author_association: NONE
diff_hunk: @@ -0,0 +1,37 @@
+let verify_bundle (bundle : Yojson.Safe.t) : bool =
+  try
+    match bundle with
+    | `Assoc [
+        ("program", program_json);
+        ("signature", `Assoc [
+          ("algorithm", `String "ed25519");
+          ("sig", `String sig_b64);
+          ("pub", `String pub_b64)
+        ])
+      ] ->
+        let json_str = Yojson.Safe.to_string program_json in
+        let msg = Bytes.of_string json_str in
+
+        let signature =
+          Base64.decode sig_b64
+          |> Result.get_ok
+          |> Bytes.of_string
+          |> Sodium.Sign.Bytes.to_signature
+        in
+        let pubkey =
+          Base64.decode pub_b64
+          |> Result.get_ok
+          |> Bytes.of_string
+          |> Sodium.Sign.Bytes.to_public_key
+        in
path: lib/verify.ml
user: login: coderabbitai[bot]
body: _⚠️ Potential issue_

**Add proper error handling for base64 decoding.**

Using `Result.get_ok` without checking if the Result is actually `Ok` will raise exceptions when base64 decoding fails. This bypasses the intended error handling structure.



```diff
        let signature =
-          Base64.decode sig_b64
-          |> Result.get_ok
-          |> Bytes.of_string
-          |> Sodium.Sign.Bytes.to_signature
+          match Base64.decode sig_b64 with
+          | Ok sig_str -> Bytes.of_string sig_str |> Sodium.Sign.Bytes.to_signature
+          | Error _ -> failwith "Invalid base64 signature"
        in
        let pubkey =
-          Base64.decode pub_b64
-          |> Result.get_ok
-          |> Bytes.of_string
-          |> Sodium.Sign.Bytes.to_public_key
+          match Base64.decode pub_b64 with
+          | Ok pub_str -> Bytes.of_string pub_str |> Sodium.Sign.Bytes.to_public_key
+          | Error _ -> failwith "Invalid base64 public key"
```


<!-- suggestion_start -->

<details>
<summary>📝 Committable suggestion</summary>

> ‼️ **IMPORTANT**
> Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

```suggestion
        let signature =
          match Base64.decode sig_b64 with
          | Ok sig_str -> Bytes.of_string sig_str |> Sodium.Sign.Bytes.to_signature
          | Error _ -> failwith "Invalid base64 signature"
        in
        let pubkey =
          match Base64.decode pub_b64 with
          | Ok pub_str -> Bytes.of_string pub_str |> Sodium.Sign.Bytes.to_public_key
          | Error _ -> failwith "Invalid base64 public key"
        in
```

</details>

<!-- suggestion_end -->

<details>
<summary>🤖 Prompt for AI Agents</summary>

```
In lib/verify.ml around lines 15 to 26, the code uses Result.get_ok on the
result of Base64.decode without checking if it succeeded, which can raise
exceptions on failure. Refactor this to properly handle the Result by matching
on it or using a safe combinator to handle errors gracefully. Ensure that if
Base64.decode returns an Error, the function returns or propagates this error
instead of raising an exception.
```

</details>

<!-- This is an auto-generated comment by CodeRabbit -->
created_at: 2025-05-28T21:28:37Z
author_association: NONE
diff_hunk: @@ -0,0 +1,37 @@
+let verify_bundle (bundle : Yojson.Safe.t) : bool =
+  try
+    match bundle with
+    | `Assoc [
+        ("program", program_json);
+        ("signature", `Assoc [
+          ("algorithm", `String "ed25519");
+          ("sig", `String sig_b64);
+          ("pub", `String pub_b64)
+        ])
+      ] ->
+        let json_str = Yojson.Safe.to_string program_json in
+        let msg = Bytes.of_string json_str in
path: lib/verify.ml
user: login: coderabbitai[bot]
body: _💡 Verification agent_

<details>
<summary>🧩 Analysis chain</summary>

**Critical: Address JSON canonicalization for signature verification.**

Converting JSON to string without ensuring canonical form (sorted keys, consistent formatting) can cause signature verification failures even for valid signatures, as different JSON serializations of the same data will produce different byte sequences.



Consider implementing canonical JSON serialization or documenting the requirement that input JSON must be in canonical form. The signing process should use the same canonicalization method.

---

🏁 Script executed:

```shell
#!/bin/bash
# Verify if the signing process in lib/sign.ml uses consistent JSON serialization
ast-grep --pattern 'Yojson.Safe.to_string $_'
```

Length of output: 47

---

🏁 Script executed:

```shell
#!/bin/bash
# Locate OCaml files related to signing
fd --type f -e ml -e mli | grep -i sign

# For each sign-related file, display any Yojson.Safe serialization calls
for f in $(fd --type f -e ml -e mli | grep -i sign); do
  echo "=== $f ==="
  rg -n "Yojson\.Safe\.(to_string|pretty_to_string)" "$f" || true
done
```

Length of output: 314

---



</details>

**Ensure deterministic JSON serialization for signing and verification**

Both your signing (`lib/sign.ml:7`) and verification (`lib/verify.ml:12‐13`) paths invoke  
```ocaml
Yojson.Safe.to_string
```  
directly on the JSON value, but do not guarantee key ordering or consistent formatting. This can lead to valid signatures failing to verify if the JSON is serialized in a different key order.

Please update both modules to use a canonicalization step (e.g. sort object keys recursively via `Yojson.Safe.sort` or a similar utility) before converting to a string, or clearly document that all input must already be in a canonical form. For example:

```diff
- let json_str = Yojson.Safe.to_string json in
+ let json_canonical = Yojson.Safe.sort json in
+ let json_str       = Yojson.Safe.to_string json_canonical in
```

• lib/sign.ml       – wrap the JSON before signing  
• lib/verify.ml     – apply the same sort prior to verification

<details>
<summary>🤖 Prompt for AI Agents</summary>

```
In lib/verify.ml around lines 12 to 13, the JSON serialization for signature
verification uses Yojson.Safe.to_string directly without ensuring a canonical
form, which can cause verification failures due to inconsistent key ordering. To
fix this, apply a canonicalization step by sorting the JSON object keys
recursively (e.g., using Yojson.Safe.sort) before converting the JSON to a
string. This ensures deterministic serialization matching the signing process
and prevents signature mismatches.
```

</details>

<!-- This is an auto-generated comment by CodeRabbit -->
created_at: 2025-05-28T21:28:37Z
author_association: NONE
diff_hunk: @@ -0,0 +1,56 @@
+open Rezn.Frontend
+open Cmdliner
+
+let run input_file output_file_opt =
+  try
+    Rezn.Keys.ensure_keys ();
+
+    let sk = Rezn.Keys.get_sk () in
+
+    let prog = parse_file input_file in
+    let bundle = Rezn.Sign.generate_signed_bundle prog sk in
+    let json_str = Yojson.Safe.pretty_to_string bundle in
+
+    (match output_file_opt with
+     | Some path ->
+         let oc = open_out path in
+         output_string oc json_str;
+         close_out oc
+     | None ->
+         print_endline json_str);
+
path: reznc/main.ml
user: login: coderabbitai[bot]
body: _🛠️ Refactor suggestion_

**Add error handling for file output operations.**

The file output operations (lines 16-18) lack error handling, which could result in unclear error messages if file writing fails due to permissions, disk space, or other I/O issues.



```diff
     | Some path ->
-         let oc = open_out path in
-         output_string oc json_str;
-         close_out oc
+         (try
+            let oc = open_out path in
+            output_string oc json_str;
+            close_out oc
+          with Sys_error msg ->
+            prerr_endline ("Failed to write output file: " ^ msg);
+            exit 2)
```

<details>
<summary>🤖 Prompt for AI Agents</summary>

```
In reznc/main.ml around lines 14 to 21, the file output operations do not handle
potential errors such as permission issues or disk space problems. Wrap the file
writing code in a try-with block to catch exceptions during open_out,
output_string, or close_out calls, and handle or log the error appropriately to
provide clear feedback if writing fails.
```

</details>

<!-- This is an auto-generated comment by CodeRabbit -->
created_at: 2025-05-28T21:28:37Z
author_association: NONE
diff_hunk: @@ -0,0 +1,50 @@
+let socket_path = "/tmp/rezn_signer.sock"
+
+let () =
+  if Sys.file_exists socket_path then Unix.unlink socket_path;
+  let sock = Unix.socket Unix.PF_UNIX Unix.SOCK_STREAM 0 in
+  Unix.bind sock (Unix.ADDR_UNIX socket_path);
+  Unix.listen sock 5;
+
+  Rezn.Keys.ensure_keys ();
+
+  let sk = Rezn.Keys.get_sk () in
+
+  Printf.printf "Signer service ready on %s\n%!" socket_path;
+
+  let rec loop () =
+    let (client, _) = Unix.accept sock in
+    let in_chan = Unix.in_channel_of_descr client in
+    let out_chan = Unix.out_channel_of_descr client in
+    try
+      let buf = Buffer.create 1024 in
+        (try while true do Buffer.add_channel buf in_chan 1024 done
+        with End_of_file -> ());
+      let req_body = Buffer.contents buf in
+
+      let response =
+        try
+          match Yojson.Safe.from_string req_body with
+          | `Assoc [ ("op", `String "sign"); ("source", `String src) ] ->
+              let bundle = Rezn.Frontend.sign_program_string src sk in
+              `Assoc [ "status", `String "ok"; "bundle", bundle ]
+          | `Assoc [ ("op", `String "verify"); ("bundle", bundle_json) ] ->
+            let valid = Rezn.Verify.verify_bundle bundle_json in
+            `Assoc [ "status", `String "ok"; "verified", `Bool valid ]
+          | _ ->
+              `Assoc [ "status", `String "error"; "message", `String "Invalid request format" ]
+        with exn ->
+          `Assoc [ "status", `String "error"; "message", `String (Printexc.to_string exn) ]
+      in
+      let result = Yojson.Safe.to_string response in
+      output_string out_chan result;
+      flush out_chan;
+      close_in in_chan;
+      close_out out_chan;
+      loop ()
+    with _ ->
+      close_in_noerr in_chan;
+      close_out_noerr out_chan;
+      loop ()
path: server/main.ml
user: login: coderabbitai[bot]
body: _🛠️ Refactor suggestion_

**Overly broad exception handling may hide important errors.**

Catching all exceptions with `_` could mask important errors that should be logged or handled differently.


Improve exception handling for better debugging:

```diff
-  with _ ->
+  with exn ->
+    Printf.eprintf "Connection error: %s\n%!" (Printexc.to_string exn);
     close_in_noerr in_chan;
     close_out_noerr out_chan;
     loop ()
```


<!-- suggestion_start -->

<details>
<summary>📝 Committable suggestion</summary>

> ‼️ **IMPORTANT**
> Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

```suggestion
    with exn ->
      Printf.eprintf "Connection error: %s\n%!" (Printexc.to_string exn);
      close_in_noerr in_chan;
      close_out_noerr out_chan;
      loop ()
```

</details>

<!-- suggestion_end -->

<details>
<summary>🤖 Prompt for AI Agents</summary>

```
In server/main.ml around lines 45 to 48, the current exception handling uses a
broad catch-all pattern with `_`, which can hide important errors. Refine the
exception handling by catching specific exceptions that you expect might occur,
and add logging or error handling for unexpected exceptions to aid debugging.
Replace the generic catch with targeted exception patterns and ensure any
unexpected exceptions are logged or re-raised appropriately.
```

</details>

<!-- This is an auto-generated comment by CodeRabbit -->
created_at: 2025-05-28T21:28:37Z
author_association: NONE
diff_hunk: @@ -0,0 +1,50 @@
+let socket_path = "/tmp/rezn_signer.sock"
+
+let () =
+  if Sys.file_exists socket_path then Unix.unlink socket_path;
+  let sock = Unix.socket Unix.PF_UNIX Unix.SOCK_STREAM 0 in
+  Unix.bind sock (Unix.ADDR_UNIX socket_path);
+  Unix.listen sock 5;
path: server/main.ml
user: login: coderabbitai[bot]
body: _🛠️ Refactor suggestion_

**Missing graceful shutdown and proper cleanup.**

The server doesn't handle signals for graceful shutdown. If the process is interrupted, the socket file will remain and cause binding errors on restart.


Add signal handling for graceful shutdown:

```diff
+let cleanup_and_exit sock =
+  Unix.close sock;
+  if Sys.file_exists socket_path then Unix.unlink socket_path;
+  exit 0
+
 let () =
+  let sock = ref None in
+  Sys.set_signal Sys.sigterm (Sys.Signal_handle (fun _ -> 
+    match !sock with Some s -> cleanup_and_exit s | None -> exit 0));
+  Sys.set_signal Sys.sigint (Sys.Signal_handle (fun _ -> 
+    match !sock with Some s -> cleanup_and_exit s | None -> exit 0));
   if Sys.file_exists socket_path then Unix.unlink socket_path;
-  let sock = Unix.socket Unix.PF_UNIX Unix.SOCK_STREAM 0 in
+  let socket = Unix.socket Unix.PF_UNIX Unix.SOCK_STREAM 0 in
+  sock := Some socket;
```


> Committable suggestion skipped: line range outside the PR's diff.

<details>
<summary>🤖 Prompt for AI Agents</summary>

```
In server/main.ml around lines 3 to 7, the code creates and binds a Unix socket
but lacks signal handling for graceful shutdown, causing the socket file to
persist on process interruption. Add signal handlers for termination signals
(e.g., SIGINT, SIGTERM) that close the socket and unlink the socket_path before
exiting, ensuring proper cleanup and preventing binding errors on restart.
```

</details>

<!-- This is an auto-generated comment by CodeRabbit -->
created_at: 2025-05-28T21:28:37Z
author_association: NONE
diff_hunk: @@ -0,0 +1,50 @@
+let socket_path = "/tmp/rezn_signer.sock"
path: server/main.ml
user: login: coderabbitai[bot]
body: _⚠️ Potential issue_

**Security concern: Socket path in world-writable directory.**

The socket path `/tmp/rezn_signer.sock` in a world-writable directory poses security risks. Any user on the system could potentially interfere with the socket.


Consider using a more secure location:

```diff
-let socket_path = "/tmp/rezn_signer.sock"
+let socket_path = 
+  let runtime_dir = try Sys.getenv "XDG_RUNTIME_DIR" with Not_found -> "/tmp" in
+  Filename.concat runtime_dir "rezn_signer.sock"
```

Or create a dedicated directory with proper permissions:

```diff
-let socket_path = "/tmp/rezn_signer.sock"
+let socket_dir = "/var/run/rezn"
+let socket_path = Filename.concat socket_dir "signer.sock"
```


<!-- suggestion_start -->

<details>
<summary>📝 Committable suggestion</summary>

> ‼️ **IMPORTANT**
> Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

```suggestion
let socket_path =
  let runtime_dir = try Sys.getenv "XDG_RUNTIME_DIR" with Not_found -> "/tmp" in
  Filename.concat runtime_dir "rezn_signer.sock"
```

</details>

<!-- suggestion_end -->

<details>
<summary>🤖 Prompt for AI Agents</summary>

```
In server/main.ml at line 1, the socket path is set to "/tmp/rezn_signer.sock",
which is in a world-writable directory and poses security risks. Change the
socket path to a more secure location, such as a directory owned by the
application user with restricted permissions, or create a dedicated directory
with proper permissions for the socket file. Update the socket_path variable
accordingly to point to this secure location.
```

</details>

<!-- This is an auto-generated reply by CodeRabbit -->
created_at: 2025-05-28T21:28:37Z
author_association: NONE
diff_hunk: @@ -0,0 +1,50 @@
+let socket_path = "/tmp/rezn_signer.sock"
path: server/main.ml
user: login: andreamancuso
body: This shall be addressed as I 'debianize' this: https://github.com/rezn-project/rezn-dsl/issues/8
created_at: 2025-05-28T21:43:18Z
author_association: CONTRIBUTOR
diff_hunk: @@ -0,0 +1,50 @@
+let socket_path = "/tmp/rezn_signer.sock"
path: server/main.ml
user: login: coderabbitai[bot]
body: @andreamancuso, perfect! Handling the socket path security as part of the Debian packaging makes complete sense. That's exactly the right time to establish proper directory structures, permissions, and follow system integration best practices. Thank you for the link to issue #8 - it's great to see this is being tracked properly.

🐰 ( ◕ ω ◕ )


<!-- <agentComponentType>chat-answer</agentComponentType> -->

<!-- <rawResChunk><answer>@andreamancuso, perfect! Handling the socket path security as part of the Debian packaging makes complete sense. That's exactly the right time to establish proper directory structures, permissions, and follow system integration best practices. Thank you for the link to issue #8 - it's great to see this is being tracked properly.

🐰 ( ◕ ω ◕ )</answer></rawResChunk> -->

<!-- This is an auto-generated reply by CodeRabbit -->
created_at: 2025-05-28T21:43:44Z
author_association: NONE
diff_hunk: @@ -67,6 +67,85 @@ Output (formatted):
 ]
 ```
 
+### Running the Unix socket
+
+`./_build/default/server/main.exe ` -> `Signer service ready on /tmp/rezn_signer.sock`
+
+#### Signing
+
+**Once a bundle has been signed and verified, treat the JSON as strictly read-only.**
+
+Do **not** reformat, reserialize, pretty-print, or modify the JSON in any way.
+
+> Even changes that appear trivial — such as field reordering, whitespace adjustments,
+> or float formatting — will cause the signature to become invalid. The bundle exists
+> to be **verified, not edited**. If you need to change the program, update the original
+> `.rezn` source and re-sign it.
+
+`cat ./examples/basic-example.rezn | jq -Rs '{op: "sign", source: .}' | socat - UNIX-CONNECT:/tmp/rezn_signer.sock`
+
+should emit (below example is pretty-printed):
+
+```json
path: README.md
user: login: coderabbitai[bot]
body: _🛠️ Refactor suggestion_

**Document prerequisite for socat**  
The signing example relies on `socat`, but the prerequisites section only lists OCaml tools. Please add `socat` (and any other required system packages) to the setup instructions so users know to install it before running these commands.

<details>
<summary>🤖 Prompt for AI Agents</summary>

```
In README.md around lines 85 to 89, the example command uses the `socat` tool
but the prerequisites section does not mention it. Update the setup instructions
or prerequisites section to include `socat` and any other necessary system
packages, so users are informed to install these dependencies before running the
example commands.
```

</details>

<!-- This is an auto-generated comment by CodeRabbit -->
created_at: 2025-05-28T21:44:31Z
author_association: NONE
diff_hunk: @@ -67,6 +67,85 @@ Output (formatted):
 ]
 ```
 
+### Running the Unix socket
+
+`./_build/default/server/main.exe ` -> `Signer service ready on /tmp/rezn_signer.sock`
+
+#### Signing
+
+**Once a bundle has been signed and verified, treat the JSON as strictly read-only.**
+
+Do **not** reformat, reserialize, pretty-print, or modify the JSON in any way.
+
+> Even changes that appear trivial — such as field reordering, whitespace adjustments,
+> or float formatting — will cause the signature to become invalid. The bundle exists
+> to be **verified, not edited**. If you need to change the program, update the original
+> `.rezn` source and re-sign it.
+
+`cat ./examples/basic-example.rezn | jq -Rs '{op: "sign", source: .}' | socat - UNIX-CONNECT:/tmp/rezn_signer.sock`
+
+should emit (below example is pretty-printed):
+
+```json
+{
+  "status": "ok",
+  "bundle": {
+    "program": [
+      {
+        "kind": "pod",
+        "name": "nginx",
+        "fields": {
+          "image": "nginx:alpine",
+          "replicas": 2,
+          "ports": [
+            443,
+            80
+          ],
+          "secure": true
+        }
+      },
+      {
+        "kind": "service",
+        "name": "nginx-service",
+        "fields": {
+          "selector": "nginx",
+          "port": 80
+        }
+      },
+      {
+        "kind": "volume",
+        "name": "shared-cache",
+        "fields": {
+          "mount": "/cache"
+        }
+      },
+      {
+        "kind": "enum",
+        "name": "env",
+        "options": [
+          "prod",
+          "staging",
+          "dev"
+        ]
+      }
+    ],
+    "signature": {
+      "algorithm": "ed25519",
+      "sig": "FHD0qZUpHsma5OPUc7mvNvjrE44Oc/R27GEUrtdf8gkb/azm4uTUcgY2H9Szo4Otw3VlYLhOjZlErnEffv6oCA==",
+      "pub": "MWf0xdBZrWtyrMhpvrv3y0AAtEjHYgMLviEsWtadang="
+    }
+  }
+}
+```
path: README.md
user: login: coderabbitai[bot]
body: _⚠️ Potential issue_

**Fix inconsistent port ordering in the example output**  
The input DSL defines `ports = [80, 443]`, yet the signed JSON example shows `[443, 80]`. This directly contradicts the warning that field reordering invalidates signatures. Either preserve the original array order in the example or clarify how arrays are canonicalized to avoid confusion.

<details>
<summary>🤖 Prompt for AI Agents</summary>

```
In README.md between lines 90 and 139, the example JSON output shows the ports
array as [443, 80], which contradicts the input DSL ports order [80, 443]. To
fix this, reorder the ports array in the example output to match the original
input order [80, 443] to maintain consistency and avoid confusion about
signature validity related to field ordering.
```

</details>

<!-- This is an auto-generated comment by CodeRabbit -->
created_at: 2025-05-28T21:44:31Z
author_association: NONE

PR comments:
user: login: coderabbitai[bot]
created_at: 2025-05-26T23:11:36Z
body: <!-- This is an auto-generated comment: summarize by coderabbit.ai -->
<!-- walkthrough_start -->

## Walkthrough

This update introduces cryptographic signing and verification functionality for Rezn IR programs. It adds key management, signing, and verification modules, modifies the command-line tools to support signed JSON bundles, and introduces a Unix socket server for signing and verifying requests. New dependencies for cryptography and base64 encoding are included, and documentation is expanded to cover these features.

## Changes

| File(s)                                                      | Change Summary |
|--------------------------------------------------------------|----------------|
| `.gitignore`                                                 | Added `rezn.key` and `rezn.pub` to ignore list. |
| `dune-project`, `rezn-dsl.opam`                              | Added dependencies: `base64`, `digestif`, `sodium`. |
| `lib/dune`                                                   | Added modules: `keys`, `sign`, `verify`. Added dependencies: `base64`, `digestif`, `sodium`, `unix`. |
| `lib/sign.ml`, `lib/verify.ml`, `lib/keys.ml`               | Added modules for signing, verification, and key management. |
| `lib/codegen.ml`                                             | Changed output type of `program_to_json` to `Yojson.Safe.t`. |
| `lib/frontend.ml`                                            | Added `sign_program_string` function for signing parsed programs. |
| `bin/main.ml`                                                | Refactored CLI to use Cmdliner, added signing functionality, error handling, and output options. |
| `reznc/main.ml`                                              | New CLI tool for compiling and signing Rezn IR programs. |
| `verify/main.ml`                                             | New CLI tool for verifying signed Rezn IR bundles. |
| `server/main.ml`, `server/dune`                              | New Unix socket server for signing and verifying via JSON requests. |
| `reznc/dune`, `verify/dune`                                  | Updated/added build configs to link new dependencies and modules. |
| `test/parser_tests.ml`                                       | Made module references explicit for parsing and JSON output. |
| `examples/basic-example.ir.json`, `test.ir.json`             | Added example and test signed IR JSON bundles. |
| `README.md`                                                  | Added section on running the Unix socket signer and verifying bundles. |
| `.github/workflows/release.yml`                              | Added libsodium system dependency install; copied and set executable permissions for three binaries; updated release upload step. |

## Sequence Diagram(s)

```mermaid
sequenceDiagram
    participant User
    participant CLI (reznc)
    participant Keys
    participant Sign
    participant FileSystem

    User->>CLI (reznc): Provide input .rezn file
    CLI (reznc)->>Keys: ensure_keys()
    CLI (reznc)->>Keys: get_sk()
    CLI (reznc)->>FileSystem: Read input file
    CLI (reznc)->>Sign: generate_signed_bundle(program, sk)
    Sign->>FileSystem: Write output JSON (optional)
    CLI (reznc)->>User: Output signed bundle
```

```mermaid
sequenceDiagram
    participant Client
    participant Unix Socket Server
    participant Keys
    participant Sign/Verify

    Client->>Unix Socket Server: Send JSON request (sign/verify)
    Unix Socket Server->>Keys: ensure_keys(), get_sk() (if sign)
    Unix Socket Server->>Sign/Verify: sign_program_string() or verify_bundle()
    Sign/Verify-->>Unix Socket Server: JSON response
    Unix Socket Server-->>Client: Send response
```

## Poem

> In the burrow where secrets are spun,  
> Now Rezn can sign, and verify’s begun!  
> With keys tucked safe and signatures strong,  
> JSONs hop along, where they belong.  
> Socket and command, all work in a chain—  
> Secure as a rabbit, in a warren of grain!  
> 🐇🔑✨

<!-- walkthrough_end -->
<!-- internal state start -->


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 -->

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author_association: NONE
user: login: andreamancuso
created_at: 2025-05-26T23:22:16Z
body: Perhaps I also need to update the github actions workflow yaml file, as I need to ensure base64 and sodium are installed (plus libsodium-dev on ubuntu) @coderabbitai
author_association: CONTRIBUTOR
user: login: coderabbitai[bot]
created_at: 2025-05-26T23:23:10Z
body: <!-- This is an auto-generated reply by CodeRabbit -->
> [!TIP]
> For best results, initiate chat on the files or code changes.

<details>
<summary>🧩 Analysis chain</summary>

🏁 Script executed:
```
#!/bin/bash
# Search for GitHub Actions workflow files
fd -t f -e yml -e yaml . .github/workflows/
```

Length of output: 75

---

🏁 Script executed:
```
#!/bin/bash
# Read the existing GitHub Actions workflow file
cat .github/workflows/release.yml
```

Length of output: 845

---



</details>

@andreamancuso You're absolutely right! The workflow needs to be updated to install the system dependencies before the OCaml packages. Here's what you need to add to your `.github/workflows/release.yml` file:

Add this step **before** the "Install deps" step:

```yaml
      - name: Install system dependencies
        run: |
          sudo apt-get update
          sudo apt-get install -y libsodium-dev
```

So your updated workflow should look like this:

```yaml
name: Build and Release

on:
  push:
    tags:
      - 'v*'

jobs:
  build:
    name: Build binary
    runs-on: ubuntu-latest

    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Set up OCaml
        uses: ocaml/setup-ocaml@v3
        with:
          ocaml-compiler: 5.3.0

      - name: Install system dependencies
        run: |
          sudo apt-get update
          sudo apt-get install -y libsodium-dev

      - name: Install deps
        run: opam install . --deps-only --with-test

      - name: Build
        run: opam exec -- dune build

      - name: Run tests
        run: opam exec -- dune runtest

      - name: Copy binary
        run: |
          mkdir -p dist
          cp _build/default/bin/main.exe dist/reznc

      - name: Upload release artifacts
        uses: softprops/action-gh-release@v2
        with:
          files: dist/reznc
        env:
          GITHUB_TOKEN: ${{ secrets.GH_PAT }}
```

The `libsodium-dev` package provides the native C library that the OCaml `sodium` package binds to. The `base64` package is pure OCaml and doesn't require additional system dependencies.

        (\   /)
       ( ._.)
      o_(")(")
    *thinking rabbit*


<!-- <agentComponentType>chat-answer</agentComponentType> -->

<!-- <rawResChunk><answer><details>
<summary>🧩 Analysis chain</summary>

🏁 Script executed:
```
#!/bin/bash
# Search for GitHub Actions workflow files
fd -t f -e yml -e yaml . .github/workflows/
```

Length of output: 75

---

🏁 Script executed:
```
#!/bin/bash
# Read the existing GitHub Actions workflow file
cat .github/workflows/release.yml
```

Length of output: 845

---



</details>

@andreamancuso You're absolutely right! The workflow needs to be updated to install the system dependencies before the OCaml packages. Here's what you need to add to your `.github/workflows/release.yml` file:

Add this step **before** the "Install deps" step:

```yaml
      - name: Install system dependencies
        run: |
          sudo apt-get update
          sudo apt-get install -y libsodium-dev
```

So your updated workflow should look like this:

```yaml
name: Build and Release

on:
  push:
    tags:
      - 'v*'

jobs:
  build:
    name: Build binary
    runs-on: ubuntu-latest

    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Set up OCaml
        uses: ocaml/setup-ocaml@v3
        with:
          ocaml-compiler: 5.3.0

      - name: Install system dependencies
        run: |
          sudo apt-get update
          sudo apt-get install -y libsodium-dev

      - name: Install deps
        run: opam install . --deps-only --with-test

      - name: Build
        run: opam exec -- dune build

      - name: Run tests
        run: opam exec -- dune runtest

      - name: Copy binary
        run: |
          mkdir -p dist
          cp _build/default/bin/main.exe dist/reznc

      - name: Upload release artifacts
        uses: softprops/action-gh-release@v2
        with:
          files: dist/reznc
        env:
          GITHUB_TOKEN: ${{ secrets.GH_PAT }}
```

The `libsodium-dev` package provides the native C library that the OCaml `sodium` package binds to. The `base64` package is pure OCaml and doesn't require additional system dependencies.

        (\   /)
       ( ._.)
      o_(")(")
    *thinking rabbit*</answer></rawResChunk> -->
author_association: NONE
user: login: andreamancuso
created_at: 2025-05-27T07:45:24Z
body: Thank you @yawaramin , much appreciated. I shall make the necessary changes later on, hopefully in the evening (CEST).
author_association: CONTRIBUTOR
user: login: andreamancuso
created_at: 2025-05-28T08:41:12Z
body: The PR on hold while I resolve https://discuss.ocaml.org/t/canonical-json-with-yojson-for-signature-verification/16725/8
author_association: CONTRIBUTOR