Repository: lettre/lettre (language: rust)

Issue:
RUSTSEC-2025-0007: *ring* is unmaintained

> *ring* is unmaintained

| Details             |                                                |
| ------------------- | ---------------------------------------------- |
| Status              | unmaintained                |
| Package             | `ring`                      |
| Version             | `0.17.10`                   |
| URL                 | [https://github.com/briansmith/ring/discussions/2414](https://github.com/briansmith/ring/discussions/2414) |
| Date                | 2025-02-20                         |

The author has announced an indefinite hiatus in its development, noting that
any reported security vulnerabilities may go unaddressed for prolonged periods
of time.

See [advisory page](https://rustsec.org/advisories/RUSTSEC-2025-0007.html) for additional details.



Discussion / hints:

Fix patch:
diff --git a/Cargo.lock b/Cargo.lock
index c28e41fa2..f14c9048e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -241,6 +241,47 @@ version = "1.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ace50bade8e6234aa140d9a2f552bbee1db4d353f69b8217bc503490fc1a9f26"
 
+[[package]]
+name = "aws-lc-fips-sys"
+version = "0.13.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "29003a681b2b9465c1139bfb726da452a841a8b025f35953f3bce71139f10b21"
+dependencies = [
+ "bindgen 0.69.5",
+ "cc",
+ "cmake",
+ "dunce",
+ "fs_extra",
+ "paste",
+ "regex",
+]
+
+[[package]]
+name = "aws-lc-rs"
+version = "1.12.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4cd755adf9707cf671e31d944a189be3deaaeee11c8bc1d669bb8022ac90fbd0"
+dependencies = [
+ "aws-lc-fips-sys",
+ "aws-lc-sys",
+ "paste",
+ "zeroize",
+]
+
+[[package]]
+name = "aws-lc-sys"
+version = "0.26.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0f9dd2e03ee80ca2822dd6ea431163d2ef259f2066a4d6ccaca6d9dcb386aa43"
+dependencies = [
+ "bindgen 0.69.5",
+ "cc",
+ "cmake",
+ "dunce",
+ "fs_extra",
+ "paste",
+]
+
 [[package]]
 name = "backtrace"
 version = "0.3.74"
@@ -268,6 +309,29 @@ version = "1.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8c3c1a368f70d6cf7302d78f8f7093da241fb8e8807c05cc9e51a125895a6d5b"
 
+[[package]]
+name = "bindgen"
+version = "0.69.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "271383c67ccabffb7381723dea0672a673f292304fcb45c01cc648c7a8d58088"
+dependencies = [
+ "bitflags",
+ "cexpr",
+ "clang-sys",
+ "itertools 0.10.5",
+ "lazy_static",
+ "lazycell",
+ "log",
+ "prettyplease",
+ "proc-macro2",
+ "quote",
+ "regex",
+ "rustc-hash",
+ "shlex",
+ "syn 2.0.89",
+ "which",
+]
+
 [[package]]
 name = "bindgen"
 version = "0.70.1"
@@ -335,7 +399,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "777cf31ea10f7eb87d46b30848f8d7acbd65cb4a25cd51bee1808ef601de0416"
 dependencies = [
  "autocfg",
- "bindgen",
+ "bindgen 0.70.1",
  "cmake",
  "fs_extra",
  "fslock",
@@ -371,6 +435,8 @@ version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fd9de9f2205d5ef3fd67e685b0df337994ddd4495e2a28d185500d0e1edfea47"
 dependencies = [
+ "jobserver",
+ "libc",
  "shlex",
 ]
 
@@ -664,6 +730,12 @@ dependencies = [
  "syn 2.0.89",
 ]
 
+[[package]]
+name = "dunce"
+version = "1.0.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "92773504d58c093f6de2459af4af33faa518c13451eb8f2b5698ed3d36e7c813"
+
 [[package]]
 name = "ed25519"
 version = "2.2.3"
@@ -969,6 +1041,15 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fbf6a919d6cf397374f7dfeeea91d974c7c0a7221d0d0f4f20d859d329e53fcc"
 
+[[package]]
+name = "home"
+version = "0.5.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e3d1354bf6b7235cb4a0576c2619fd4ed18183f689b12b006a0ee7329eeff9a5"
+dependencies = [
+ "windows-sys 0.52.0",
+]
+
 [[package]]
 name = "hostname"
 version = "0.4.0"
@@ -1160,6 +1241,15 @@ version = "1.0.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d75a2a4b1b190afb6f5425f10f6a8f959d2ea0b9c2b1d79553551850539e4674"
 
+[[package]]
+name = "jobserver"
+version = "0.1.32"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "48d1dbcbbeb6a7fec7e059840aa538bd62aaccf972c7346c4d9d2059312853d0"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "js-sys"
 version = "0.3.72"
@@ -1187,6 +1277,12 @@ dependencies = [
  "spin",
 ]
 
+[[package]]
+name = "lazycell"
+version = "1.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "830d08ce1d1d941e6b30645f1a0eb5643013d835ce3779a5fc208261dbe10f55"
+
 [[package]]
 name = "lettre"
 version = "0.11.13"
@@ -1509,6 +1605,12 @@ version = "2.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f38d5652c16fde515bb1ecef450ab0f6a219d619a7274976324d5e377f7dceba"
 
+[[package]]
+name = "paste"
+version = "1.0.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "57c0d7b74b563b49d38dae00a0c37d4d6de9b432382b2892f0574ddcae73fd0a"
+
 [[package]]
 name = "pem-rfc7468"
 version = "0.7.0"
@@ -1636,6 +1738,16 @@ dependencies = [
  "yansi",
 ]
 
+[[package]]
+name = "prettyplease"
+version = "0.2.25"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "64d1ec885c64d0457d564db4ec299b2dae3f9c02808b8ad9c3a089c591b18033"
+dependencies = [
+ "proc-macro2",
+ "syn 2.0.89",
+]
+
 [[package]]
 name = "proc-macro-error"
 version = "1.0.4"
@@ -1845,6 +1957,7 @@ version = "0.23.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9c9cc1d47e243d655ace55ed38201c19ae02c148ae56412ab8750e8f0166ab7f"
 dependencies = [
+ "aws-lc-rs",
  "log",
  "once_cell",
  "ring",
@@ -1878,6 +1991,7 @@ version = "0.102.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "64ca1bc8749bd4cf37b5ce386cc146580777b4e8572c7b97baf22c83f444bee9"
 dependencies = [
+ "aws-lc-rs",
  "ring",
  "rustls-pki-types",
  "untrusted",
@@ -2460,6 +2574,18 @@ dependencies = [
  "rustls-pki-types",
 ]
 
+[[package]]
+name = "which"
+version = "4.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "87ba24419a2078cd2b0f2ede2691b6c66d8e47836da3b6db8265ebad47afbfc7"
+dependencies = [
+ "either",
+ "home",
+ "once_cell",
+ "rustix",
+]
+
 [[package]]
 name = "winapi"
 version = "0.3.9"
diff --git a/Cargo.toml b/Cargo.toml
index d724fb622..4cddf4f69 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -48,7 +48,7 @@ percent-encoding = { version = "2.3", optional = true }
 
 ## tls
 native-tls = { version = "0.2.9", optional = true } # feature
-rustls = { version = "0.23.5", default-features = false, features = ["ring", "logging", "std", "tls12"], optional = true }
+rustls = { version = "0.23.5", default-features = false, features = ["logging", "std", "tls12"], optional = true }
 rustls-native-certs = { version = "0.8", optional = true }
 webpki-roots = { version = "0.26", optional = true }
 boring = { version = "4", optional = true }
@@ -60,12 +60,12 @@ async-trait = { version = "0.1", optional = true }
 
 ## async-std
 async-std = { version = "1.8", optional = true }
-futures-rustls = { version = "0.26", default-features = false, features = ["logging", "tls12", "ring"], optional = true }
+futures-rustls = { version = "0.26", default-features = false, features = ["logging", "tls12"], optional = true }
 
 ## tokio
 tokio1_crate = { package = "tokio", version = "1", optional = true }
 tokio1_native_tls_crate = { package = "tokio-native-tls", version = "0.3", optional = true }
-tokio1_rustls = { package = "tokio-rustls", version = "0.26", default-features = false, features = ["logging", "tls12", "ring"], optional = true }
+tokio1_rustls = { package = "tokio-rustls", version = "0.26", default-features = false, features = ["logging", "tls12"], optional = true }
 tokio1_boring = { package = "tokio-boring", version = "4", optional = true }
 
 ## dkim
@@ -109,16 +109,26 @@ smtp-transport = ["dep:base64", "dep:nom", "dep:socket2", "dep:url", "dep:percen
 
 pool = ["dep:futures-util"]
 
-rustls-tls = ["dep:webpki-roots", "dep:rustls"]
+rustls = ["dep:rustls"]
+aws-lc-rs = ["rustls?/aws-lc-rs"]
+fips = ["aws-lc-rs", "rustls?/fips"]
+ring = ["rustls?/ring"]
+webpki-roots = ["dep:webpki-roots"]
+# deprecated
+rustls-tls = ["webpki-roots", "rustls", "ring"]
 
 boring-tls = ["dep:boring"]
 
 # async
 async-std1 = ["dep:async-std", "dep:async-trait", "dep:futures-io", "dep:futures-util"]
-async-std1-rustls-tls = ["async-std1", "rustls-tls", "dep:futures-rustls"]
+async-std1-rustls = ["async-std1", "rustls", "dep:futures-rustls"]
+# deprecated
+async-std1-rustls-tls = ["async-std1-rustls", "rustls-tls"]
 tokio1 = ["dep:tokio1_crate", "dep:async-trait", "dep:futures-io", "dep:futures-util"]
 tokio1-native-tls = ["tokio1", "native-tls", "dep:tokio1_native_tls_crate"]
-tokio1-rustls-tls = ["tokio1", "rustls-tls", "dep:tokio1_rustls"]
+tokio1-rustls = ["tokio1", "rustls", "dep:tokio1_rustls"]
+# deprecated
+tokio1-rustls-tls = ["tokio1-rustls", "rustls-tls"]
 tokio1-boring-tls = ["tokio1", "boring-tls", "dep:tokio1_boring"]
 
 dkim = ["dep:base64", "dep:sha2", "dep:rsa", "dep:ed25519-dalek"]
diff --git a/src/executor.rs b/src/executor.rs
index d698cb2af..f221d5eee 100644
--- a/src/executor.rs
+++ b/src/executor.rs
@@ -133,7 +133,7 @@ impl Executor for Tokio1Executor {
     ) -> Result<AsyncSmtpConnection, Error> {
         #[allow(clippy::match_single_binding)]
         let tls_parameters = match tls {
-            #[cfg(any(feature = "tokio1-native-tls", feature = "tokio1-rustls-tls"))]
+            #[cfg(any(feature = "tokio1-native-tls", feature = "tokio1-rustls"))]
             Tls::Wrapper(tls_parameters) => Some(tls_parameters.clone()),
             _ => None,
         };
@@ -147,7 +147,7 @@ impl Executor for Tokio1Executor {
         )
         .await?;
 
-        #[cfg(any(feature = "tokio1-native-tls", feature = "tokio1-rustls-tls"))]
+        #[cfg(any(feature = "tokio1-native-tls", feature = "tokio1-rustls"))]
         match tls {
             Tls::Opportunistic(tls_parameters) => {
                 if conn.can_starttls() {
@@ -230,7 +230,7 @@ impl Executor for AsyncStd1Executor {
     ) -> Result<AsyncSmtpConnection, Error> {
         #[allow(clippy::match_single_binding)]
         let tls_parameters = match tls {
-            #[cfg(feature = "async-std1-rustls-tls")]
+            #[cfg(feature = "async-std1-rustls")]
             Tls::Wrapper(tls_parameters) => Some(tls_parameters.clone()),
             _ => None,
         };
@@ -243,7 +243,7 @@ impl Executor for AsyncStd1Executor {
         )
         .await?;
 
-        #[cfg(feature = "async-std1-rustls-tls")]
+        #[cfg(feature = "async-std1-rustls")]
         match tls {
             Tls::Opportunistic(tls_parameters) => {
                 if conn.can_starttls() {
diff --git a/src/lib.rs b/src/lib.rs
index 648db8b4a..3ac796712 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -64,13 +64,46 @@
 //!
 //! #### SMTP over TLS via the rustls crate
 //!
-//! _Secure SMTP connections using TLS from the `rustls-tls` crate_
+//! _Secure SMTP connections using TLS from the `rustls` crate_
 //!
-//! Rustls uses [ring] as the cryptography implementation. As a result, [not all Rust's targets are supported][ring-support].
+//! * **rustls**: TLS support for the synchronous version of the API
+//! * **tokio1-rustls**: TLS support for the `tokio1` async version of the API
+//! * **async-std1-rustls**: TLS support for the `async-std1` async version of the API
 //!
-//! * **rustls-tls**: TLS support for the synchronous version of the API
-//! * **tokio1-rustls-tls**: TLS support for the `tokio1` async version of the API
-//! * **async-std1-rustls-tls**: TLS support for the `async-std1` async version of the API
+//! ##### rustls crypto backends
+//!
+//! _The crypto implementation to use with rustls_
+//!
+//! When the `rustls` feature is enabled, one of the following crypto backends MUST also
+//! be enabled.
+//!
+//! * **aws-lc-rs**: use [AWS-LC] (via [`aws-lc-rs`]) as the `rustls` crypto backend
+//! * **ring**: use [`ring`] as the `rustls` crypto backend
+//!
+//! When enabling `aws-lc-rs`, the `fips` feature can also be enabled to have
+//! rustls use the FIPS certified module of AWS-LC.
+//!
+//! `aws-lc-rs` may require cmake on some platforms to compile.
+//! `fips` always requires cmake and the Go compiler to compile.
+//!
+//! ##### rustls certificate verification backend
+//!
+//! _The TLS certificate verification backend to use with rustls_
+//!
+//! When the `rustls` feature is enabled, one of the following verification backends
+//! MUST also be enabled.
+//!
+//! * **rustls-native-certs**: verify TLS certificates using the platform's native certificate store (see [`rustls-native-certs`])
+//! * **webpki-roots**: verify TLS certificates against Mozilla's root certificates (see [`webpki-roots`])
+//!
+//! For the `rustls-native-certs` backend to work correctly, the following packages
+//! will need to be installed in order for the build stage and the compiled program
+//! to run properly.
+//!
+//! | Distro       | Build-time packages        | Runtime packages             |
+//! | ------------ | -------------------------- | ---------------------------- |
+//! | Debian       | none                       | `ca-certificates`            |
+//! | Alpine Linux | none                       | `ca-certificates`            |
 //!
 //! ### Sendmail transport
 //!
@@ -115,8 +148,11 @@
 //! [`ContentType`]: crate::message::header::ContentType
 //! [tokio]: https://docs.rs/tokio/1
 //! [async-std]: https://docs.rs/async-std/1
-//! [ring]: https://github.com/briansmith/ring#ring
-//! [ring-support]: https://github.com/briansmith/ring#online-automated-testing
+//! [AWS-LC]: https://github.com/aws/aws-lc
+//! [`aws-lc-rs`]: https://crates.io/crates/aws-lc-rs
+//! [`ring`]: https://crates.io/crates/ring
+//! [`rustls-native-certs`]: https://crates.io/crates/rustls-native-certs
+//! [`webpki-roots`]: https://crates.io/crates/webpki-roots
 //! [Tokio 1.x]: https://docs.rs/tokio/1
 //! [async-std 1.x]: https://docs.rs/async-std/1
 //! [mime 0.3]: https://docs.rs/mime/0.3
@@ -163,6 +199,22 @@
 
 #[cfg(not(lettre_ignore_tls_mismatch))]
 mod compiletime_checks {
+    #[cfg(all(feature = "rustls", not(feature = "aws-lc-rs"), not(feature = "ring")))]
+    compile_error!(
+        "feature `rustls` also requires either the `aws-lc-rs` or the `ring` feature to
+    be enabled"
+    );
+
+    #[cfg(all(
+        feature = "rustls",
+        not(feature = "rustls-native-certs"),
+        not(feature = "webpki-roots")
+    ))]
+    compile_error!(
+        "feature `rustls` also requires either the `rustls-native-certs` or the `webpki-roots` feature to
+    be enabled"
+    );
+
     #[cfg(all(feature = "native-tls", feature = "boring-tls"))]
     compile_error!("feature \"native-tls\" and feature \"boring-tls\" cannot be enabled at the same time, otherwise
     the executable will fail to link.");
@@ -173,16 +225,12 @@ mod compiletime_checks {
         not(feature = "tokio1-native-tls")
     ))]
     compile_error!("Lettre is being built with the `tokio1` and the `native-tls` features, but the `tokio1-native-tls` feature hasn't been turned on.
-    If you were trying to opt into `rustls-tls` and did not activate `native-tls`, disable the default-features of lettre in `Cargo.toml` and manually add the required features.
+    If you were trying to opt into `rustls` and did not activate `native-tls`, disable the default-features of lettre in `Cargo.toml` and manually add the required features.
     Make sure to apply the same to any of your crate dependencies that use the `lettre` crate.");
 
-    #[cfg(all(
-        feature = "tokio1",
-        feature = "rustls-tls",
-        not(feature = "tokio1-rustls-tls")
-    ))]
-    compile_error!("Lettre is being built with the `tokio1` and the `rustls-tls` features, but the `tokio1-rustls-tls` feature hasn't been turned on.
-    If you'd like to use `native-tls` make sure that the `rustls-tls` feature hasn't been enabled by mistake.
+    #[cfg(all(feature = "tokio1", feature = "rustls", not(feature = "tokio1-rustls")))]
+    compile_error!("Lettre is being built with the `tokio1` and the `rustls` features, but the `tokio1-rustls` feature hasn't been turned on.
+    If you'd like to use `native-tls` make sure that the `rustls` feature hasn't been enabled by mistake.
     Make sure to apply the same to any of your crate dependencies that use the `lettre` crate.");
 
     #[cfg(all(
@@ -191,22 +239,22 @@ mod compiletime_checks {
         not(feature = "tokio1-boring-tls")
     ))]
     compile_error!("Lettre is being built with the `tokio1` and the `boring-tls` features, but the `tokio1-boring-tls` feature hasn't been turned on.
-    If you'd like to use `boring-tls` make sure that the `rustls-tls` feature hasn't been enabled by mistake.
+    If you'd like to use `boring-tls` make sure that the `rustls` feature hasn't been enabled by mistake.
     Make sure to apply the same to any of your crate dependencies that use the `lettre` crate.");
 
-    #[cfg(all(feature = "async-std1", feature = "native-tls",))]
+    #[cfg(all(feature = "async-std1", feature = "native-tls"))]
     compile_error!("Lettre is being built with the `async-std1` and the `native-tls` features, but the async-std integration doesn't support native-tls yet.
 If you'd like to work on the issue please take a look at https://github.com/lettre/lettre/issues/576.
-If you were trying to opt into `rustls-tls` and did not activate `native-tls`, disable the default-features of lettre in `Cargo.toml` and manually add the required features.
+If you were trying to opt into `rustls` and did not activate `native-tls`, disable the default-features of lettre in `Cargo.toml` and manually add the required features.
 Make sure to apply the same to any of your crate dependencies that use the `lettre` crate.");
 
     #[cfg(all(
         feature = "async-std1",
-        feature = "rustls-tls",
-        not(feature = "async-std1-rustls-tls")
+        feature = "rustls",
+        not(feature = "async-std1-rustls")
     ))]
-    compile_error!("Lettre is being built with the `async-std1` and the `rustls-tls` features, but the `async-std1-rustls-tls` feature hasn't been turned on.
-If you'd like to use `native-tls` make sure that the `rustls-tls` hasn't been enabled by mistake.
+    compile_error!("Lettre is being built with the `async-std1` and the `rustls` features, but the `async-std1-rustls` feature hasn't been turned on.
+If you'd like to use `native-tls` make sure that the `rustls` hasn't been enabled by mistake.
 Make sure to apply the same to any of your crate dependencies that use the `lettre` crate.");
 }
 
@@ -219,6 +267,8 @@ mod executor;
 #[cfg(feature = "builder")]
 #[cfg_attr(docsrs, doc(cfg(feature = "builder")))]
 pub mod message;
+#[cfg(feature = "rustls")]
+mod rustls_crypto;
 mod time;
 pub mod transport;
 
diff --git a/src/rustls_crypto.rs b/src/rustls_crypto.rs
new file mode 100644
index 000000000..d2f1c4265
--- /dev/null
+++ b/src/rustls_crypto.rs
@@ -0,0 +1,14 @@
+use std::sync::Arc;
+
+use rustls::crypto::CryptoProvider;
+
+pub(crate) fn crypto_provider() -> Arc<CryptoProvider> {
+    CryptoProvider::get_default().cloned().unwrap_or_else(|| {
+        #[cfg(feature = "aws-lc-rs")]
+        let provider = rustls::crypto::aws_lc_rs::default_provider();
+        #[cfg(not(feature = "aws-lc-rs"))]
+        let provider = rustls::crypto::ring::default_provider();
+
+        Arc::new(provider)
+    })
+}
diff --git a/src/transport/smtp/async_transport.rs b/src/transport/smtp/async_transport.rs
index 4baebd270..e2ce51a74 100644
--- a/src/transport/smtp/async_transport.rs
+++ b/src/transport/smtp/async_transport.rs
@@ -14,8 +14,8 @@ use super::pool::async_impl::Pool;
 use super::PoolConfig;
 #[cfg(any(
     feature = "tokio1-native-tls",
-    feature = "tokio1-rustls-tls",
-    feature = "async-std1-rustls-tls"
+    feature = "tokio1-rustls",
+    feature = "async-std1-rustls"
 ))]
 use super::Tls;
 use super::{
@@ -111,15 +111,15 @@ where
     /// to validate TLS certificates.
     #[cfg(any(
         feature = "tokio1-native-tls",
-        feature = "tokio1-rustls-tls",
-        feature = "async-std1-rustls-tls"
+        feature = "tokio1-rustls",
+        feature = "async-std1-rustls"
     ))]
     #[cfg_attr(
         docsrs,
         doc(cfg(any(
             feature = "tokio1-native-tls",
-            feature = "tokio1-rustls-tls",
-            feature = "async-std1-rustls-tls"
+            feature = "tokio1-rustls",
+            feature = "async-std1-rustls"
         )))
     )]
     pub fn relay(relay: &str) -> Result<AsyncSmtpTransportBuilder, Error> {
@@ -145,15 +145,15 @@ where
     /// or emails will be sent to the server, protecting from downgrade attacks.
     #[cfg(any(
         feature = "tokio1-native-tls",
-        feature = "tokio1-rustls-tls",
-        feature = "async-std1-rustls-tls"
+        feature = "tokio1-rustls",
+        feature = "async-std1-rustls"
     ))]
     #[cfg_attr(
         docsrs,
         doc(cfg(any(
             feature = "tokio1-native-tls",
-            feature = "tokio1-rustls-tls",
-            feature = "async-std1-rustls-tls"
+            feature = "tokio1-rustls",
+            feature = "async-std1-rustls"
         )))
     )]
     pub fn starttls_relay(relay: &str) -> Result<AsyncSmtpTransportBuilder, Error> {
@@ -288,10 +288,10 @@ where
     /// # Ok(())
     /// # }
     /// ```
-    #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+    #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
     #[cfg_attr(
         docsrs,
-        doc(cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls")))
+        doc(cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls")))
     )]
     pub fn from_url(connection_url: &str) -> Result<AsyncSmtpTransportBuilder, Error> {
         super::connection_url::from_connection_url(connection_url)
@@ -416,15 +416,15 @@ impl AsyncSmtpTransportBuilder {
     /// lead to hard to debug IO errors coming from the TLS library.
     #[cfg(any(
         feature = "tokio1-native-tls",
-        feature = "tokio1-rustls-tls",
-        feature = "async-std1-rustls-tls"
+        feature = "tokio1-rustls",
+        feature = "async-std1-rustls"
     ))]
     #[cfg_attr(
         docsrs,
         doc(cfg(any(
             feature = "tokio1-native-tls",
-            feature = "tokio1-rustls-tls",
-            feature = "async-std1-rustls-tls"
+            feature = "tokio1-rustls",
+            feature = "async-std1-rustls"
         )))
     )]
     pub fn tls(mut self, tls: Tls) -> Self {
diff --git a/src/transport/smtp/client/async_connection.rs b/src/transport/smtp/client/async_connection.rs
index 576934936..3149d6f2b 100644
--- a/src/transport/smtp/client/async_connection.rs
+++ b/src/transport/smtp/client/async_connection.rs
@@ -375,7 +375,7 @@ impl AsyncSmtpConnection {
     }
 
     /// The X509 certificate of the server (DER encoded)
-    #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+    #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
     pub fn peer_certificate(&self) -> Result<Vec<u8>, Error> {
         self.stream.get_ref().peer_certificate()
     }
@@ -397,7 +397,7 @@ impl AsyncSmtpConnection {
     }
 
     /// All the X509 certificates of the chain (DER encoded)
-    #[cfg(any(feature = "rustls-tls", feature = "boring-tls"))]
+    #[cfg(any(feature = "rustls", feature = "boring-tls"))]
     pub fn certificate_chain(&self) -> Result<Vec<Vec<u8>>, Error> {
         self.stream.get_ref().certificate_chain()
     }
diff --git a/src/transport/smtp/client/async_net.rs b/src/transport/smtp/client/async_net.rs
index 2c0173f3e..47b66db9b 100644
--- a/src/transport/smtp/client/async_net.rs
+++ b/src/transport/smtp/client/async_net.rs
@@ -12,9 +12,9 @@ use futures_io::{
     AsyncRead as FuturesAsyncRead, AsyncWrite as FuturesAsyncWrite, Error as IoError, ErrorKind,
     Result as IoResult,
 };
-#[cfg(feature = "async-std1-rustls-tls")]
+#[cfg(feature = "async-std1-rustls")]
 use futures_rustls::client::TlsStream as AsyncStd1RustlsTlsStream;
-#[cfg(any(feature = "tokio1-rustls-tls", feature = "async-std1-rustls-tls"))]
+#[cfg(any(feature = "tokio1-rustls", feature = "async-std1-rustls"))]
 use rustls::pki_types::ServerName;
 #[cfg(feature = "tokio1-boring-tls")]
 use tokio1_boring::SslStream as Tokio1SslStream;
@@ -27,14 +27,14 @@ use tokio1_crate::net::{
 };
 #[cfg(feature = "tokio1-native-tls")]
 use tokio1_native_tls_crate::TlsStream as Tokio1TlsStream;
-#[cfg(feature = "tokio1-rustls-tls")]
+#[cfg(feature = "tokio1-rustls")]
 use tokio1_rustls::client::TlsStream as Tokio1RustlsTlsStream;
 
 #[cfg(any(
     feature = "tokio1-native-tls",
-    feature = "tokio1-rustls-tls",
+    feature = "tokio1-rustls",
     feature = "tokio1-boring-tls",
-    feature = "async-std1-rustls-tls"
+    feature = "async-std1-rustls"
 ))]
 use super::InnerTlsParameters;
 use super::TlsParameters;
@@ -78,7 +78,7 @@ enum InnerAsyncNetworkStream {
     #[cfg(feature = "tokio1-native-tls")]
     Tokio1NativeTls(Tokio1TlsStream<Box<dyn AsyncTokioStream>>),
     /// Encrypted Tokio 1.x TCP stream
-    #[cfg(feature = "tokio1-rustls-tls")]
+    #[cfg(feature = "tokio1-rustls")]
     Tokio1RustlsTls(Tokio1RustlsTlsStream<Box<dyn AsyncTokioStream>>),
     /// Encrypted Tokio 1.x TCP stream
     #[cfg(feature = "tokio1-boring-tls")]
@@ -87,7 +87,7 @@ enum InnerAsyncNetworkStream {
     #[cfg(feature = "async-std1")]
     AsyncStd1Tcp(AsyncStd1TcpStream),
     /// Encrypted Tokio 1.x TCP stream
-    #[cfg(feature = "async-std1-rustls-tls")]
+    #[cfg(feature = "async-std1-rustls")]
     AsyncStd1RustlsTls(AsyncStd1RustlsTlsStream<AsyncStd1TcpStream>),
     /// Can't be built
     None,
@@ -112,13 +112,13 @@ impl AsyncNetworkStream {
             InnerAsyncNetworkStream::Tokio1NativeTls(s) => {
                 s.get_ref().get_ref().get_ref().peer_addr()
             }
-            #[cfg(feature = "tokio1-rustls-tls")]
+            #[cfg(feature = "tokio1-rustls")]
             InnerAsyncNetworkStream::Tokio1RustlsTls(s) => s.get_ref().0.peer_addr(),
             #[cfg(feature = "tokio1-boring-tls")]
             InnerAsyncNetworkStream::Tokio1BoringTls(s) => s.get_ref().peer_addr(),
             #[cfg(feature = "async-std1")]
             InnerAsyncNetworkStream::AsyncStd1Tcp(s) => s.peer_addr(),
-            #[cfg(feature = "async-std1-rustls-tls")]
+            #[cfg(feature = "async-std1-rustls")]
             InnerAsyncNetworkStream::AsyncStd1RustlsTls(s) => s.get_ref().0.peer_addr(),
             InnerAsyncNetworkStream::None => {
                 debug_assert!(false, "InnerAsyncNetworkStream::None must never be built");
@@ -258,18 +258,18 @@ impl AsyncNetworkStream {
                 feature = "tokio1",
                 not(any(
                     feature = "tokio1-native-tls",
-                    feature = "tokio1-rustls-tls",
+                    feature = "tokio1-rustls",
                     feature = "tokio1-boring-tls"
                 ))
             ))]
             InnerAsyncNetworkStream::Tokio1Tcp(_) => {
                 let _ = tls_parameters;
-                panic!("Trying to upgrade an AsyncNetworkStream without having enabled either the tokio1-native-tls or the tokio1-rustls-tls feature");
+                panic!("Trying to upgrade an AsyncNetworkStream without having enabled either the tokio1-native-tls or the tokio1-rustls feature");
             }
 
             #[cfg(any(
                 feature = "tokio1-native-tls",
-                feature = "tokio1-rustls-tls",
+                feature = "tokio1-rustls",
                 feature = "tokio1-boring-tls"
             ))]
             InnerAsyncNetworkStream::Tokio1Tcp(_) => {
@@ -284,13 +284,13 @@ impl AsyncNetworkStream {
                     .map_err(error::connection)?;
                 Ok(())
             }
-            #[cfg(all(feature = "async-std1", not(feature = "async-std1-rustls-tls")))]
+            #[cfg(all(feature = "async-std1", not(feature = "async-std1-rustls")))]
             InnerAsyncNetworkStream::AsyncStd1Tcp(_) => {
                 let _ = tls_parameters;
-                panic!("Trying to upgrade an AsyncNetworkStream without having enabled the async-std1-rustls-tls feature");
+                panic!("Trying to upgrade an AsyncNetworkStream without having enabled the async-std1-rustls feature");
             }
 
-            #[cfg(feature = "async-std1-rustls-tls")]
+            #[cfg(feature = "async-std1-rustls")]
             InnerAsyncNetworkStream::AsyncStd1Tcp(_) => {
                 // get owned TcpStream
                 let tcp_stream = mem::replace(&mut self.inner, InnerAsyncNetworkStream::None);
@@ -310,7 +310,7 @@ impl AsyncNetworkStream {
     #[allow(unused_variables)]
     #[cfg(any(
         feature = "tokio1-native-tls",
-        feature = "tokio1-rustls-tls",
+        feature = "tokio1-rustls",
         feature = "tokio1-boring-tls"
     ))]
     async fn upgrade_tokio1_tls(
@@ -337,12 +337,12 @@ impl AsyncNetworkStream {
                     Ok(InnerAsyncNetworkStream::Tokio1NativeTls(stream))
                 };
             }
-            #[cfg(feature = "rustls-tls")]
+            #[cfg(feature = "rustls")]
             InnerTlsParameters::RustlsTls(config) => {
-                #[cfg(not(feature = "tokio1-rustls-tls"))]
-                panic!("built without the tokio1-rustls-tls feature");
+                #[cfg(not(feature = "tokio1-rustls"))]
+                panic!("built without the tokio1-rustls feature");
 
-                #[cfg(feature = "tokio1-rustls-tls")]
+                #[cfg(feature = "tokio1-rustls")]
                 return {
                     use tokio1_rustls::TlsConnector;
 
@@ -377,7 +377,7 @@ impl AsyncNetworkStream {
     }
 
     #[allow(unused_variables)]
-    #[cfg(feature = "async-std1-rustls-tls")]
+    #[cfg(feature = "async-std1-rustls")]
     async fn upgrade_asyncstd1_tls(
         tcp_stream: AsyncStd1TcpStream,
         mut tls_parameters: TlsParameters,
@@ -389,12 +389,12 @@ impl AsyncNetworkStream {
             InnerTlsParameters::NativeTls(connector) => {
                 panic!("native-tls isn't supported with async-std yet. See https://github.com/lettre/lettre/pull/531#issuecomment-757893531");
             }
-            #[cfg(feature = "rustls-tls")]
+            #[cfg(feature = "rustls")]
             InnerTlsParameters::RustlsTls(config) => {
-                #[cfg(not(feature = "async-std1-rustls-tls"))]
-                panic!("built without the async-std1-rustls-tls feature");
+                #[cfg(not(feature = "async-std1-rustls"))]
+                panic!("built without the async-std1-rustls feature");
 
-                #[cfg(feature = "async-std1-rustls-tls")]
+                #[cfg(feature = "async-std1-rustls")]
                 return {
                     use futures_rustls::TlsConnector;
 
@@ -422,13 +422,13 @@ impl AsyncNetworkStream {
             InnerAsyncNetworkStream::Tokio1Tcp(_) => false,
             #[cfg(feature = "tokio1-native-tls")]
             InnerAsyncNetworkStream::Tokio1NativeTls(_) => true,
-            #[cfg(feature = "tokio1-rustls-tls")]
+            #[cfg(feature = "tokio1-rustls")]
             InnerAsyncNetworkStream::Tokio1RustlsTls(_) => true,
             #[cfg(feature = "tokio1-boring-tls")]
             InnerAsyncNetworkStream::Tokio1BoringTls(_) => true,
             #[cfg(feature = "async-std1")]
             InnerAsyncNetworkStream::AsyncStd1Tcp(_) => false,
-            #[cfg(feature = "async-std1-rustls-tls")]
+            #[cfg(feature = "async-std1-rustls")]
             InnerAsyncNetworkStream::AsyncStd1RustlsTls(_) => true,
             InnerAsyncNetworkStream::None => false,
         }
@@ -443,7 +443,7 @@ impl AsyncNetworkStream {
             }
             #[cfg(feature = "tokio1-native-tls")]
             InnerAsyncNetworkStream::Tokio1NativeTls(_) => panic!("Unsupported"),
-            #[cfg(feature = "tokio1-rustls-tls")]
+            #[cfg(feature = "tokio1-rustls")]
             InnerAsyncNetworkStream::Tokio1RustlsTls(_) => panic!("Unsupported"),
             #[cfg(feature = "tokio1-boring-tls")]
             InnerAsyncNetworkStream::Tokio1BoringTls(stream) => {
@@ -453,7 +453,7 @@ impl AsyncNetworkStream {
             InnerAsyncNetworkStream::AsyncStd1Tcp(_) => {
                 Err(error::client("Connection is not encrypted"))
             }
-            #[cfg(feature = "async-std1-rustls-tls")]
+            #[cfg(feature = "async-std1-rustls")]
             InnerAsyncNetworkStream::AsyncStd1RustlsTls(_) => panic!("Unsupported"),
             InnerAsyncNetworkStream::None => panic!("InnerNetworkStream::None must never be built"),
         }
@@ -466,7 +466,7 @@ impl AsyncNetworkStream {
             }
             #[cfg(feature = "tokio1-native-tls")]
             InnerAsyncNetworkStream::Tokio1NativeTls(_) => panic!("Unsupported"),
-            #[cfg(feature = "tokio1-rustls-tls")]
+            #[cfg(feature = "tokio1-rustls")]
             InnerAsyncNetworkStream::Tokio1RustlsTls(stream) => Ok(stream
                 .get_ref()
                 .1
@@ -487,7 +487,7 @@ impl AsyncNetworkStream {
             InnerAsyncNetworkStream::AsyncStd1Tcp(_) => {
                 Err(error::client("Connection is not encrypted"))
             }
-            #[cfg(feature = "async-std1-rustls-tls")]
+            #[cfg(feature = "async-std1-rustls")]
             InnerAsyncNetworkStream::AsyncStd1RustlsTls(stream) => Ok(stream
                 .get_ref()
                 .1
@@ -514,7 +514,7 @@ impl AsyncNetworkStream {
                 .unwrap()
                 .to_der()
                 .map_err(error::tls)?),
-            #[cfg(feature = "tokio1-rustls-tls")]
+            #[cfg(feature = "tokio1-rustls")]
             InnerAsyncNetworkStream::Tokio1RustlsTls(stream) => Ok(stream
                 .get_ref()
                 .1
@@ -534,7 +534,7 @@ impl AsyncNetworkStream {
             InnerAsyncNetworkStream::AsyncStd1Tcp(_) => {
                 Err(error::client("Connection is not encrypted"))
             }
-            #[cfg(feature = "async-std1-rustls-tls")]
+            #[cfg(feature = "async-std1-rustls")]
             InnerAsyncNetworkStream::AsyncStd1RustlsTls(stream) => Ok(stream
                 .get_ref()
                 .1
@@ -574,7 +574,7 @@ impl FuturesAsyncRead for AsyncNetworkStream {
                     Poll::Pending => Poll::Pending,
                 }
             }
-            #[cfg(feature = "tokio1-rustls-tls")]
+            #[cfg(feature = "tokio1-rustls")]
             InnerAsyncNetworkStream::Tokio1RustlsTls(s) => {
                 let mut b = Tokio1ReadBuf::new(buf);
                 match Pin::new(s).poll_read(cx, &mut b) {
@@ -594,7 +594,7 @@ impl FuturesAsyncRead for AsyncNetworkStream {
             }
             #[cfg(feature = "async-std1")]
             InnerAsyncNetworkStream::AsyncStd1Tcp(s) => Pin::new(s).poll_read(cx, buf),
-            #[cfg(feature = "async-std1-rustls-tls")]
+            #[cfg(feature = "async-std1-rustls")]
             InnerAsyncNetworkStream::AsyncStd1RustlsTls(s) => Pin::new(s).poll_read(cx, buf),
             InnerAsyncNetworkStream::None => {
                 debug_assert!(false, "InnerAsyncNetworkStream::None must never be built");
@@ -616,13 +616,13 @@ impl FuturesAsyncWrite for AsyncNetworkStream {
             InnerAsyncNetworkStream::Tokio1Tcp(s) => Pin::new(s).poll_write(cx, buf),
             #[cfg(feature = "tokio1-native-tls")]
             InnerAsyncNetworkStream::Tokio1NativeTls(s) => Pin::new(s).poll_write(cx, buf),
-            #[cfg(feature = "tokio1-rustls-tls")]
+            #[cfg(feature = "tokio1-rustls")]
             InnerAsyncNetworkStream::Tokio1RustlsTls(s) => Pin::new(s).poll_write(cx, buf),
             #[cfg(feature = "tokio1-boring-tls")]
             InnerAsyncNetworkStream::Tokio1BoringTls(s) => Pin::new(s).poll_write(cx, buf),
             #[cfg(feature = "async-std1")]
             InnerAsyncNetworkStream::AsyncStd1Tcp(s) => Pin::new(s).poll_write(cx, buf),
-            #[cfg(feature = "async-std1-rustls-tls")]
+            #[cfg(feature = "async-std1-rustls")]
             InnerAsyncNetworkStream::AsyncStd1RustlsTls(s) => Pin::new(s).poll_write(cx, buf),
             InnerAsyncNetworkStream::None => {
                 debug_assert!(false, "InnerAsyncNetworkStream::None must never be built");
@@ -637,13 +637,13 @@ impl FuturesAsyncWrite for AsyncNetworkStream {
             InnerAsyncNetworkStream::Tokio1Tcp(s) => Pin::new(s).poll_flush(cx),
             #[cfg(feature = "tokio1-native-tls")]
             InnerAsyncNetworkStream::Tokio1NativeTls(s) => Pin::new(s).poll_flush(cx),
-            #[cfg(feature = "tokio1-rustls-tls")]
+            #[cfg(feature = "tokio1-rustls")]
             InnerAsyncNetworkStream::Tokio1RustlsTls(s) => Pin::new(s).poll_flush(cx),
             #[cfg(feature = "tokio1-boring-tls")]
             InnerAsyncNetworkStream::Tokio1BoringTls(s) => Pin::new(s).poll_flush(cx),
             #[cfg(feature = "async-std1")]
             InnerAsyncNetworkStream::AsyncStd1Tcp(s) => Pin::new(s).poll_flush(cx),
-            #[cfg(feature = "async-std1-rustls-tls")]
+            #[cfg(feature = "async-std1-rustls")]
             InnerAsyncNetworkStream::AsyncStd1RustlsTls(s) => Pin::new(s).poll_flush(cx),
             InnerAsyncNetworkStream::None => {
                 debug_assert!(false, "InnerAsyncNetworkStream::None must never be built");
@@ -658,13 +658,13 @@ impl FuturesAsyncWrite for AsyncNetworkStream {
             InnerAsyncNetworkStream::Tokio1Tcp(s) => Pin::new(s).poll_shutdown(cx),
             #[cfg(feature = "tokio1-native-tls")]
             InnerAsyncNetworkStream::Tokio1NativeTls(s) => Pin::new(s).poll_shutdown(cx),
-            #[cfg(feature = "tokio1-rustls-tls")]
+            #[cfg(feature = "tokio1-rustls")]
             InnerAsyncNetworkStream::Tokio1RustlsTls(s) => Pin::new(s).poll_shutdown(cx),
             #[cfg(feature = "tokio1-boring-tls")]
             InnerAsyncNetworkStream::Tokio1BoringTls(s) => Pin::new(s).poll_shutdown(cx),
             #[cfg(feature = "async-std1")]
             InnerAsyncNetworkStream::AsyncStd1Tcp(s) => Pin::new(s).poll_close(cx),
-            #[cfg(feature = "async-std1-rustls-tls")]
+            #[cfg(feature = "async-std1-rustls")]
             InnerAsyncNetworkStream::AsyncStd1RustlsTls(s) => Pin::new(s).poll_close(cx),
             InnerAsyncNetworkStream::None => {
                 debug_assert!(false, "InnerAsyncNetworkStream::None must never be built");
diff --git a/src/transport/smtp/client/connection.rs b/src/transport/smtp/client/connection.rs
index 76f778f42..659d51dca 100644
--- a/src/transport/smtp/client/connection.rs
+++ b/src/transport/smtp/client/connection.rs
@@ -143,7 +143,7 @@ impl SmtpConnection {
         hello_name: &ClientId,
     ) -> Result<(), Error> {
         if self.server_info.supports_feature(Extension::StartTls) {
-            #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+            #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
             {
                 try_smtp!(self.command(Starttls), self);
                 self.stream.get_mut().upgrade_tls(tls_parameters)?;
@@ -153,11 +153,7 @@ impl SmtpConnection {
                 try_smtp!(self.ehlo(hello_name), self);
                 Ok(())
             }
-            #[cfg(not(any(
-                feature = "native-tls",
-                feature = "rustls-tls",
-                feature = "boring-tls"
-            )))]
+            #[cfg(not(any(feature = "native-tls", feature = "rustls", feature = "boring-tls")))]
             // This should never happen as `Tls` can only be created
             // when a TLS library is enabled
             unreachable!("TLS support required but not supported");
@@ -303,7 +299,7 @@ impl SmtpConnection {
     }
 
     /// The X509 certificate of the server (DER encoded)
-    #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+    #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
     pub fn peer_certificate(&self) -> Result<Vec<u8>, Error> {
         self.stream.get_ref().peer_certificate()
     }
@@ -325,7 +321,7 @@ impl SmtpConnection {
     }
 
     /// All the X509 certificates of the chain (DER encoded)
-    #[cfg(any(feature = "rustls-tls", feature = "boring-tls"))]
+    #[cfg(any(feature = "rustls", feature = "boring-tls"))]
     pub fn certificate_chain(&self) -> Result<Vec<Vec<u8>>, Error> {
         self.stream.get_ref().certificate_chain()
     }
diff --git a/src/transport/smtp/client/mod.rs b/src/transport/smtp/client/mod.rs
index df2f742dc..d393157ac 100644
--- a/src/transport/smtp/client/mod.rs
+++ b/src/transport/smtp/client/mod.rs
@@ -33,9 +33,9 @@ pub use self::async_net::AsyncNetworkStream;
 #[cfg(feature = "tokio1")]
 pub use self::async_net::AsyncTokioStream;
 use self::net::NetworkStream;
-#[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+#[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
 pub(super) use self::tls::InnerTlsParameters;
-#[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+#[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
 pub use self::tls::TlsVersion;
 pub use self::{
     connection::SmtpConnection,
diff --git a/src/transport/smtp/client/net.rs b/src/transport/smtp/client/net.rs
index 6be0a992c..dd4e431c5 100644
--- a/src/transport/smtp/client/net.rs
+++ b/src/transport/smtp/client/net.rs
@@ -1,4 +1,4 @@
-#[cfg(feature = "rustls-tls")]
+#[cfg(feature = "rustls")]
 use std::sync::Arc;
 use std::{
     io::{self, Read, Write},
@@ -11,11 +11,11 @@ use std::{
 use boring::ssl::SslStream;
 #[cfg(feature = "native-tls")]
 use native_tls::TlsStream;
-#[cfg(feature = "rustls-tls")]
+#[cfg(feature = "rustls")]
 use rustls::{pki_types::ServerName, ClientConnection, StreamOwned};
 use socket2::{Domain, Protocol, Type};
 
-#[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+#[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
 use super::InnerTlsParameters;
 use super::TlsParameters;
 use crate::transport::smtp::{error, Error};
@@ -36,7 +36,7 @@ enum InnerNetworkStream {
     #[cfg(feature = "native-tls")]
     NativeTls(TlsStream<TcpStream>),
     /// Encrypted TCP stream
-    #[cfg(feature = "rustls-tls")]
+    #[cfg(feature = "rustls")]
     RustlsTls(StreamOwned<ClientConnection, TcpStream>),
     #[cfg(feature = "boring-tls")]
     BoringTls(SslStream<TcpStream>),
@@ -59,7 +59,7 @@ impl NetworkStream {
             InnerNetworkStream::Tcp(s) => s.peer_addr(),
             #[cfg(feature = "native-tls")]
             InnerNetworkStream::NativeTls(s) => s.get_ref().peer_addr(),
-            #[cfg(feature = "rustls-tls")]
+            #[cfg(feature = "rustls")]
             InnerNetworkStream::RustlsTls(s) => s.get_ref().peer_addr(),
             #[cfg(feature = "boring-tls")]
             InnerNetworkStream::BoringTls(s) => s.get_ref().peer_addr(),
@@ -79,7 +79,7 @@ impl NetworkStream {
             InnerNetworkStream::Tcp(s) => s.shutdown(how),
             #[cfg(feature = "native-tls")]
             InnerNetworkStream::NativeTls(s) => s.get_ref().shutdown(how),
-            #[cfg(feature = "rustls-tls")]
+            #[cfg(feature = "rustls")]
             InnerNetworkStream::RustlsTls(s) => s.get_ref().shutdown(how),
             #[cfg(feature = "boring-tls")]
             InnerNetworkStream::BoringTls(s) => s.get_ref().shutdown(how),
@@ -146,17 +146,13 @@ impl NetworkStream {
 
     pub fn upgrade_tls(&mut self, tls_parameters: &TlsParameters) -> Result<(), Error> {
         match &self.inner {
-            #[cfg(not(any(
-                feature = "native-tls",
-                feature = "rustls-tls",
-                feature = "boring-tls"
-            )))]
+            #[cfg(not(any(feature = "native-tls", feature = "rustls", feature = "boring-tls")))]
             InnerNetworkStream::Tcp(_) => {
                 let _ = tls_parameters;
-                panic!("Trying to upgrade an NetworkStream without having enabled either the native-tls or the rustls-tls feature");
+                panic!("Trying to upgrade an NetworkStream without having enabled either the `native-tls` or the `rustls` feature");
             }
 
-            #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+            #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
             InnerNetworkStream::Tcp(_) => {
                 // get owned TcpStream
                 let tcp_stream = mem::replace(&mut self.inner, InnerNetworkStream::None);
@@ -171,7 +167,7 @@ impl NetworkStream {
         }
     }
 
-    #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+    #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
     fn upgrade_tls_impl(
         tcp_stream: TcpStream,
         tls_parameters: &TlsParameters,
@@ -184,7 +180,7 @@ impl NetworkStream {
                     .map_err(error::connection)?;
                 InnerNetworkStream::NativeTls(stream)
             }
-            #[cfg(feature = "rustls-tls")]
+            #[cfg(feature = "rustls")]
             InnerTlsParameters::RustlsTls(connector) => {
                 let domain = ServerName::try_from(tls_parameters.domain())
                     .map_err(|_| error::connection("domain isn't a valid DNS name"))?;
@@ -211,7 +207,7 @@ impl NetworkStream {
             InnerNetworkStream::Tcp(_) => false,
             #[cfg(feature = "native-tls")]
             InnerNetworkStream::NativeTls(_) => true,
-            #[cfg(feature = "rustls-tls")]
+            #[cfg(feature = "rustls")]
             InnerNetworkStream::RustlsTls(_) => true,
             #[cfg(feature = "boring-tls")]
             InnerNetworkStream::BoringTls(_) => true,
@@ -228,7 +224,7 @@ impl NetworkStream {
             InnerNetworkStream::Tcp(_) => Err(error::client("Connection is not encrypted")),
             #[cfg(feature = "native-tls")]
             InnerNetworkStream::NativeTls(_) => panic!("Unsupported"),
-            #[cfg(feature = "rustls-tls")]
+            #[cfg(feature = "rustls")]
             InnerNetworkStream::RustlsTls(_) => panic!("Unsupported"),
             #[cfg(feature = "boring-tls")]
             InnerNetworkStream::BoringTls(stream) => {
@@ -238,13 +234,13 @@ impl NetworkStream {
         }
     }
 
-    #[cfg(any(feature = "rustls-tls", feature = "boring-tls"))]
+    #[cfg(any(feature = "rustls", feature = "boring-tls"))]
     pub fn certificate_chain(&self) -> Result<Vec<Vec<u8>>, Error> {
         match &self.inner {
             InnerNetworkStream::Tcp(_) => Err(error::client("Connection is not encrypted")),
             #[cfg(feature = "native-tls")]
             InnerNetworkStream::NativeTls(_) => panic!("Unsupported"),
-            #[cfg(feature = "rustls-tls")]
+            #[cfg(feature = "rustls")]
             InnerNetworkStream::RustlsTls(stream) => Ok(stream
                 .conn
                 .peer_certificates()
@@ -264,7 +260,7 @@ impl NetworkStream {
         }
     }
 
-    #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+    #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
     pub fn peer_certificate(&self) -> Result<Vec<u8>, Error> {
         match &self.inner {
             InnerNetworkStream::Tcp(_) => Err(error::client("Connection is not encrypted")),
@@ -275,7 +271,7 @@ impl NetworkStream {
                 .unwrap()
                 .to_der()
                 .map_err(error::tls)?),
-            #[cfg(feature = "rustls-tls")]
+            #[cfg(feature = "rustls")]
             InnerNetworkStream::RustlsTls(stream) => Ok(stream
                 .conn
                 .peer_certificates()
@@ -299,7 +295,7 @@ impl NetworkStream {
             InnerNetworkStream::Tcp(stream) => stream.set_read_timeout(duration),
             #[cfg(feature = "native-tls")]
             InnerNetworkStream::NativeTls(stream) => stream.get_ref().set_read_timeout(duration),
-            #[cfg(feature = "rustls-tls")]
+            #[cfg(feature = "rustls")]
             InnerNetworkStream::RustlsTls(stream) => stream.get_ref().set_read_timeout(duration),
             #[cfg(feature = "boring-tls")]
             InnerNetworkStream::BoringTls(stream) => stream.get_ref().set_read_timeout(duration),
@@ -317,7 +313,7 @@ impl NetworkStream {
 
             #[cfg(feature = "native-tls")]
             InnerNetworkStream::NativeTls(stream) => stream.get_ref().set_write_timeout(duration),
-            #[cfg(feature = "rustls-tls")]
+            #[cfg(feature = "rustls")]
             InnerNetworkStream::RustlsTls(stream) => stream.get_ref().set_write_timeout(duration),
             #[cfg(feature = "boring-tls")]
             InnerNetworkStream::BoringTls(stream) => stream.get_ref().set_write_timeout(duration),
@@ -335,7 +331,7 @@ impl Read for NetworkStream {
             InnerNetworkStream::Tcp(s) => s.read(buf),
             #[cfg(feature = "native-tls")]
             InnerNetworkStream::NativeTls(s) => s.read(buf),
-            #[cfg(feature = "rustls-tls")]
+            #[cfg(feature = "rustls")]
             InnerNetworkStream::RustlsTls(s) => s.read(buf),
             #[cfg(feature = "boring-tls")]
             InnerNetworkStream::BoringTls(s) => s.read(buf),
@@ -353,7 +349,7 @@ impl Write for NetworkStream {
             InnerNetworkStream::Tcp(s) => s.write(buf),
             #[cfg(feature = "native-tls")]
             InnerNetworkStream::NativeTls(s) => s.write(buf),
-            #[cfg(feature = "rustls-tls")]
+            #[cfg(feature = "rustls")]
             InnerNetworkStream::RustlsTls(s) => s.write(buf),
             #[cfg(feature = "boring-tls")]
             InnerNetworkStream::BoringTls(s) => s.write(buf),
@@ -369,7 +365,7 @@ impl Write for NetworkStream {
             InnerNetworkStream::Tcp(s) => s.flush(),
             #[cfg(feature = "native-tls")]
             InnerNetworkStream::NativeTls(s) => s.flush(),
-            #[cfg(feature = "rustls-tls")]
+            #[cfg(feature = "rustls")]
             InnerNetworkStream::RustlsTls(s) => s.flush(),
             #[cfg(feature = "boring-tls")]
             InnerNetworkStream::BoringTls(s) => s.flush(),
diff --git a/src/transport/smtp/client/tls.rs b/src/transport/smtp/client/tls.rs
index df407e505..513f4ff5b 100644
--- a/src/transport/smtp/client/tls.rs
+++ b/src/transport/smtp/client/tls.rs
@@ -1,5 +1,5 @@
 use std::fmt::{self, Debug};
-#[cfg(feature = "rustls-tls")]
+#[cfg(feature = "rustls")]
 use std::sync::Arc;
 
 #[cfg(feature = "boring-tls")]
@@ -10,7 +10,7 @@ use boring::{
 };
 #[cfg(feature = "native-tls")]
 use native_tls::{Protocol, TlsConnector};
-#[cfg(feature = "rustls-tls")]
+#[cfg(feature = "rustls")]
 use rustls::{
     client::danger::{HandshakeSignatureValid, ServerCertVerified, ServerCertVerifier},
     crypto::{verify_tls12_signature, verify_tls13_signature, CryptoProvider},
@@ -19,13 +19,13 @@ use rustls::{
     ClientConfig, DigitallySignedStruct, Error as TlsError, RootCertStore, SignatureScheme,
 };
 
-#[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+#[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
 use crate::transport::smtp::{error, Error};
 
 /// TLS protocol versions.
 #[derive(Debug, Copy, Clone)]
 #[non_exhaustive]
-#[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+#[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
 pub enum TlsVersion {
     /// TLS 1.0
     ///
@@ -85,10 +85,10 @@ pub enum Tls {
     ///
     /// Warning: A malicious intermediary could intercept the `STARTTLS` flag,
     /// causing lettre to believe the server only supports plaintext connections.
-    #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+    #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
     #[cfg_attr(
         docsrs,
-        doc(cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls")))
+        doc(cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls")))
     )]
     Opportunistic(TlsParameters),
     /// Begin with a plaintext connection and require `STARTTLS` for security.
@@ -100,10 +100,10 @@ pub enum Tls {
     /// Unlike [`Tls::Opportunistic`], this option is secure against MITM attacks.
     /// For optimal security and performance, consider using [`Tls::Wrapper`] instead,
     /// as it requires fewer roundtrips to establish a secure connection.
-    #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+    #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
     #[cfg_attr(
         docsrs,
-        doc(cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls")))
+        doc(cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls")))
     )]
     Required(TlsParameters),
     /// Establish a connection wrapped in TLS from the start.
@@ -113,10 +113,10 @@ pub enum Tls {
     /// transmitting any sensitive data.
     ///
     /// This is the fastest and most secure option for establishing a connection.
-    #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+    #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
     #[cfg_attr(
         docsrs,
-        doc(cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls")))
+        doc(cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls")))
     )]
     Wrapper(TlsParameters),
 }
@@ -125,11 +125,11 @@ impl Debug for Tls {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match &self {
             Self::None => f.pad("None"),
-            #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+            #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
             Self::Opportunistic(_) => f.pad("Opportunistic"),
-            #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+            #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
             Self::Required(_) => f.pad("Required"),
-            #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+            #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
             Self::Wrapper(_) => f.pad("Wrapper"),
         }
     }
@@ -153,7 +153,7 @@ pub enum CertificateStore {
     /// Use a hardcoded set of Mozilla roots via the `webpki-roots` crate.
     ///
     /// This option is only available in the rustls backend.
-    #[cfg(feature = "rustls-tls")]
+    #[cfg(all(feature = "rustls", feature = "webpki-roots"))]
     WebpkiRoots,
     /// Don't use any system certificates.
     None,
@@ -178,7 +178,7 @@ pub struct TlsParametersBuilder {
     identity: Option<Identity>,
     accept_invalid_hostnames: bool,
     accept_invalid_certs: bool,
-    #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+    #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
     min_tls_version: TlsVersion,
 }
 
@@ -192,7 +192,7 @@ impl TlsParametersBuilder {
             identity: None,
             accept_invalid_hostnames: false,
             accept_invalid_certs: false,
-            #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+            #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
             min_tls_version: TlsVersion::Tlsv12,
         }
     }
@@ -230,10 +230,10 @@ impl TlsParametersBuilder {
     /// including those from other sites, are trusted.
     ///
     /// This method introduces significant vulnerabilities to man-in-the-middle attacks.
-    #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+    #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
     #[cfg_attr(
         docsrs,
-        doc(cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls")))
+        doc(cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls")))
     )]
     pub fn dangerous_accept_invalid_hostnames(mut self, accept_invalid_hostnames: bool) -> Self {
         self.accept_invalid_hostnames = accept_invalid_hostnames;
@@ -243,7 +243,7 @@ impl TlsParametersBuilder {
     /// Controls which minimum TLS version is allowed
     ///
     /// Defaults to [`Tlsv12`][TlsVersion::Tlsv12].
-    #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+    #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
     pub fn set_min_tls_version(mut self, min_tls_version: TlsVersion) -> Self {
         self.min_tls_version = min_tls_version;
         self
@@ -272,17 +272,17 @@ impl TlsParametersBuilder {
 
     /// Creates a new `TlsParameters` using native-tls, boring-tls or rustls
     /// depending on which one is available
-    #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+    #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
     #[cfg_attr(
         docsrs,
-        doc(cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls")))
+        doc(cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls")))
     )]
     pub fn build(self) -> Result<TlsParameters, Error> {
-        #[cfg(feature = "rustls-tls")]
+        #[cfg(feature = "rustls")]
         return self.build_rustls();
-        #[cfg(all(not(feature = "rustls-tls"), feature = "native-tls"))]
+        #[cfg(all(not(feature = "rustls"), feature = "native-tls"))]
         return self.build_native();
-        #[cfg(all(not(feature = "rustls-tls"), feature = "boring-tls"))]
+        #[cfg(all(not(feature = "rustls"), feature = "boring-tls"))]
         return self.build_boring();
     }
 
@@ -396,8 +396,8 @@ impl TlsParametersBuilder {
     }
 
     /// Creates a new `TlsParameters` using rustls with the provided configuration
-    #[cfg(feature = "rustls-tls")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "rustls-tls")))]
+    #[cfg(feature = "rustls")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "rustls")))]
     pub fn build_rustls(self) -> Result<TlsParameters, Error> {
         let just_version3 = &[&rustls::version::TLS13];
         let supported_versions = match self.min_tls_version {
@@ -411,9 +411,7 @@ impl TlsParametersBuilder {
             TlsVersion::Tlsv13 => just_version3,
         };
 
-        let crypto_provider = CryptoProvider::get_default()
-            .cloned()
-            .unwrap_or_else(|| Arc::new(rustls::crypto::ring::default_provider()));
+        let crypto_provider = crate::rustls_crypto::crypto_provider();
         let tls = ClientConfig::builder_with_provider(Arc::clone(&crypto_provider))
             .with_protocol_versions(supported_versions)
             .map_err(error::tls)?;
@@ -436,7 +434,7 @@ impl TlsParametersBuilder {
             let _ = (errors_len, added, ignored);
         }
 
-        #[cfg(feature = "rustls-tls")]
+        #[cfg(all(feature = "rustls", feature = "webpki-roots"))]
         fn load_webpki_roots(store: &mut RootCertStore) {
             store.extend(webpki_roots::TLS_SERVER_ROOTS.iter().cloned());
         }
@@ -445,10 +443,10 @@ impl TlsParametersBuilder {
             CertificateStore::Default => {
                 #[cfg(feature = "rustls-native-certs")]
                 load_native_roots(&mut root_cert_store);
-                #[cfg(not(feature = "rustls-native-certs"))]
+                #[cfg(all(not(feature = "rustls-native-certs"), feature = "webpki-roots"))]
                 load_webpki_roots(&mut root_cert_store);
             }
-            #[cfg(feature = "rustls-tls")]
+            #[cfg(all(feature = "rustls", feature = "webpki-roots"))]
             CertificateStore::WebpkiRoots => {
                 load_webpki_roots(&mut root_cert_store);
             }
@@ -495,7 +493,7 @@ impl TlsParametersBuilder {
 pub enum InnerTlsParameters {
     #[cfg(feature = "native-tls")]
     NativeTls(TlsConnector),
-    #[cfg(feature = "rustls-tls")]
+    #[cfg(feature = "rustls")]
     RustlsTls(Arc<ClientConfig>),
     #[cfg(feature = "boring-tls")]
     BoringTls(SslConnector),
@@ -504,10 +502,10 @@ pub enum InnerTlsParameters {
 impl TlsParameters {
     /// Creates a new `TlsParameters` using native-tls or rustls
     /// depending on which one is available
-    #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+    #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
     #[cfg_attr(
         docsrs,
-        doc(cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls")))
+        doc(cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls")))
     )]
     pub fn new(domain: String) -> Result<Self, Error> {
         TlsParametersBuilder::new(domain).build()
@@ -526,8 +524,8 @@ impl TlsParameters {
     }
 
     /// Creates a new `TlsParameters` using rustls
-    #[cfg(feature = "rustls-tls")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "rustls-tls")))]
+    #[cfg(feature = "rustls")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "rustls")))]
     pub fn new_rustls(domain: String) -> Result<Self, Error> {
         TlsParametersBuilder::new(domain).build_rustls()
     }
@@ -550,13 +548,13 @@ impl TlsParameters {
 pub struct Certificate {
     #[cfg(feature = "native-tls")]
     native_tls: native_tls::Certificate,
-    #[cfg(feature = "rustls-tls")]
+    #[cfg(feature = "rustls")]
     rustls: Vec<CertificateDer<'static>>,
     #[cfg(feature = "boring-tls")]
     boring_tls: boring::x509::X509,
 }
 
-#[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+#[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
 impl Certificate {
     /// Create a `Certificate` from a DER encoded certificate
     pub fn from_der(der: Vec<u8>) -> Result<Self, Error> {
@@ -569,7 +567,7 @@ impl Certificate {
         Ok(Self {
             #[cfg(feature = "native-tls")]
             native_tls: native_tls_cert,
-            #[cfg(feature = "rustls-tls")]
+            #[cfg(feature = "rustls")]
             rustls: vec![der.into()],
             #[cfg(feature = "boring-tls")]
             boring_tls: boring_tls_cert,
@@ -584,7 +582,7 @@ impl Certificate {
         #[cfg(feature = "boring-tls")]
         let boring_tls_cert = boring::x509::X509::from_pem(pem).map_err(error::tls)?;
 
-        #[cfg(feature = "rustls-tls")]
+        #[cfg(feature = "rustls")]
         let rustls_cert = {
             CertificateDer::pem_slice_iter(pem)
                 .collect::<Result<Vec<_>, pki_types::pem::Error>>()
@@ -594,7 +592,7 @@ impl Certificate {
         Ok(Self {
             #[cfg(feature = "native-tls")]
             native_tls: native_tls_cert,
-            #[cfg(feature = "rustls-tls")]
+            #[cfg(feature = "rustls")]
             rustls: rustls_cert,
             #[cfg(feature = "boring-tls")]
             boring_tls: boring_tls_cert,
@@ -613,7 +611,7 @@ impl Debug for Certificate {
 pub struct Identity {
     #[cfg(feature = "native-tls")]
     native_tls: native_tls::Identity,
-    #[cfg(feature = "rustls-tls")]
+    #[cfg(feature = "rustls")]
     rustls_tls: (Vec<CertificateDer<'static>>, PrivateKeyDer<'static>),
     #[cfg(feature = "boring-tls")]
     boring_tls: (boring::x509::X509, PKey<boring::pkey::Private>),
@@ -630,7 +628,7 @@ impl Clone for Identity {
         Identity {
             #[cfg(feature = "native-tls")]
             native_tls: self.native_tls.clone(),
-            #[cfg(feature = "rustls-tls")]
+            #[cfg(feature = "rustls")]
             rustls_tls: (self.rustls_tls.0.clone(), self.rustls_tls.1.clone_key()),
             #[cfg(feature = "boring-tls")]
             boring_tls: (self.boring_tls.0.clone(), self.boring_tls.1.clone()),
@@ -638,13 +636,13 @@ impl Clone for Identity {
     }
 }
 
-#[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+#[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
 impl Identity {
     pub fn from_pem(pem: &[u8], key: &[u8]) -> Result<Self, Error> {
         Ok(Self {
             #[cfg(feature = "native-tls")]
             native_tls: Identity::from_pem_native_tls(pem, key)?,
-            #[cfg(feature = "rustls-tls")]
+            #[cfg(feature = "rustls")]
             rustls_tls: Identity::from_pem_rustls_tls(pem, key)?,
             #[cfg(feature = "boring-tls")]
             boring_tls: Identity::from_pem_boring_tls(pem, key)?,
@@ -656,7 +654,7 @@ impl Identity {
         native_tls::Identity::from_pkcs8(pem, key).map_err(error::tls)
     }
 
-    #[cfg(feature = "rustls-tls")]
+    #[cfg(feature = "rustls")]
     fn from_pem_rustls_tls(
         pem: &[u8],
         key: &[u8],
@@ -683,7 +681,7 @@ impl Identity {
     }
 }
 
-#[cfg(feature = "rustls-tls")]
+#[cfg(feature = "rustls")]
 #[derive(Debug)]
 struct InvalidCertsVerifier {
     ignore_invalid_hostnames: bool,
@@ -692,7 +690,7 @@ struct InvalidCertsVerifier {
     crypto_provider: Arc<CryptoProvider>,
 }
 
-#[cfg(feature = "rustls-tls")]
+#[cfg(feature = "rustls")]
 impl ServerCertVerifier for InvalidCertsVerifier {
     fn verify_server_cert(
         &self,
diff --git a/src/transport/smtp/connection_url.rs b/src/transport/smtp/connection_url.rs
index 8084b0553..eb2b121a3 100644
--- a/src/transport/smtp/connection_url.rs
+++ b/src/transport/smtp/connection_url.rs
@@ -2,7 +2,7 @@ use std::borrow::Cow;
 
 use url::Url;
 
-#[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+#[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
 use super::client::{Tls, TlsParameters};
 #[cfg(any(feature = "tokio1", feature = "async-std1"))]
 use super::AsyncSmtpTransportBuilder;
@@ -82,19 +82,19 @@ pub(crate) fn from_connection_url<B: TransportBuilder>(connection_url: &str) ->
         ("smtp", None) => {
             builder = builder.port(connection_url.port().unwrap_or(SMTP_PORT));
         }
-        #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+        #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
         ("smtp", Some("required")) => {
             builder = builder
                 .port(connection_url.port().unwrap_or(SUBMISSION_PORT))
                 .tls(Tls::Required(TlsParameters::new(host.into())?));
         }
-        #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+        #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
         ("smtp", Some("opportunistic")) => {
             builder = builder
                 .port(connection_url.port().unwrap_or(SUBMISSION_PORT))
                 .tls(Tls::Opportunistic(TlsParameters::new(host.into())?));
         }
-        #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+        #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
         ("smtps", _) => {
             builder = builder
                 .port(connection_url.port().unwrap_or(SUBMISSIONS_PORT))
diff --git a/src/transport/smtp/error.rs b/src/transport/smtp/error.rs
index ca59cdcd7..4131fb0f9 100644
--- a/src/transport/smtp/error.rs
+++ b/src/transport/smtp/error.rs
@@ -68,10 +68,10 @@ impl Error {
     }
 
     /// Returns true if the error is from TLS
-    #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+    #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
     #[cfg_attr(
         docsrs,
-        doc(cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls")))
+        doc(cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls")))
     )]
     pub fn is_tls(&self) -> bool {
         matches!(self.inner.kind, Kind::Tls)
@@ -107,9 +107,9 @@ pub(crate) enum Kind {
     /// TLS error
     #[cfg_attr(
         docsrs,
-        doc(cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls")))
+        doc(cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls")))
     )]
-    #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+    #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
     Tls,
 }
 
@@ -134,7 +134,7 @@ impl fmt::Display for Error {
             Kind::Client => f.write_str("internal client error")?,
             Kind::Network => f.write_str("network error")?,
             Kind::Connection => f.write_str("Connection error")?,
-            #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+            #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
             Kind::Tls => f.write_str("tls error")?,
             Kind::Transient(code) => {
                 write!(f, "transient error ({code})")?;
@@ -185,7 +185,7 @@ pub(crate) fn connection<E: Into<BoxError>>(e: E) -> Error {
     Error::new(Kind::Connection, Some(e))
 }
 
-#[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+#[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
 pub(crate) fn tls<E: Into<BoxError>>(e: E) -> Error {
     Error::new(Kind::Tls, Some(e))
 }
diff --git a/src/transport/smtp/mod.rs b/src/transport/smtp/mod.rs
index 563fc5bd6..20373145c 100644
--- a/src/transport/smtp/mod.rs
+++ b/src/transport/smtp/mod.rs
@@ -32,7 +32,7 @@
 //! do the following:
 //!
 //! ```rust,no_run
-//! # #[cfg(all(feature = "builder", any(feature = "native-tls", feature = "rustls-tls")))]
+//! # #[cfg(all(feature = "builder", any(feature = "native-tls", feature = "rustls")))]
 //! # fn test() -> Result<(), Box<dyn std::error::Error>> {
 //! use lettre::{
 //!     message::header::ContentType,
@@ -73,7 +73,7 @@
 //! For more information take a look at [`SmtpTransport::from_url`] or [`AsyncSmtpTransport::from_url`].
 //!
 //! ```rust,no_run
-//! # #[cfg(all(feature = "builder", any(feature = "native-tls", feature = "rustls-tls")))]
+//! # #[cfg(all(feature = "builder", any(feature = "native-tls", feature = "rustls")))]
 //! # fn test() -> Result<(), Box<dyn std::error::Error>> {
 //! use lettre::{
 //!     message::header::ContentType,
@@ -101,7 +101,7 @@
 //! #### Advanced configuration with custom TLS settings
 //!
 //! ```rust,no_run
-//! # #[cfg(all(feature = "builder", any(feature = "native-tls", feature = "rustls-tls")))]
+//! # #[cfg(all(feature = "builder", any(feature = "native-tls", feature = "rustls")))]
 //! # fn test() -> Result<(), Box<dyn std::error::Error>> {
 //! use std::fs;
 //!
@@ -146,7 +146,7 @@
 //! In a webserver context it may go about this:
 //!
 //! ```rust,no_run
-//! # #[cfg(all(feature = "builder", any(feature = "native-tls", feature = "rustls-tls")))]
+//! # #[cfg(all(feature = "builder", any(feature = "native-tls", feature = "rustls")))]
 //! # fn test() {
 //! use lettre::{
 //!     message::header::ContentType,
@@ -199,7 +199,7 @@ pub use self::{
     error::Error,
     transport::{SmtpTransport, SmtpTransportBuilder},
 };
-#[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+#[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
 use crate::transport::smtp::client::TlsParameters;
 use crate::transport::smtp::{
     authentication::{Credentials, Mechanism, DEFAULT_MECHANISMS},
diff --git a/src/transport/smtp/transport.rs b/src/transport/smtp/transport.rs
index edf039abb..a6c92bf27 100644
--- a/src/transport/smtp/transport.rs
+++ b/src/transport/smtp/transport.rs
@@ -7,7 +7,7 @@ use super::pool::sync_impl::Pool;
 #[cfg(feature = "pool")]
 use super::PoolConfig;
 use super::{ClientId, Credentials, Error, Mechanism, Response, SmtpConnection, SmtpInfo};
-#[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+#[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
 use super::{Tls, TlsParameters, SUBMISSIONS_PORT, SUBMISSION_PORT};
 use crate::{address::Envelope, Transport};
 
@@ -77,10 +77,10 @@ impl SmtpTransport {
     ///
     /// Creates an encrypted transport over submissions port, using the provided domain
     /// to validate TLS certificates.
-    #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+    #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
     #[cfg_attr(
         docsrs,
-        doc(cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls")))
+        doc(cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls")))
     )]
     pub fn relay(relay: &str) -> Result<SmtpTransportBuilder, Error> {
         let tls_parameters = TlsParameters::new(relay.into())?;
@@ -101,10 +101,10 @@ impl SmtpTransport {
     ///
     /// An error is returned if the connection can't be upgraded. No credentials
     /// or emails will be sent to the server, protecting from downgrade attacks.
-    #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+    #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
     #[cfg_attr(
         docsrs,
-        doc(cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls")))
+        doc(cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls")))
     )]
     pub fn starttls_relay(relay: &str) -> Result<SmtpTransportBuilder, Error> {
         let tls_parameters = TlsParameters::new(relay.into())?;
@@ -230,10 +230,10 @@ impl SmtpTransport {
     /// # Ok(())
     /// # }
     /// ```
-    #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+    #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
     #[cfg_attr(
         docsrs,
-        doc(cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls")))
+        doc(cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls")))
     )]
     pub fn from_url(connection_url: &str) -> Result<SmtpTransportBuilder, Error> {
         super::connection_url::from_connection_url(connection_url)
@@ -333,10 +333,10 @@ impl SmtpTransportBuilder {
     ///
     /// Using the wrong [`Tls`] and [`Self::port`] combination may
     /// lead to hard to debug IO errors coming from the TLS library.
-    #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+    #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
     #[cfg_attr(
         docsrs,
-        doc(cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls")))
+        doc(cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls")))
     )]
     pub fn tls(mut self, tls: Tls) -> Self {
         self.info.tls = tls;
@@ -380,7 +380,7 @@ impl SmtpClient {
     pub fn connection(&self) -> Result<SmtpConnection, Error> {
         #[allow(clippy::match_single_binding)]
         let tls_parameters = match &self.info.tls {
-            #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+            #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
             Tls::Wrapper(tls_parameters) => Some(tls_parameters),
             _ => None,
         };
@@ -394,7 +394,7 @@ impl SmtpClient {
             None,
         )?;
 
-        #[cfg(any(feature = "native-tls", feature = "rustls-tls", feature = "boring-tls"))]
+        #[cfg(any(feature = "native-tls", feature = "rustls", feature = "boring-tls"))]
         match &self.info.tls {
             Tls::Opportunistic(tls_parameters) => {
                 if conn.can_starttls() {


Test patch:
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 096e4b346..c8ca0a2ad 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -57,12 +57,12 @@ jobs:
 
       - name: Setup cache
         uses: Swatinem/rust-cache@v2
-      
+
       - name: Install cargo hack
         run: cargo install cargo-hack --debug
 
       - name: Check with cargo hack
-        run: cargo hack check --feature-powerset --depth 3
+        run: cargo hack check --feature-powerset --depth 3 --at-least-one-of aws-lc-rs,ring --at-least-one-of rustls-native-certs,webpki-roots
 
   test:
     name: test / ${{ matrix.name }}
@@ -90,7 +90,7 @@ jobs:
       - name: Setup cache
         uses: Swatinem/rust-cache@v2
 
-      - name: Install postfix  
+      - name: Install postfix
         run: |
           DEBIAN_FRONTEND=noninteractive sudo apt-get update
           DEBIAN_FRONTEND=noninteractive sudo apt-get -y install postfix
@@ -119,10 +119,10 @@ jobs:
         run: cargo test
 
       - name: Test with all features (-native-tls)
-        run: cargo test --no-default-features --features async-std1,async-std1-rustls-tls,boring-tls,builder,dkim,file-transport,file-transport-envelope,hostname,mime03,pool,rustls-native-certs,rustls-tls,sendmail-transport,smtp-transport,tokio1,tokio1-boring-tls,tokio1-rustls-tls,tracing
-  
+        run: cargo test --no-default-features --features async-std1,async-std1-rustls,aws-lc-rs,rustls-native-certs,boring-tls,builder,dkim,file-transport,file-transport-envelope,hostname,mime03,pool,rustls-native-certs,rustls,sendmail-transport,smtp-transport,tokio1,tokio1-boring-tls,tokio1-rustls,tracing
+
       - name: Test with all features (-boring-tls)
-        run: cargo test --no-default-features --features async-std1,async-std1-rustls-tls,builder,dkim,file-transport,file-transport-envelope,hostname,mime03,native-tls,pool,rustls-native-certs,rustls-tls,sendmail-transport,smtp-transport,tokio1,tokio1-native-tls,tokio1-rustls-tls,tracing
+        run: cargo test --no-default-features --features async-std1,async-std1-rustls,aws-lc-rs,rustls-native-certs,builder,dkim,file-transport,file-transport-envelope,hostname,mime03,native-tls,pool,rustls-native-certs,rustls,sendmail-transport,smtp-transport,tokio1,tokio1-native-tls,tokio1-rustls,tracing
 
 #  coverage:
 #    name: Coverage