exact canonicalization via registry shared module (approximate emit kept as labeled fallback); anchor hash-mismatch guard; examples use bare 64-hex dataset.hash

index.html

@@ -225,7 +225,7 @@ comparator: ">="
 threshold: 0.92
 dataset:
   id: imagenet-val-2012
-  hash: sha256:e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
+  hash: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
 seed: 42
 producer:
   id: falsify.dev
@@ -276,7 +276,7 @@ comparator: ">="
 threshold: 0.92
 dataset:
   id: imagenet-val-2012
-  hash: sha256:e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
+  hash: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
 seed: 42
 producer:
   id: falsify.dev
@@ -303,8 +303,21 @@ function sortObject(o) {
   return o;
 }
 
-// Approximate js-yaml canonical dump matching PyYAML safe_dump(default_flow_style=false, sort_keys=true, allow_unicode=true)
+// Exact canonicalization: import the registry's own canonical.js (the same
+// module its server commits with, vector-gated in CI). Falls back to the older
+// approximate js-yaml emit if the module fails to load; the status pill says which.
+let sharedCanon = null;
+import('https://registry.falsify.dev/vendor/canonical.js')
+  .then(m => { sharedCanon = m; update(); })
+  .catch(() => { /* approximate fallback stays active */ });
+
 function canonicalise(obj) {
+  if (sharedCanon) return sharedCanon.canonicalize(obj);
+  return canonicaliseApprox(obj);
+}
+
+// Approximate js-yaml canonical dump matching PyYAML safe_dump(default_flow_style=false, sort_keys=true, allow_unicode=true)
+function canonicaliseApprox(obj) {
   if (typeof jsyaml === 'undefined') throw new Error('YAML lib not loaded');
   let s = jsyaml.dump(sortObject(obj), {
     indent: 2,
@@ -363,6 +376,7 @@ async function update() {
 
   const h = await sha256(canon);
   hashEl.textContent = 'sha256:' + h;
+  try { srcMsg.textContent = sharedCanon ? 'canonical (exact, registry module)' : 'canonical (approximate fallback)'; } catch (_) {}
   srcMsg.className = 'ok';
   srcMsg.textContent = 'canonical';
 }
@@ -423,6 +437,15 @@ $('anchor').addEventListener('click', async () => {
       throw new Error('registry returned ' + res.status);
     }
     const data = await res.json();
+    const localHash = (hashEl.textContent || '').replace(/^sha256:/, '');
+    const remoteHash = (data.hash || '').replace(/^sha256:/, '');
+    if (localHash && remoteHash && localHash !== remoteHash) {
+      btn.textContent = 'HASH MISMATCH — registry disagrees with this page';
+      btn.disabled = false;
+      alert('Hash mismatch.\n\nThis page computed  ' + localHash + '\nthe registry returned ' + remoteHash
+        + '\n\nDo not use this receipt. Re-verify with the Python CLI (falsify lock) and report this at github.com/studio-11-co/falsify-registry.');
+      return;
+    }
     showResults(data);
   } catch (e) {
     btn.textContent = 'anchor failed: ' + e.message;