taler-typescript-core

commit 31e32a271d9a2c7d1b0998dc01f5a74d2da7911a
parent 13b42e40652d78f4797c1e393ca03fa906dfc9f3
Author: Florian Dold <dold@taler.net>
Date:   Mon, 20 Jul 2026 13:58:58 +0200

util: fix age restriction commit comparison, test

Diffstat:
M
packages/taler-util/src/taler-crypto.test.ts
 | 
26
++++++++++++++++++++++++++
M
packages/taler-util/src/taler-crypto.ts
 | 
2
+-

2 files changed, 27 insertions(+), 1 deletion(-)
diff --git a/packages/taler-util/src/taler-crypto.test.ts b/packages/taler-util/src/taler-crypto.test.ts
@@ -53,6 +53,7 @@ import {
   hpkeSealOneshotNorand,
   hpkeComputeNonce,
   hpkeOpenOneshot,
+  AgeRestriction,
 } from "./taler-crypto.js";
 import { sha512 } from "./kdf.js";
 import * as nacl from "./nacl-fast.js";
@@ -408,6 +409,31 @@ test("taler age restriction crypto", async (t) => {
   assert.deepStrictEqual(pub2, pub2Ref);
 });
 
+test("age restriction commitCompare accepts a matching derived commitment", async (t) => {
+  const mask = 0x7f; // arbitrary bitmask with bit 0 set, as required by restrictionCommit
+  const proof = await AgeRestriction.restrictionCommit(mask, 0);
+  const salt = getRandomBytes(32);
+  const derived = await AgeRestriction.commitmentDerive(proof, salt);
+
+  // By definition (see doc comment on commitCompare): derived.commitment
+  // should equal proof.commitment * salt.
+  const ok = await AgeRestriction.commitCompare(
+    derived.commitment,
+    proof.commitment,
+    salt,
+  );
+  assert.strictEqual(ok, true);
+
+  // A commitment derived with a different salt must not match.
+  const otherSalt = getRandomBytes(32);
+  const notOk = await AgeRestriction.commitCompare(
+    derived.commitment,
+    proof.commitment,
+    otherSalt,
+  );
+  assert.strictEqual(notOk, false);
+});
+
 test("edx signing", async (t) => {
   const priv1 = await Edx25519.keyCreate();
   const pub1 = await Edx25519.getPublic(priv1);
diff --git a/packages/taler-util/src/taler-crypto.ts b/packages/taler-util/src/taler-crypto.ts
@@ -1445,7 +1445,7 @@ export namespace AgeRestriction {
         decodeCrock(c2.publicKeys[i]),
         salt,
       );
-      if (k1 != k2) {
+      if (!nacl.verify(k1, k2)) {
         return false;
       }
     }