Fix "non-canonical s" check with [email protected] (#5978)

Signed-off-by: Nikita Khateev <[email protected]>
Co-authored-by: Hadrien Croubois <[email protected]>

Author: KitHat

test/utils/cryptography/ECDSA.test.js

@@ -1,6 +1,7 @@
 const { ethers } = require('hardhat');
 const { expect } = require('chai');
 const { loadFixture } = require('@nomicfoundation/hardhat-network-helpers');
+const { secp256k1 } = require('@noble/curves/secp256k1');
 
 const TEST_MESSAGE = ethers.id('OpenZeppelin');
 const WRONG_MESSAGE = ethers.id('Nope');
@@ -242,6 +243,10 @@ describe('ECDSA', function () {
       const s = ethers.dataSlice(highSSignature, 32, 64);
       const v = ethers.dataSlice(highSSignature, 64, 65);
 
+      // In ethers v6.15.0+, the library no longer throws 'non-canonical s' error for high-s signatures. This
+      // assertion verifies we are in fact dealing with a high-s value that the ECDSA library should reject.
+      expect(ethers.toBigInt(s)).to.be.gt(secp256k1.CURVE.n / 2n);
+
       await expect(this.mock.$recover(message, highSSignature))
         .to.be.revertedWithCustomError(this.mock, 'ECDSAInvalidSignatureS')
         .withArgs(s);
@@ -251,7 +256,6 @@ describe('ECDSA', function () {
       await expect(this.mock.getFunction('$recover(bytes32,uint8,bytes32,bytes32)')(TEST_MESSAGE, v, r, s))
         .to.be.revertedWithCustomError(this.mock, 'ECDSAInvalidSignatureS')
         .withArgs(s);
-      expect(() => ethers.Signature.from(highSSignature)).to.throw('non-canonical s');
     });
   });