Add test to ensure the same signature is used in both cases.

Author: paragonie-security

src/Crypto/Signature/SchnorrSigner.php

@@ -65,18 +65,26 @@ public function verifyWithKey(
     ): bool {
         $ptX = gmp_strval($key->getPoint()->getX(), 16);
         $x = str_pad($ptX, 64, '0', STR_PAD_LEFT);
+        $serialized = $this->formatSignature($key, $signature);
+        return $this->verify($x, $serialized, $message);
+    }
 
+    /**
+     * Format a Signature object as expected by verify()
+     *
+     * @param PublicKeyInterface $publicKey
+     * @param SignatureInterface $signature
+     * @return string
+     */
+    public function formatSignature(PublicKeyInterface $publicKey, SignatureInterface $signature): string
+    {
         // Bit-size >> 2 == number of hex characters
-        $l = $key->getCurve()->getSize() >> 2;
+        $l = $publicKey->getCurve()->getSize() >> 2;
 
         // Encode as R || S, as hex strings:
         $r = str_pad(gmp_strval($signature->getR(), 16), $l, '0', STR_PAD_LEFT);
         $s = str_pad(gmp_strval($signature->getS(), 16), $l, '0', STR_PAD_LEFT);
-        $serialized = $r . $s;
-
-        // var_dump($l, $serialized, $r, $s); exit;
-
-        return $this->verify($x, $serialized, $message);
+        return $r . $s;
     }
 
     /**

tests/unit/Crypto/Signature/SchnorrSignatureTest.php

@@ -86,18 +86,19 @@ public function testSchnorrVerificationAndSigning(
 
         // -- // New in v2.5.0 // -- //
 
+        $signer = (new SchnorrSigner());
         // Create objects for the same key pair:
         $generator = SecureCurveFactory::getGeneratorByName('secp256k1');
         $skObject = new PrivateKey(new ConstantTimeMath(), $generator, gmp_init($privateKey, 16));
         $pkObject = $skObject->getPublicKey();
 
         // Ensure the same Schnorr signature is created:
-        $signResult2 = (new SchnorrSigner())->signWithKey($skObject, $message, $auxRand);
-        $verifyResult2 = (new SchnorrSigner())->verifyWithKey($pkObject, $signResult2, $message);
+        $signResult2 = $signer->signWithKey($skObject, $message, $auxRand);
+        $verifyResult2 = $signer->verifyWithKey($pkObject, $signResult2, $message);
         self::assertSame($expectedResult, $verifyResult2);
 
-        // self::assertSame(strtolower($signature), $signResult2['signature']);
         // Ensure the same verification result occurs:
+        self::assertSame($signer->formatSignature($pkObject, $signResult2), $signResult['signature']);
     }
 
     /**