Move computeMLDSAMu helper to TestUtil

CMakeLists.txt

@@ -274,14 +274,14 @@ set(C_SRC
     csrc/libcrypto_rng.cpp
     csrc/loader.cpp
     csrc/md5.cpp
-    csrc/public_utils.cpp
     csrc/rsa_cipher.cpp
     csrc/rsa_gen.cpp
     csrc/sha1.cpp
     csrc/sha256.cpp
     csrc/sha384.cpp
     csrc/sha512.cpp
     csrc/sign.cpp
+    csrc/test_util.cpp
     csrc/testhooks.cpp
     csrc/util.cpp
     csrc/util_class.cpp

csrc/public_utils.cpp → csrc/test_util.cpp

@@ -10,11 +10,11 @@
 namespace AmazonCorrettoCryptoProvider {
 
 /*
- * Class:     com_amazon_corretto_crypto_provider_Utils
+ * Class:     com_amazon_corretto_crypto_provider_test_TestUtil
  * Method:    computeMLDSAMuInternal
  * Signature: ([B[B)[B
  */
-extern "C" JNIEXPORT jbyteArray JNICALL Java_com_amazon_corretto_crypto_provider_PublicUtils_computeMLDSAMuInternal(
+extern "C" JNIEXPORT jbyteArray JNICALL Java_com_amazon_corretto_crypto_provider_test_TestUtil_computeMLDSAMuInternal(
     JNIEnv* pEnv, jclass, jbyteArray pubKeyEncodedArr, jbyteArray messageArr)
 {
     try {

tst/com/amazon/corretto/crypto/provider/test/MLDSATest.java

@@ -11,7 +11,6 @@
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import com.amazon.corretto.crypto.provider.AmazonCorrettoCryptoProvider;
-import com.amazon.corretto.crypto.provider.PublicUtils;
 import java.security.InvalidKeyException;
 import java.security.KeyFactory;
 import java.security.KeyPair;
@@ -271,7 +270,7 @@ public void testExtMu(TestParams params) throws Exception {
     PublicKey pub = params.pub;
 
     byte[] message = Arrays.copyOf(params.message, params.message.length);
-    byte[] mu = PublicUtils.computeMLDSAMu(pub, message);
+    byte[] mu = TestUtil.computeMLDSAMu(pub, message);
     assertEquals(64, mu.length);
     byte[] fakeMu = new byte[64];
     Arrays.fill(fakeMu, (byte) 0);
@@ -317,4 +316,22 @@ public void testExtMu(TestParams params) throws Exception {
     extMuVerifier.update(mu);
     assertFalse(extMuVerifier.verify(signatureBytes));
   }
+
+  @ParameterizedTest
+  @ValueSource(strings = {"ML-DSA-44", "ML-DSA-65", "ML-DSA-87"})
+  public void testComputeMLDSAExtMu(String algorithm) throws Exception {
+    KeyPair keyPair = KeyPairGenerator.getInstance(algorithm, NATIVE_PROVIDER).generateKeyPair();
+    PublicKey nativePub = keyPair.getPublic();
+    KeyFactory bcKf = KeyFactory.getInstance("ML-DSA", TestUtil.BC_PROVIDER);
+    PublicKey bcPub = bcKf.generatePublic(new X509EncodedKeySpec(nativePub.getEncoded()));
+
+    byte[] message = new byte[256];
+    Arrays.fill(message, (byte) 0x41);
+    byte[] mu = TestUtil.computeMLDSAMu(nativePub, message);
+    assertEquals(64, mu.length);
+    // We don't have any other implementations of mu calculation to test against, so just assert
+    // that mu is equivalent
+    // generated from both ACCP and BouncyCastle keys.
+    assertArrayEquals(mu, TestUtil.computeMLDSAMu(bcPub, message));
+  }
 }

tst/com/amazon/corretto/crypto/provider/test/TestUtil.java

@@ -17,6 +17,7 @@
 import java.nio.ByteBuffer;
 import java.security.NoSuchAlgorithmException;
 import java.security.Provider;
+import java.security.PublicKey;
 import java.security.SecureRandom;
 import java.security.Security;
 import java.util.ArrayList;
@@ -841,4 +842,22 @@ static boolean edKeyFactoryRegistered() {
     return "true"
         .equals(System.getProperty("com.amazon.corretto.crypto.provider.registerEdKeyFactory"));
   }
+
+  private static native byte[] computeMLDSAMuInternal(byte[] pubKeyEncoded, byte[] message);
+
+  /**
+   * Computes mu as defined on line 6 of Algorithm 7 and line 7 of Algorithm 8 in NIST FIPS 204.
+   *
+   * <p>See <a href="https://csrc.nist.gov/pubs/fips/204/final">FIPS 204</a>
+   *
+   * @param publicKey ML-DSA public key
+   * @param message byte array of the message over which to compute mu
+   * @return a byte[] of length 64 containing mu
+   */
+  static byte[] computeMLDSAMu(PublicKey publicKey, byte[] message) {
+    if (publicKey == null || !publicKey.getAlgorithm().startsWith("ML-DSA") || message == null) {
+      throw new IllegalArgumentException();
+    }
+    return computeMLDSAMuInternal(publicKey.getEncoded(), message);
+  }
 }