// Create new Mac instance for thread safety without blocking other operations
            Mac mac;
            try {
                mac = createMacInstance();
            } catch (GeneralSecurityException e) {
                log.error("Failed to create Mac instance for signing", e);
                throw new RuntimeException("Failed to create Mac instance", e);
            }

    }
  }

  public void testMultipleUpdates() throws Exception {
    Mac mac = Mac.getInstance("HmacSHA1");
    mac.init(SHA1_KEY);
    mac.update("hello".getBytes(UTF_8));
    mac.update("world".getBytes(UTF_8));

    assertEquals(
        HashCode.fromBytes(mac.doFinal()),
        hmacSha1(SHA1_KEY).newHasher().putString("hello", UTF_8).putString("world", UTF_8).hash());
  }

        System.arraycopy(name.getBytes("US-ASCII"), 0, src, srcIndex + 13, 16);
        src[srcIndex + 28] = 0x00; // hex code
        src[srcIndex + 29] = 0x04; // flags
        // MAC address (6 bytes)
        byte[] mac = new byte[6];
        System.arraycopy(mac, 0, src, srcIndex + 31, 6);
        // Stats (6 bytes)
        byte[] stats = new byte[6];
        System.arraycopy(stats, 0, src, srcIndex + 37, 6);

   * @throws IllegalArgumentException if the given key is inappropriate for initializing this MAC
   * @since 20.0
   */
  public static HashFunction hmacMd5(Key key) {
    return new MacHashFunction("HmacMD5", key, hmacToString("hmacMd5", key));
  }

  /**
   * Returns a hash function implementing the Message Authentication Code (MAC) algorithm, using the

     * signing/verifying SMB using kerberos session key.
     * The MAC Key = concat(Session Key, Digest of Challenge);
     * Because of Kerberos Authentication don't have challenge,
     * The MAC Key = Session Key
     *
     * @param macSigningKey
     *            The MAC key used to sign or verify SMB.
     */
    public SMB1SigningDigest(final byte[] macSigningKey) {

        "darwin"  | "x64"     | VENDOR_OPENJDK      | OPENJDK_VERSION_OLD  | "Contents/Home/bin/java" | "(old version)"
        "mac"     | "x64"     | VENDOR_OPENJDK      | OPEN_JDK_VERSION     | "Contents/Home/bin/java" | ""
        "mac"     | "x64"     | VENDOR_OPENJDK      | OPENJDK_VERSION_OLD  | "Contents/Home/bin/java" | "(old version)"

	return plaintext, err
}

// MAC generates the checksum of the given req.Message using the key
// with the req.Name at the KMS.
func (k *KMS) MAC(ctx context.Context, req *MACRequest) ([]byte, error) {
	if req.Name == "" {
		req.Name = k.DefaultKey
	}

	start := time.Now()
	mac, err := k.conn.MAC(ctx, req)
	k.updateMetrics(err, time.Since(start))

	return mac, err
}

        hmac.update(serverChallenge);
        hmac.update(clientData, offset, length);
        final byte[] mac = hmac.digest();
        final byte[] ret = new byte[mac.length + clientData.length];
        System.arraycopy(mac, 0, ret, 0, mac.length);
        System.arraycopy(clientData, 0, ret, mac.length, clientData.length);
        return ret;
    }

    /**

        // Assert: overloads consistent
        assertArrayEquals(viaHash, viaPassword, "Both overloads must compute same NTLMv2 key");

        // Changing domain should change the key (domain is part of MAC input)
        byte[] differentDomain = NtlmUtil.nTOWFv2("DOMAIN", user, password);
        assertFalse(Arrays.equals(viaPassword, differentDomain), "Different domain should produce a different key");
    }

    @Test

        final byte[] seqBytes = new byte[4];
        SMBUtil.writeInt4(seqNum, seqBytes, 0);

        final MessageDigest mac = Crypto.getHMACT64(sk);
        mac.update(seqBytes); // sequence
        mac.update(data); // data
        final byte[] dgst = mac.digest();
        byte[] trunc = new byte[8];
        System.arraycopy(dgst, 0, trunc, 0, 8);

        if (log.isDebugEnabled()) {