}
    }

    // Integration test with actual MD5 to verify HMAC calculation logic
    @Test
    void testHMACT64WithActualMD5() throws NoSuchAlgorithmException {
        // This test uses a real MD5 instance to verify the HMAC calculation logic
        // HMACT64 is a modified HMAC-MD5 where the key is truncated at 64 bytes
        // instead of being hashed when it exceeds the block size.

	streamingContentSHA256        = "STREAMING-AWS4-HMAC-SHA256-PAYLOAD"
	streamingContentSHA256Trailer = "STREAMING-AWS4-HMAC-SHA256-PAYLOAD-TRAILER"
	signV4ChunkedAlgorithm        = "AWS4-HMAC-SHA256-PAYLOAD"
	signV4ChunkedAlgorithmTrailer = "AWS4-HMAC-SHA256-TRAILER"
	streamingContentEncoding      = "aws-chunked"
	awsTrailerHeader              = "X-Amz-Trailer"

        HMACT64 hmac = new HMACT64(TEST_KEY);
        // MD5 digest length is 16 bytes
        assertEquals(16, hmac.engineGetDigestLength());
    }

    @Test
    void testEngineDigest() {
        // Test engineDigest()
        HMACT64 hmac = new HMACT64(TEST_KEY);
        hmac.engineUpdate(TEST_DATA, 0, TEST_DATA.length);
        byte[] result = hmac.engineDigest();

        assertNotNull(result);

 * supporting various checksum algorithms including HMAC-MD5 and HMAC-SHA1 with AES.
 */
public class PacSignature {

    /**
     * Kerberos checksum type for HMAC-MD5 (ARCFOUR-HMAC).
     */
    public static final int KERB_CHECKSUM_HMAC_MD5 = 0xFFFFFF76;
    /**
     * Kerberos checksum type for HMAC-SHA1-96 with AES-128.
     */
    public static final int HMAC_SHA1_96_AES128 = 0x0000000F;

		{
			policy:  `{"conditions":[["eq","$bucket","asdf"],["eq","$key","hello.txt"]],"conditions":[["eq","$success_action_status","201"],["eq","$Content-Type","plain/text"],["eq","$success_action_status","201"],["eq","$x-amz-algorithm","AWS4-HMAC-SHA256"],["eq","$x-amz-credential","Q3AM3UQ867SPQQA43P2F/20210315/us-east-1/s3/aws4_request"],["eq","$x-amz-date","20210315T091621Z"]]}`,
			success: false,
		},
		// invalid json.
		{

 * ARCFOUR-HMAC-MD5 and AES-based HMAC algorithms.
 */
public class PacMac {

    /**
     * Private constructor to prevent instantiation of utility class.
     */
    private PacMac() {
        // Utility class
    }

    /**
     *
     */
    private static final String HMAC_KEY = "HMAC";

// This is based on RFC 4253, section 6.4, but with hmac-md5 variants removed
// because they have reached the end of their useful life.
// https://cs.opensource.google/go/x/crypto/+/refs/tags/v0.22.0:ssh/common.go;l=85
var supportedMACs = []string{
	"hmac******@****.***", "hmac******@****.***", "hmac-sha2-256", "hmac-sha2-512", "hmac-sha1", "hmac-sha1-96",
}

e9dQpeeEJWgKUa/8R61oCy1mFwIg==", "X-Minio-Internal-Server-Side-Encryption-S3-Sealed-Key": "IAAfAPFYRDkHVirJBJxBixNj3PLWt78dFuUTyTLIdLG820J7XqLPBO4gpEEEWw/DoTsJIb+apnaem+rKtQ1h3Q==", "X-Minio-Internal-Server-Side-Encryption-Seal-Algorithm": "DAREv2-HMAC-SHA256", "content-type": "application/octet-stream", "etag": "20000f00e2c3709dc94905c6ce31e1cadbd1c064e14acdcd44cf0ac2db777eeedd88d639fcd64de16851ade8b21a9a1a"}, Parts: []ObjectPartInfo{{ETag: "", Number: 1, Size: 3430, ActualSize: 3398}}, Erasure:...

        }

        this.md5 = Crypto.getMD5();
        engineReset();
    }

    private HMACT64(final HMACT64 hmac) throws CloneNotSupportedException {
        super("HMACT64");
        this.ipad = hmac.ipad;
        this.opad = hmac.opad;
        this.md5 = (MessageDigest) hmac.md5.clone();
    }

    @Override
    public Object clone() {
        try {
            return new HMACT64(this);

            throw new IllegalStateException(ex.getMessage());
        }
        engineReset();
    }

    private HMACT64(final HMACT64 hmac) throws CloneNotSupportedException {
        super("HMACT64");
        this.ipad = hmac.ipad;
        this.opad = hmac.opad;
        this.md5 = (MessageDigest) hmac.md5.clone();
    }

    @Override
    public Object clone() {
        try {
            return new HMACT64(this);