this.opad[i] = (byte) (key[i] ^ OPAD);
        }
        for (int i = length; i < BLOCK_LENGTH; i++) {
            this.ipad[i] = IPAD;
            this.opad[i] = OPAD;
        }

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

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

            throw new CIFSUnsupportedCryptoException(e);
        }
    }

    /**
     * Get an MD5 message digest instance.
     * @return MD5 digest instance
     */
    public static MessageDigest getMD5() {
        try {
            return MessageDigest.getInstance("MD5");
        } catch (final NoSuchAlgorithmException e) {
            throw new CIFSUnsupportedCryptoException(e);
        }
    }

    /**