public static MessageDigest getHMACT64 ( byte[] key ) {
        return new HMACT64(key);
    }


    /**
     * 
     * @param key
     * @return RC4 cipher
     */
    public static Cipher getArcfour ( byte[] key ) {
        try {
            Cipher c = Cipher.getInstance("RC4");
            c.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(key, "RC4"));
            return c;
        }
        catch (

        this.sealClientHandle = Crypto.getArcfour(this.sealClientKey);
        if ( log.isDebugEnabled() ) {
            log.debug("Seal key is " + Hexdump.toHexString(this.sealClientKey));
        }

        this.sealServerKey = deriveKey(mk, S2C_SEAL_CONSTANT);
        this.sealServerHandle = Crypto.getArcfour(this.sealServerKey);

        if ( log.isDebugEnabled() ) {

                    tc.getConfig().getRandom().nextBytes(this.masterKey);

                    byte[] exchangedKey = new byte[16];
                    Cipher arcfour = Crypto.getArcfour(ntlm2SessionKey);
                    arcfour.update(this.masterKey, 0, 16, exchangedKey, 0);
                    setEncryptedSessionKey(exchangedKey);
                }
                else {