ipad[i] = IPAD;
            opad[i] = OPAD;
        }
        try {
            md5 = MessageDigest.getInstance("MD5");
        } catch (Exception ex) {
            throw new IllegalStateException(ex.getMessage());
        }
        engineReset();
    }

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

    }


    @Override
    public Object clone () {
        try {
            return new HMACT64(this);
        }
        catch ( CloneNotSupportedException ex ) {
            throw new IllegalStateException(ex.getMessage());
        }
    }


    @Override
    protected byte[] engineDigest () {
        byte[] digest = this.md5.digest();
        this.md5.update(this.opad);