md5.update(digest);
        try {
            return md5.digest(buf, offset, len);
        } catch (Exception ex) {
            throw new IllegalStateException();
        }
    }

    protected int engineGetDigestLength() {
        return md5.getDigestLength();
    }

    protected void engineReset() {
        md5.reset();
        md5.update(ipad);
    }

    protected void engineUpdate(byte b) {

            return this.md5.digest(buf, offset, len);
        }
        catch ( Exception ex ) {
            throw new IllegalStateException();
        }
    }


    @Override
    protected int engineGetDigestLength () {
        return this.md5.getDigestLength();
    }


    @Override
    protected void engineReset () {
        this.md5.reset();
        this.md5.update(this.ipad);
    }