invertKey();    }    /**     * <b>SPI</b>: This is the main engine method for updating data.     * <p>     * <i>in</i> and <i>out</i> may be the same array, and the input and output     * regions may overlap.     *     * @param  in           the input data.     * @param  inOffset     the offset into in specifying where the data starts.     * @param  inLen        the length of the subarray.     * @param  out          the output array.     * @param  outOffset    the offset indicating where to start writing into     *                      the out array.     * @return the number of bytes written.     * @exception CryptixException if the native library is being used, and it     *                      reports an error.     */    protected int    engineUpdate(byte[] in, int inOffset, int inLen, byte[] out, int outOffset) {        if (inLen < 0) throw new IllegalArgumentException("inLen < 0");        int blockCount = inLen / BLOCK_SIZE;        inLen = blockCount * BLOCK_SIZE;        boolean doEncrypt = (getState() == ENCRYPT);        // Avoid overlapping input and output regions.        if (in == out && (outOffset >= inOffset && outOffset < (long)inOffset+inLen ||                          inOffset >= outOffset && inOffset < (long)outOffset+inLen)) {            byte[] newin = new byte[inLen];            System.arraycopy(in, inOffset, newin, 0, inLen);            in = newin;            inOffset = 0;        }        if (native_lock != null) {            synchronized(native_lock) {                // If in == null || out == 0, evaluating their lengths will throw a                // NullPointerException.                if (inOffset < 0 || (long)inOffset + inLen > in.length ||                    outOffset < 0 || (long)outOffset + inLen > out.length)                    throw new ArrayIndexOutOfBoundsException(getAlgorithm() +                        ": Arguments to native_crypt would cause a buffer overflow");                // In future, we may pass more than one block to native_crypt to reduce                // native method overhead.                for (int i = 0; i < blockCount; i++) {                    if (0 == native_crypt(native_cookie, in, inOffset, out, outOffset,                                          doEncrypt))                        throw new CryptixException(getAlgorithm() + ": Error in native code");                    inOffset += BLOCK_SIZE;                    outOffset += BLOCK_SIZE;                }            }        } else if (doEncrypt) { // state == ENCRYPT            for (int i = 0; i < blockCount; i++) {                blockEncrypt(in, inOffset, out, outOffset);                inOffset += BLOCK_SIZE;                outOffset += BLOCK_SIZE;            }        } else {                // state == DECRYPT            for (int i = 0; i < blockCount; i++) {                blockDecrypt(in, inOffset, out, outOffset);                inOffset += BLOCK_SIZE;                outOffset += BLOCK_SIZE;            }        }        return inLen;    }// Own methods//............................................................................    /**     * Expands a user-key to a working key schedule.     * <p>     * IDEA has separate key schedules for encryption and decryption. This     * generates the encryption schedule; calling <code>invertKey</code>     * afterward will generate the decryption schedule.     *     * @param  key  the user-key object to use.     * @exception InvalidKeyException if one of the following occurs: <ul>     *                <li> key.getEncoded() == null;     *                <li> The length of the user key array is outside the     *                     permissible limits.     *              </ul>     * @exception CryptixException if a self-test fails.     */    private void makeKey(Key key)    throws InvalidKeyException, CryptixException {        byte[] userkey = key.getEncoded();        if (userkey == null)            throw new InvalidKeyException(getAlgorithm() + ": Null user key");        if (userkey.length != KEY_LENGTH)            throw new InvalidKeyException(getAlgorithm() + ": Invalid user key length");        // If native library available then use it. If not or if        // native method returned error then revert to 100% Java.        if (native_lock != null) {            synchronized(native_lock) {                try {                    linkStatus.check(native_ks(native_cookie, userkey));                    return;                } catch (Error error) {                    native_finalize();                    native_lock = null;if (DEBUG && debuglevel > 0) debug(error + ". Will use 100% Java.");                }            }        }        /*         * Expand user key of 128 bits to full 832 bits of encryption key.         */        ks[0] = (short)((userkey[ 0] & 0xFF) << 8 | (userkey[ 1] & 0xFF));        ks[1] = (short)((userkey[ 2] & 0xFF) << 8 | (userkey[ 3] & 0xFF));        ks[2] = (short)((userkey[ 4] & 0xFF) << 8 | (userkey[ 5] & 0xFF));        ks[3] = (short)((userkey[ 6] & 0xFF) << 8 | (userkey[ 7] & 0xFF));        ks[4] = (short)((userkey[ 8] & 0xFF) << 8 | (userkey[ 9] & 0xFF));        ks[5] = (short)((userkey[10] & 0xFF) << 8 | (userkey[11] & 0xFF));        ks[6] = (short)((userkey[12] & 0xFF) << 8 | (userkey[13] & 0xFF));        ks[7] = (short)((userkey[14] & 0xFF) << 8 | (userkey[15] & 0xFF));        for (int i = 0, zoff = 0, j = 8; j < INTERNAL_KEY_LENGTH; i &= 7, j++) {            i++;            ks[i + 7 + zoff] = (short)((ks[(i & 7) + zoff] << 9) |                ((ks[((i + 1) & 7) + zoff] >>> 7) & 0x1FF));            zoff += i & 8;        }    }    /**     * IDEA, being a symmetric cipher, uses the same algorithm for both     * encryption and decryption. What changes is the key. For the inverse     * operation (of either encryption or decryption) the following method     * inverts the key to make it ready for application of the cipher method.     */    private void invertKey () {        if (native_lock == null) {            int i, j = 4, k = INTERNAL_KEY_LENGTH - 1;            short[] temp = new short[INTERNAL_KEY_LENGTH];            temp[k--] = inv(ks[3]);            temp[k--] = (short) -ks[2];            temp[k--] = (short) -ks[1];            temp[k--] = inv(ks[0]);            for (i = 1; i < ROUNDS; i++, j += 6) {                temp[k--] = ks[j + 1];                temp[k--] = ks[j];                temp[k--] = inv(ks[j + 5]);                temp[k--] = (short) -ks[j + 3];                temp[k--] = (short) -ks[j + 4];                temp[k--] = inv(ks[j + 2]);            }            temp[k--] = ks[j + 1];            temp[k--] = ks[j];            temp[k--] = inv(ks[j + 5]);            temp[k--] = (short) -ks[j + 4];            temp[k--] = (short) -ks[j + 3];            temp[k--] = inv(ks[j + 2]);            System.arraycopy(temp, 0, ks, 0, INTERNAL_KEY_LENGTH);        }    }    /**     * IDEA encryption/decryption algorithm using the current key schedule.     *     * @param  in       an array containing the plaintext block     * @param  inOffset the starting offset of the plaintext block     * @param  out      an array containing the ciphertext block     * @param  inOffset the starting offset of the ciphertext block     */    private void blockEncrypt (byte[] in, int inOffset, byte[] out, int outOffset) {        short            x1 = (short)(((in[inOffset++] & 0xFF) << 8) | (in[inOffset++] & 0xFF)),            x2 = (short)(((in[inOffset++] & 0xFF) << 8) | (in[inOffset++] & 0xFF)),            x3 = (short)(((in[inOffset++] & 0xFF) << 8) | (in[inOffset++] & 0xFF)),            x4 = (short)(((in[inOffset++] & 0xFF) << 8) | (in[inOffset  ] & 0xFF)),            s2, s3;        int i = 0,            round = ROUNDS;        while (round-- > 0) {            x1 = mul(x1, ks[i++]);            x2 += ks[i++];            x3 += ks[i++];            x4 = mul(x4, ks[i++]);            s3 = x3;            x3 = mul(x1 ^ x3, ks[i++]);            s2 = x2;            x2 = mul(x3 + (x2 ^ x4), ks[i++]);            x3 += x2;            x1 ^= x2;            x4 ^= x3;            x2 ^= s3;            x3 ^= s2;        }        s2 = mul(x1, ks[i++]);        out[outOffset++] = (byte)(s2 >>> 8);        out[outOffset++] = (byte) s2;        s2 = (short)(x3 + ks[i++]);        out[outOffset++] = (byte)(s2 >>> 8);        out[outOffset++] = (byte) s2;        s2 = (short)(x2 + ks[i++]);        out[outOffset++] = (byte)(s2 >>> 8);        out[outOffset++] = (byte) s2;        s2 = mul(x4, ks[i]);        out[outOffset++] = (byte)(s2 >>> 8);        out[outOffset  ] = (byte) s2;    }    /**     * IDEA uses the same algorithm for both encryption and decryption. Only the     * key schedule changes.     */    private void blockDecrypt (byte[] in, int inOffset, byte[] out, int outOffset) {        blockEncrypt(in, inOffset, out, outOffset);    }    /**     * Multiplication modulo (2**16)+1.     */    private static short mul (int a, int b) {        a &= 0xFFFF;        b &= 0xFFFF;        int p;        if (a != 0) {            if (b != 0) {                p = a * b;                b = p & 0xFFFF;                a = p >>> 16;                return (short)(b - a + (b < a ? 1 : 0));            } else                return (short)(1 - a);        } else            return (short)(1 - b);    }    /**     * Compute inverse of x, modulo (2**16)+1, using Euclidean gcd algorithm.     *     * The Euclidean part of this algorithm could live in a     * general purpose math library, but then it would probably     * end up too slow.     */    private static short inv (short xx) {        int x = xx & 0xFFFF;       // only lower 16 bits        if (x <= 1)            return (short)x;        // 0 and 1 are self-inverse        int t1 = 0x10001 / x;        // Since x >= 2, this fits into 16 bits        int y = 0x10001 % x;        if (y == 1)            return (short)(1 - t1);        int t0 = 1;        int q;        do {            q = x / y;            x = x % y;            t0 += q * t1;            if (x == 1)                return (short)t0;            q = y / x;            y %= x;            t1 += q * t0;        } while (y != 1);        return (short)(1 - t1);    }// Test methods//................................................................................//// Don't expand this code please without thinking about it,// much better to write a separate program.    /**     * Entry point for very basic <code>self_test</code>.     */    public static void    main(String argv[])     {        try { self_test(); }        catch(Throwable t) { t.printStackTrace(); }    }    //    // This is (apparently) the official certification data.    // Use ints as Java grumbles about negative hex values.    //    static final private byte[][][] tests =    {      { // cert 1        { 0, 1, 0, 2, 0, 3, 0, 4, 0, 5, 0, 6, 0, 7, 0, 8},  // key        { 0, 0, 0, 1, 0, 2, 0, 3},                          // plain        { 17, -5, -19, 43, 1, -104, 109, -27},              // cipher      },      { // cert 8        { 58, -104, 78, 32, 0, 25, 93, -77, 46, -27, 1, -56, -60, 124, -22, 96},        { 1, 2, 3, 4, 5, 6, 7, 8},        { -105, -68, -40, 32, 7, -128, -38, -122},      },      { // cert 9        { 0, 100, 0, -56, 1, 44, 1, -112, 1, -12, 2, 88, 2, -68, 3, 32},  // key        { 5, 50, 10, 100, 20, -56, 25, -6},                               // plain        { 101, -66, -121, -25, -94, 83, -118, -19},                       // cipher      },    };    /**     * Do some basic tests.     * Three of the certification data are included only, no output,     * success or exception.     * If you want more, write a test program!     * @see cryptix.examples.IDEA     */    public static void self_test()    throws Throwable {        Cipher cryptor = Cipher.getInstance("IDEA", "Cryptix");        RawSecretKey userKey;        byte[] tmp;        for (int i = 0; i < tests.length; i++) {            userKey = new RawSecretKey("IDEA", tests[i][0]);            cryptor.initEncrypt(userKey);            tmp = cryptor.crypt(tests[i][1]);            if (!ArrayUtil.areEqual(tests[i][2], tmp))                throw new CryptixException("encrypt #"+ i +" failed");            cryptor.initDecrypt(userKey);            tmp = cryptor.crypt(tests[i][2]);            if (!ArrayUtil.areEqual(tests[i][1], tmp))                throw new CryptixException("decrypt #"+ i +" failed");        }if (DEBUG && debuglevel > 0) debug("Self-test OK");    }}