package org.bouncycastle.crypto.engines;import org.bouncycastle.crypto.BlockCipher;import org.bouncycastle.crypto.CipherParameters;import org.bouncycastle.crypto.DataLengthException;import org.bouncycastle.crypto.params.KeyParameter;/** * A class that provides Twofish encryption operations. * * This Java implementation is based on the Java reference * implementation provided by Bruce Schneier and developed * by Raif S. Naffah. */public final class TwofishEngine    implements BlockCipher{    private static final byte[][] P =  {    {  // p0        (byte) 0xA9, (byte) 0x67, (byte) 0xB3, (byte) 0xE8,        (byte) 0x04, (byte) 0xFD, (byte) 0xA3, (byte) 0x76,        (byte) 0x9A, (byte) 0x92, (byte) 0x80, (byte) 0x78,        (byte) 0xE4, (byte) 0xDD, (byte) 0xD1, (byte) 0x38,        (byte) 0x0D, (byte) 0xC6, (byte) 0x35, (byte) 0x98,        (byte) 0x18, (byte) 0xF7, (byte) 0xEC, (byte) 0x6C,        (byte) 0x43, (byte) 0x75, (byte) 0x37, (byte) 0x26,        (byte) 0xFA, (byte) 0x13, (byte) 0x94, (byte) 0x48,        (byte) 0xF2, (byte) 0xD0, (byte) 0x8B, (byte) 0x30,        (byte) 0x84, (byte) 0x54, (byte) 0xDF, (byte) 0x23,        (byte) 0x19, (byte) 0x5B, (byte) 0x3D, (byte) 0x59,        (byte) 0xF3, (byte) 0xAE, (byte) 0xA2, (byte) 0x82,        (byte) 0x63, (byte) 0x01, (byte) 0x83, (byte) 0x2E,        (byte) 0xD9, (byte) 0x51, (byte) 0x9B, (byte) 0x7C,        (byte) 0xA6, (byte) 0xEB, (byte) 0xA5, (byte) 0xBE,        (byte) 0x16, (byte) 0x0C, (byte) 0xE3, (byte) 0x61,        (byte) 0xC0, (byte) 0x8C, (byte) 0x3A, (byte) 0xF5,        (byte) 0x73, (byte) 0x2C, (byte) 0x25, (byte) 0x0B,        (byte) 0xBB, (byte) 0x4E, (byte) 0x89, (byte) 0x6B,        (byte) 0x53, (byte) 0x6A, (byte) 0xB4, (byte) 0xF1,        (byte) 0xE1, (byte) 0xE6, (byte) 0xBD, (byte) 0x45,        (byte) 0xE2, (byte) 0xF4, (byte) 0xB6, (byte) 0x66,        (byte) 0xCC, (byte) 0x95, (byte) 0x03, (byte) 0x56,        (byte) 0xD4, (byte) 0x1C, (byte) 0x1E, (byte) 0xD7,        (byte) 0xFB, (byte) 0xC3, (byte) 0x8E, (byte) 0xB5,        (byte) 0xE9, (byte) 0xCF, (byte) 0xBF, (byte) 0xBA,        (byte) 0xEA, (byte) 0x77, (byte) 0x39, (byte) 0xAF,        (byte) 0x33, (byte) 0xC9, (byte) 0x62, (byte) 0x71,        (byte) 0x81, (byte) 0x79, (byte) 0x09, (byte) 0xAD,        (byte) 0x24, (byte) 0xCD, (byte) 0xF9, (byte) 0xD8,        (byte) 0xE5, (byte) 0xC5, (byte) 0xB9, (byte) 0x4D,        (byte) 0x44, (byte) 0x08, (byte) 0x86, (byte) 0xE7,        (byte) 0xA1, (byte) 0x1D, (byte) 0xAA, (byte) 0xED,        (byte) 0x06, (byte) 0x70, (byte) 0xB2, (byte) 0xD2,        (byte) 0x41, (byte) 0x7B, (byte) 0xA0, (byte) 0x11,        (byte) 0x31, (byte) 0xC2, (byte) 0x27, (byte) 0x90,        (byte) 0x20, (byte) 0xF6, (byte) 0x60, (byte) 0xFF,        (byte) 0x96, (byte) 0x5C, (byte) 0xB1, (byte) 0xAB,        (byte) 0x9E, (byte) 0x9C, (byte) 0x52, (byte) 0x1B,        (byte) 0x5F, (byte) 0x93, (byte) 0x0A, (byte) 0xEF,        (byte) 0x91, (byte) 0x85, (byte) 0x49, (byte) 0xEE,        (byte) 0x2D, (byte) 0x4F, (byte) 0x8F, (byte) 0x3B,        (byte) 0x47, (byte) 0x87, (byte) 0x6D, (byte) 0x46,        (byte) 0xD6, (byte) 0x3E, (byte) 0x69, (byte) 0x64,        (byte) 0x2A, (byte) 0xCE, (byte) 0xCB, (byte) 0x2F,        (byte) 0xFC, (byte) 0x97, (byte) 0x05, (byte) 0x7A,        (byte) 0xAC, (byte) 0x7F, (byte) 0xD5, (byte) 0x1A,        (byte) 0x4B, (byte) 0x0E, (byte) 0xA7, (byte) 0x5A,        (byte) 0x28, (byte) 0x14, (byte) 0x3F, (byte) 0x29,        (byte) 0x88, (byte) 0x3C, (byte) 0x4C, (byte) 0x02,        (byte) 0xB8, (byte) 0xDA, (byte) 0xB0, (byte) 0x17,        (byte) 0x55, (byte) 0x1F, (byte) 0x8A, (byte) 0x7D,        (byte) 0x57, (byte) 0xC7, (byte) 0x8D, (byte) 0x74,        (byte) 0xB7, (byte) 0xC4, (byte) 0x9F, (byte) 0x72,        (byte) 0x7E, (byte) 0x15, (byte) 0x22, (byte) 0x12,        (byte) 0x58, (byte) 0x07, (byte) 0x99, (byte) 0x34,        (byte) 0x6E, (byte) 0x50, (byte) 0xDE, (byte) 0x68,        (byte) 0x65, (byte) 0xBC, (byte) 0xDB, (byte) 0xF8,        (byte) 0xC8, (byte) 0xA8, (byte) 0x2B, (byte) 0x40,        (byte) 0xDC, (byte) 0xFE, (byte) 0x32, (byte) 0xA4,        (byte) 0xCA, (byte) 0x10, (byte) 0x21, (byte) 0xF0,        (byte) 0xD3, (byte) 0x5D, (byte) 0x0F, (byte) 0x00,        (byte) 0x6F, (byte) 0x9D, (byte) 0x36, (byte) 0x42,        (byte) 0x4A, (byte) 0x5E, (byte) 0xC1, (byte) 0xE0 },    {  // p1        (byte) 0x75, (byte) 0xF3, (byte) 0xC6, (byte) 0xF4,        (byte) 0xDB, (byte) 0x7B, (byte) 0xFB, (byte) 0xC8,        (byte) 0x4A, (byte) 0xD3, (byte) 0xE6, (byte) 0x6B,        (byte) 0x45, (byte) 0x7D, (byte) 0xE8, (byte) 0x4B,        (byte) 0xD6, (byte) 0x32, (byte) 0xD8, (byte) 0xFD,        (byte) 0x37, (byte) 0x71, (byte) 0xF1, (byte) 0xE1,        (byte) 0x30, (byte) 0x0F, (byte) 0xF8, (byte) 0x1B,        (byte) 0x87, (byte) 0xFA, (byte) 0x06, (byte) 0x3F,        (byte) 0x5E, (byte) 0xBA, (byte) 0xAE, (byte) 0x5B,        (byte) 0x8A, (byte) 0x00, (byte) 0xBC, (byte) 0x9D,        (byte) 0x6D, (byte) 0xC1, (byte) 0xB1, (byte) 0x0E,        (byte) 0x80, (byte) 0x5D, (byte) 0xD2, (byte) 0xD5,        (byte) 0xA0, (byte) 0x84, (byte) 0x07, (byte) 0x14,        (byte) 0xB5, (byte) 0x90, (byte) 0x2C, (byte) 0xA3,        (byte) 0xB2, (byte) 0x73, (byte) 0x4C, (byte) 0x54,        (byte) 0x92, (byte) 0x74, (byte) 0x36, (byte) 0x51,        (byte) 0x38, (byte) 0xB0, (byte) 0xBD, (byte) 0x5A,        (byte) 0xFC, (byte) 0x60, (byte) 0x62, (byte) 0x96,        (byte) 0x6C, (byte) 0x42, (byte) 0xF7, (byte) 0x10,        (byte) 0x7C, (byte) 0x28, (byte) 0x27, (byte) 0x8C,        (byte) 0x13, (byte) 0x95, (byte) 0x9C, (byte) 0xC7,        (byte) 0x24, (byte) 0x46, (byte) 0x3B, (byte) 0x70,        (byte) 0xCA, (byte) 0xE3, (byte) 0x85, (byte) 0xCB,        (byte) 0x11, (byte) 0xD0, (byte) 0x93, (byte) 0xB8,        (byte) 0xA6, (byte) 0x83, (byte) 0x20, (byte) 0xFF,        (byte) 0x9F, (byte) 0x77, (byte) 0xC3, (byte) 0xCC,        (byte) 0x03, (byte) 0x6F, (byte) 0x08, (byte) 0xBF,        (byte) 0x40, (byte) 0xE7, (byte) 0x2B, (byte) 0xE2,        (byte) 0x79, (byte) 0x0C, (byte) 0xAA, (byte) 0x82,        (byte) 0x41, (byte) 0x3A, (byte) 0xEA, (byte) 0xB9,        (byte) 0xE4, (byte) 0x9A, (byte) 0xA4, (byte) 0x97,        (byte) 0x7E, (byte) 0xDA, (byte) 0x7A, (byte) 0x17,        (byte) 0x66, (byte) 0x94, (byte) 0xA1, (byte) 0x1D,        (byte) 0x3D, (byte) 0xF0, (byte) 0xDE, (byte) 0xB3,        (byte) 0x0B, (byte) 0x72, (byte) 0xA7, (byte) 0x1C,        (byte) 0xEF, (byte) 0xD1, (byte) 0x53, (byte) 0x3E,        (byte) 0x8F, (byte) 0x33, (byte) 0x26, (byte) 0x5F,        (byte) 0xEC, (byte) 0x76, (byte) 0x2A, (byte) 0x49,        (byte) 0x81, (byte) 0x88, (byte) 0xEE, (byte) 0x21,        (byte) 0xC4, (byte) 0x1A, (byte) 0xEB, (byte) 0xD9,        (byte) 0xC5, (byte) 0x39, (byte) 0x99, (byte) 0xCD,        (byte) 0xAD, (byte) 0x31, (byte) 0x8B, (byte) 0x01,        (byte) 0x18, (byte) 0x23, (byte) 0xDD, (byte) 0x1F,        (byte) 0x4E, (byte) 0x2D, (byte) 0xF9, (byte) 0x48,        (byte) 0x4F, (byte) 0xF2, (byte) 0x65, (byte) 0x8E,        (byte) 0x78, (byte) 0x5C, (byte) 0x58, (byte) 0x19,        (byte) 0x8D, (byte) 0xE5, (byte) 0x98, (byte) 0x57,        (byte) 0x67, (byte) 0x7F, (byte) 0x05, (byte) 0x64,        (byte) 0xAF, (byte) 0x63, (byte) 0xB6, (byte) 0xFE,        (byte) 0xF5, (byte) 0xB7, (byte) 0x3C, (byte) 0xA5,        (byte) 0xCE, (byte) 0xE9, (byte) 0x68, (byte) 0x44,        (byte) 0xE0, (byte) 0x4D, (byte) 0x43, (byte) 0x69,        (byte) 0x29, (byte) 0x2E, (byte) 0xAC, (byte) 0x15,        (byte) 0x59, (byte) 0xA8, (byte) 0x0A, (byte) 0x9E,        (byte) 0x6E, (byte) 0x47, (byte) 0xDF, (byte) 0x34,        (byte) 0x35, (byte) 0x6A, (byte) 0xCF, (byte) 0xDC,        (byte) 0x22, (byte) 0xC9, (byte) 0xC0, (byte) 0x9B,        (byte) 0x89, (byte) 0xD4, (byte) 0xED, (byte) 0xAB,        (byte) 0x12, (byte) 0xA2, (byte) 0x0D, (byte) 0x52,        (byte) 0xBB, (byte) 0x02, (byte) 0x2F, (byte) 0xA9,        (byte) 0xD7, (byte) 0x61, (byte) 0x1E, (byte) 0xB4,        (byte) 0x50, (byte) 0x04, (byte) 0xF6, (byte) 0xC2,        (byte) 0x16, (byte) 0x25, (byte) 0x86, (byte) 0x56,        (byte) 0x55, (byte) 0x09, (byte) 0xBE, (byte) 0x91  }    };    /**    * Define the fixed p0/p1 permutations used in keyed S-box lookup.    * By changing the following constant definitions, the S-boxes will    * automatically get changed in the Twofish engine.    */    private static final int P_00 = 1;    private static final int P_01 = 0;    private static final int P_02 = 0;    private static final int P_03 = P_01 ^ 1;    private static final int P_04 = 1;    private static final int P_10 = 0;    private static final int P_11 = 0;    private static final int P_12 = 1;    private static final int P_13 = P_11 ^ 1;    private static final int P_14 = 0;    private static final int P_20 = 1;    private static final int P_21 = 1;    private static final int P_22 = 0;    private static final int P_23 = P_21 ^ 1;    private static final int P_24 = 0;    private static final int P_30 = 0;    private static final int P_31 = 1;    private static final int P_32 = 1;    private static final int P_33 = P_31 ^ 1;    private static final int P_34 = 1;    /* Primitive polynomial for GF(256) */    private static final int GF256_FDBK =   0x169;    private static final int GF256_FDBK_2 = GF256_FDBK / 2;    private static final int GF256_FDBK_4 = GF256_FDBK / 4;    private static final int RS_GF_FDBK = 0x14D; // field generator    //====================================    // Useful constants    //====================================    private static final int    ROUNDS = 16;    private static final int    MAX_ROUNDS = 16;  // bytes = 128 bits    private static final int    BLOCK_SIZE = 16;  // bytes = 128 bits    private static final int    MAX_KEY_BITS = 256;    private static final int    INPUT_WHITEN=0;    private static final int    OUTPUT_WHITEN=INPUT_WHITEN+BLOCK_SIZE/4; // 4    private static final int    ROUND_SUBKEYS=OUTPUT_WHITEN+BLOCK_SIZE/4;// 8    private static final int    TOTAL_SUBKEYS=ROUND_SUBKEYS+2*MAX_ROUNDS;// 40    private static final int    SK_STEP = 0x02020202;    private static final int    SK_BUMP = 0x01010101;    private static final int    SK_ROTL = 9;    private boolean encrypting = false;    private int[] gMDS0 = new int[MAX_KEY_BITS];    private int[] gMDS1 = new int[MAX_KEY_BITS];    private int[] gMDS2 = new int[MAX_KEY_BITS];    private int[] gMDS3 = new int[MAX_KEY_BITS];    /**     * gSubKeys[] and gSBox[] are eventually used in the      * encryption and decryption methods.     */    private int[] gSubKeys;    private int[] gSBox;    private int k64Cnt = 0;    private byte[] workingKey = null;    public TwofishEngine()    {        // calculate the MDS matrix        int[] m1 = new int[2];        int[] mX = new int[2];        int[] mY = new int[2];        int j;        for (int i=0; i< MAX_KEY_BITS ; i++)        {            j = P[0][i] & 0xff;            m1[0] = j;            mX[0] = Mx_X(j) & 0xff;            mY[0] = Mx_Y(j) & 0xff;            j = P[1][i] & 0xff;            m1[1] = j;            mX[1] = Mx_X(j) & 0xff;            mY[1] = Mx_Y(j) & 0xff;            gMDS0[i] = m1[P_00]       | mX[P_00] <<  8 |                         mY[P_00] << 16 | mY[P_00] << 24;            gMDS1[i] = mY[P_10]       | mY[P_10] <<  8 |                         mX[P_10] << 16 | m1[P_10] << 24;            gMDS2[i] = mX[P_20]       | mY[P_20] <<  8 |                         m1[P_20] << 16 | mY[P_20] << 24;            gMDS3[i] = mX[P_30]       | m1[P_30] <<  8 |                         mY[P_30] << 16 | mX[P_30] << 24;        }    }    /**     * initialise a Twofish cipher.     *     * @param encrypting whether or not we are for encryption.     * @param params the parameters required to set up the cipher.     * @exception IllegalArgumentException if the params argument is     * inappropriate.     */    public void init(        boolean             encrypting,        CipherParameters    params)    {        if (params instanceof KeyParameter)        {            this.encrypting = encrypting;            this.workingKey = ((KeyParameter)params).getKey();            this.k64Cnt = (this.workingKey.length / 8); // pre-padded ?            setKey(this.workingKey);            return;        }        throw new IllegalArgumentException("invalid parameter passed to Twofish init - " + params.getClass().getName());    }    public String getAlgorithmName()    {        return "Twofish";    }    public final int processBlock(        byte[] in,        int inOff,        byte[] out,        int outOff)    {        if (workingKey == null)        {            throw new IllegalStateException("Twofish not initialised");        }        if ((inOff + BLOCK_SIZE) > in.length)        {            throw new DataLengthException("input buffer too short");        }        if ((outOff + BLOCK_SIZE) > out.length)        {            throw new DataLengthException("output buffer too short");        }        if (encrypting)        {            encryptBlock(in, inOff, out, outOff);        }        else        {                decryptBlock(in, inOff, out, outOff);        }        return BLOCK_SIZE;    }    public void reset()    {        if (this.workingKey != null)        {            setKey(this.workingKey);        }    }    public int getBlockSize()    {        return BLOCK_SIZE;    }    //==================================    // Private Implementation    //==================================    private void setKey(byte[] key)    {