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 a basic DES engine. */public class DESEngine    implements BlockCipher{    protected static final int  BLOCK_SIZE = 8;    private int[]               workingKey = null;    /**     * standard constructor.     */    public DESEngine()    {    }    /**     * initialise a DES 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)        {            if (((KeyParameter)params).getKey().length > 8)            {                throw new IllegalArgumentException("DES key too long - should be 8 bytes");            }                        workingKey = generateWorkingKey(encrypting,                                  ((KeyParameter)params).getKey());            return;        }        throw new IllegalArgumentException("invalid parameter passed to DES init - " + params.getClass().getName());    }    public String getAlgorithmName()    {        return "DES";    }    public int getBlockSize()    {        return BLOCK_SIZE;    }    public int processBlock(        byte[] in,        int inOff,        byte[] out,        int outOff)    {        if (workingKey == null)        {            throw new IllegalStateException("DES engine 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");        }        desFunc(workingKey, in, inOff, out, outOff);        return BLOCK_SIZE;    }    public void reset()    {    }    /**     * what follows is mainly taken from "Applied Cryptography", by     * Bruce Schneier, however it also bears great resemblance to Richard     * Outerbridge's D3DES...     */    static short[]    Df_Key =        {            0x01,0x23,0x45,0x67,0x89,0xab,0xcd,0xef,            0xfe,0xdc,0xba,0x98,0x76,0x54,0x32,0x10,            0x89,0xab,0xcd,0xef,0x01,0x23,0x45,0x67        };    static short[]    bytebit =        {            0200, 0100, 040, 020, 010, 04, 02, 01        };    static int[]    bigbyte =        {            0x800000, 0x400000, 0x200000, 0x100000,            0x80000,  0x40000,  0x20000,  0x10000,            0x8000,      0x4000,   0x2000,   0x1000,            0x800,    0x400,    0x200,    0x100,            0x80,      0x40,        0x20,     0x10,            0x8,      0x4,      0x2,      0x1        };    /*     * Use the key schedule specified in the Standard (ANSI X3.92-1981).     */    static byte[]    pc1 =        {            56, 48, 40, 32, 24, 16,  8,   0, 57, 49, 41, 33, 25, 17,             9,  1, 58, 50, 42, 34, 26,  18, 10,  2, 59, 51, 43, 35,            62, 54, 46, 38, 30, 22, 14,   6, 61, 53, 45, 37, 29, 21,            13,  5, 60, 52, 44, 36, 28,  20, 12,  4, 27, 19, 11,  3        };    static byte[] totrot =        {            1, 2, 4, 6, 8, 10, 12, 14,            15, 17, 19, 21, 23, 25, 27, 28        };    static byte[] pc2 =        {            13, 16, 10, 23,  0,  4,  2, 27, 14,  5, 20,  9,            22, 18, 11,  3, 25,  7, 15,  6, 26, 19, 12,  1,            40, 51, 30, 36, 46, 54, 29, 39, 50, 44, 32, 47,            43, 48, 38, 55, 33, 52, 45, 41, 49, 35, 28, 31        };    static int[] SP1 = {        0x01010400, 0x00000000, 0x00010000, 0x01010404,        0x01010004, 0x00010404, 0x00000004, 0x00010000,        0x00000400, 0x01010400, 0x01010404, 0x00000400,        0x01000404, 0x01010004, 0x01000000, 0x00000004,        0x00000404, 0x01000400, 0x01000400, 0x00010400,        0x00010400, 0x01010000, 0x01010000, 0x01000404,        0x00010004, 0x01000004, 0x01000004, 0x00010004,        0x00000000, 0x00000404, 0x00010404, 0x01000000,        0x00010000, 0x01010404, 0x00000004, 0x01010000,        0x01010400, 0x01000000, 0x01000000, 0x00000400,        0x01010004, 0x00010000, 0x00010400, 0x01000004,        0x00000400, 0x00000004, 0x01000404, 0x00010404,        0x01010404, 0x00010004, 0x01010000, 0x01000404,        0x01000004, 0x00000404, 0x00010404, 0x01010400,        0x00000404, 0x01000400, 0x01000400, 0x00000000,        0x00010004, 0x00010400, 0x00000000, 0x01010004    };    static int[] SP2 = {        0x80108020, 0x80008000, 0x00008000, 0x00108020,        0x00100000, 0x00000020, 0x80100020, 0x80008020,        0x80000020, 0x80108020, 0x80108000, 0x80000000,        0x80008000, 0x00100000, 0x00000020, 0x80100020,        0x00108000, 0x00100020, 0x80008020, 0x00000000,        0x80000000, 0x00008000, 0x00108020, 0x80100000,        0x00100020, 0x80000020, 0x00000000, 0x00108000,        0x00008020, 0x80108000, 0x80100000, 0x00008020,        0x00000000, 0x00108020, 0x80100020, 0x00100000,        0x80008020, 0x80100000, 0x80108000, 0x00008000,        0x80100000, 0x80008000, 0x00000020, 0x80108020,        0x00108020, 0x00000020, 0x00008000, 0x80000000,        0x00008020, 0x80108000, 0x00100000, 0x80000020,        0x00100020, 0x80008020, 0x80000020, 0x00100020,        0x00108000, 0x00000000, 0x80008000, 0x00008020,        0x80000000, 0x80100020, 0x80108020, 0x00108000    };    static int[] SP3 = {        0x00000208, 0x08020200, 0x00000000, 0x08020008,        0x08000200, 0x00000000, 0x00020208, 0x08000200,        0x00020008, 0x08000008, 0x08000008, 0x00020000,        0x08020208, 0x00020008, 0x08020000, 0x00000208,        0x08000000, 0x00000008, 0x08020200, 0x00000200,        0x00020200, 0x08020000, 0x08020008, 0x00020208,        0x08000208, 0x00020200, 0x00020000, 0x08000208,        0x00000008, 0x08020208, 0x00000200, 0x08000000,        0x08020200, 0x08000000, 0x00020008, 0x00000208,        0x00020000, 0x08020200, 0x08000200, 0x00000000,        0x00000200, 0x00020008, 0x08020208, 0x08000200,        0x08000008, 0x00000200, 0x00000000, 0x08020008,        0x08000208, 0x00020000, 0x08000000, 0x08020208,        0x00000008, 0x00020208, 0x00020200, 0x08000008,        0x08020000, 0x08000208, 0x00000208, 0x08020000,        0x00020208, 0x00000008, 0x08020008, 0x00020200    };    static int[] SP4 = {        0x00802001, 0x00002081, 0x00002081, 0x00000080,        0x00802080, 0x00800081, 0x00800001, 0x00002001,        0x00000000, 0x00802000, 0x00802000, 0x00802081,        0x00000081, 0x00000000, 0x00800080, 0x00800001,        0x00000001, 0x00002000, 0x00800000, 0x00802001,        0x00000080, 0x00800000, 0x00002001, 0x00002080,        0x00800081, 0x00000001, 0x00002080, 0x00800080,        0x00002000, 0x00802080, 0x00802081, 0x00000081,        0x00800080, 0x00800001, 0x00802000, 0x00802081,        0x00000081, 0x00000000, 0x00000000, 0x00802000,        0x00002080, 0x00800080, 0x00800081, 0x00000001,        0x00802001, 0x00002081, 0x00002081, 0x00000080,        0x00802081, 0x00000081, 0x00000001, 0x00002000,        0x00800001, 0x00002001, 0x00802080, 0x00800081,        0x00002001, 0x00002080, 0x00800000, 0x00802001,        0x00000080, 0x00800000, 0x00002000, 0x00802080    };    static int[] SP5 = {        0x00000100, 0x02080100, 0x02080000, 0x42000100,        0x00080000, 0x00000100, 0x40000000, 0x02080000,        0x40080100, 0x00080000, 0x02000100, 0x40080100,        0x42000100, 0x42080000, 0x00080100, 0x40000000,        0x02000000, 0x40080000, 0x40080000, 0x00000000,        0x40000100, 0x42080100, 0x42080100, 0x02000100,        0x42080000, 0x40000100, 0x00000000, 0x42000000,        0x02080100, 0x02000000, 0x42000000, 0x00080100,        0x00080000, 0x42000100, 0x00000100, 0x02000000,        0x40000000, 0x02080000, 0x42000100, 0x40080100,        0x02000100, 0x40000000, 0x42080000, 0x02080100,        0x40080100, 0x00000100, 0x02000000, 0x42080000,        0x42080100, 0x00080100, 0x42000000, 0x42080100,        0x02080000, 0x00000000, 0x40080000, 0x42000000,        0x00080100, 0x02000100, 0x40000100, 0x00080000,        0x00000000, 0x40080000, 0x02080100, 0x40000100    };    static int[] SP6 = {        0x20000010, 0x20400000, 0x00004000, 0x20404010,        0x20400000, 0x00000010, 0x20404010, 0x00400000,        0x20004000, 0x00404010, 0x00400000, 0x20000010,        0x00400010, 0x20004000, 0x20000000, 0x00004010,        0x00000000, 0x00400010, 0x20004010, 0x00004000,        0x00404000, 0x20004010, 0x00000010, 0x20400010,