Java tutorial
package org.bouncycastle.crypto.engines; import org.bouncycastle.crypto.BlockCipher; import org.bouncycastle.crypto.CipherParameters; import org.bouncycastle.crypto.DataLengthException; import org.bouncycastle.crypto.OutputLengthException; import org.bouncycastle.crypto.params.KeyParameter; import org.bouncycastle.util.Pack; /** * 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 OutputLengthException("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... */ // private static final 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 // }; private static final short[] bytebit = { 0200, 0100, 040, 020, 010, 04, 02, 01 }; private static final 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). */ private static final 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 }; private static final byte[] totrot = { 1, 2, 4, 6, 8, 10, 12, 14, 15, 17, 19, 21, 23, 25, 27, 28 }; private static final 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 }; private static final 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 }; private static final 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 }; private static final 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 }; private static final 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 }; private static final 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 }; private static final 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, 0x20400010, 0x00000000, 0x00404010, 0x20404000, 0x00004010, 0x00404000, 0x20404000, 0x20000000, 0x20004000, 0x00000010, 0x20400010, 0x00404000, 0x20404010, 0x00400000, 0x00004010, 0x20000010, 0x00400000, 0x20004000, 0x20000000, 0x00004010, 0x20000010, 0x20404010, 0x00404000, 0x20400000, 0x00404010, 0x20404000, 0x00000000, 0x20400010, 0x00000010, 0x00004000, 0x20400000, 0x00404010, 0x00004000, 0x00400010, 0x20004010, 0x00000000, 0x20404000, 0x20000000, 0x00400010, 0x20004010 }; private static final int[] SP7 = { 0x00200000, 0x04200002, 0x04000802, 0x00000000, 0x00000800, 0x04000802, 0x00200802, 0x04200800, 0x04200802, 0x00200000, 0x00000000, 0x04000002, 0x00000002, 0x04000000, 0x04200002, 0x00000802, 0x04000800, 0x00200802, 0x00200002, 0x04000800, 0x04000002, 0x04200000, 0x04200800, 0x00200002, 0x04200000, 0x00000800, 0x00000802, 0x04200802, 0x00200800, 0x00000002, 0x04000000, 0x00200800, 0x04000000, 0x00200800, 0x00200000, 0x04000802, 0x04000802, 0x04200002, 0x04200002, 0x00000002, 0x00200002, 0x04000000, 0x04000800, 0x00200000, 0x04200800, 0x00000802, 0x00200802, 0x04200800, 0x00000802, 0x04000002, 0x04200802, 0x04200000, 0x00200800, 0x00000000, 0x00000002, 0x04200802, 0x00000000, 0x00200802, 0x04200000, 0x00000800, 0x04000002, 0x04000800, 0x00000800, 0x00200002 }; private static final int[] SP8 = { 0x10001040, 0x00001000, 0x00040000, 0x10041040, 0x10000000, 0x10001040, 0x00000040, 0x10000000, 0x00040040, 0x10040000, 0x10041040, 0x00041000, 0x10041000, 0x00041040, 0x00001000, 0x00000040, 0x10040000, 0x10000040, 0x10001000, 0x00001040, 0x00041000, 0x00040040, 0x10040040, 0x10041000, 0x00001040, 0x00000000, 0x00000000, 0x10040040, 0x10000040, 0x10001000, 0x00041040, 0x00040000, 0x00041040, 0x00040000, 0x10041000, 0x00001000, 0x00000040, 0x10040040, 0x00001000, 0x00041040, 0x10001000, 0x00000040, 0x10000040, 0x10040000, 0x10040040, 0x10000000, 0x00040000, 0x10001040, 0x00000000, 0x10041040, 0x00040040, 0x10000040, 0x10040000, 0x10001000, 0x10001040, 0x00000000, 0x10041040, 0x00041000, 0x00041000, 0x00001040, 0x00001040, 0x00040040, 0x10000000, 0x10041000 }; /** * generate an integer based working key based on our secret key * and what we processing we are planning to do. * * Acknowledgements for this routine go to James Gillogly & Phil Karn. * (whoever, and wherever they are!). */ protected int[] generateWorkingKey(boolean encrypting, byte[] key) { int[] newKey = new int[32]; boolean[] pc1m = new boolean[56], pcr = new boolean[56]; for (int j = 0; j < 56; j++) { int l = pc1[j]; pc1m[j] = ((key[l >>> 3] & bytebit[l & 07]) != 0); } for (int i = 0; i < 16; i++) { int l, m, n; if (encrypting) { m = i << 1; } else { m = (15 - i) << 1; } n = m + 1; newKey[m] = newKey[n] = 0; for (int j = 0; j < 28; j++) { l = j + totrot[i]; if (l < 28) { pcr[j] = pc1m[l]; } else { pcr[j] = pc1m[l - 28]; } } for (int j = 28; j < 56; j++) { l = j + totrot[i]; if (l < 56) { pcr[j] = pc1m[l]; } else { pcr[j] = pc1m[l - 28]; } } for (int j = 0; j < 24; j++) { if (pcr[pc2[j]]) { newKey[m] |= bigbyte[j]; } if (pcr[pc2[j + 24]]) { newKey[n] |= bigbyte[j]; } } } // // store the processed key // for (int i = 0; i != 32; i += 2) { int i1, i2; i1 = newKey[i]; i2 = newKey[i + 1]; newKey[i] = ((i1 & 0x00fc0000) << 6) | ((i1 & 0x00000fc0) << 10) | ((i2 & 0x00fc0000) >>> 10) | ((i2 & 0x00000fc0) >>> 6); newKey[i + 1] = ((i1 & 0x0003f000) << 12) | ((i1 & 0x0000003f) << 16) | ((i2 & 0x0003f000) >>> 4) | (i2 & 0x0000003f); } return newKey; } /** * the DES engine. */ protected void desFunc(int[] wKey, byte[] in, int inOff, byte[] out, int outOff) { int work, right, left; left = Pack.bigEndianToInt(in, inOff); right = Pack.bigEndianToInt(in, inOff + 4); work = ((left >>> 4) ^ right) & 0x0f0f0f0f; right ^= work; left ^= (work << 4); work = ((left >>> 16) ^ right) & 0x0000ffff; right ^= work; left ^= (work << 16); work = ((right >>> 2) ^ left) & 0x33333333; left ^= work; right ^= (work << 2); work = ((right >>> 8) ^ left) & 0x00ff00ff; left ^= work; right ^= (work << 8); right = (right << 1) | (right >>> 31); work = (left ^ right) & 0xaaaaaaaa; left ^= work; right ^= work; left = (left << 1) | (left >>> 31); for (int round = 0; round < 8; round++) { int fval; work = (right << 28) | (right >>> 4); work ^= wKey[round * 4 + 0]; fval = SP7[work & 0x3f]; fval |= SP5[(work >>> 8) & 0x3f]; fval |= SP3[(work >>> 16) & 0x3f]; fval |= SP1[(work >>> 24) & 0x3f]; work = right ^ wKey[round * 4 + 1]; fval |= SP8[work & 0x3f]; fval |= SP6[(work >>> 8) & 0x3f]; fval |= SP4[(work >>> 16) & 0x3f]; fval |= SP2[(work >>> 24) & 0x3f]; left ^= fval; work = (left << 28) | (left >>> 4); work ^= wKey[round * 4 + 2]; fval = SP7[work & 0x3f]; fval |= SP5[(work >>> 8) & 0x3f]; fval |= SP3[(work >>> 16) & 0x3f]; fval |= SP1[(work >>> 24) & 0x3f]; work = left ^ wKey[round * 4 + 3]; fval |= SP8[work & 0x3f]; fval |= SP6[(work >>> 8) & 0x3f]; fval |= SP4[(work >>> 16) & 0x3f]; fval |= SP2[(work >>> 24) & 0x3f]; right ^= fval; } right = (right << 31) | (right >>> 1); work = (left ^ right) & 0xaaaaaaaa; left ^= work; right ^= work; left = (left << 31) | (left >>> 1); work = ((left >>> 8) ^ right) & 0x00ff00ff; right ^= work; left ^= (work << 8); work = ((left >>> 2) ^ right) & 0x33333333; right ^= work; left ^= (work << 2); work = ((right >>> 16) ^ left) & 0x0000ffff; left ^= work; right ^= (work << 16); work = ((right >>> 4) ^ left) & 0x0f0f0f0f; left ^= work; right ^= (work << 4); Pack.intToBigEndian(right, out, outOff); Pack.intToBigEndian(left, out, outOff + 4); } }