Java tutorial
package org.bouncycastle.crypto.engines; import org.bouncycastle.util.Pack; /** * Serpent is a 128-bit 32-round block cipher with variable key lengths, * including 128, 192 and 256 bit keys conjectured to be at least as * secure as three-key triple-DES. * <p> * Serpent was designed by Ross Anderson, Eli Biham and Lars Knudsen as a * candidate algorithm for the NIST AES Quest. * <p> * For full details see <a href="http://www.cl.cam.ac.uk/~rja14/serpent.html">The Serpent home page</a> */ public final class SerpentEngine extends SerpentEngineBase { /** * Expand a user-supplied key material into a session key. * * @param key The user-key bytes (multiples of 4) to use. * @exception IllegalArgumentException */ protected int[] makeWorkingKey(byte[] key) throws IllegalArgumentException { // // pad key to 256 bits // int[] kPad = new int[16]; int off = 0; int length = 0; for (off = 0; (off + 4) < key.length; off += 4) { kPad[length++] = Pack.littleEndianToInt(key, off); } if (off % 4 == 0) { kPad[length++] = Pack.littleEndianToInt(key, off); if (length < 8) { kPad[length] = 1; } } else { throw new IllegalArgumentException("key must be a multiple of 4 bytes"); } // // expand the padded key up to 33 x 128 bits of key material // int amount = (ROUNDS + 1) * 4; int[] w = new int[amount]; // // compute w0 to w7 from w-8 to w-1 // for (int i = 8; i < 16; i++) { kPad[i] = rotateLeft(kPad[i - 8] ^ kPad[i - 5] ^ kPad[i - 3] ^ kPad[i - 1] ^ PHI ^ (i - 8), 11); } System.arraycopy(kPad, 8, w, 0, 8); // // compute w8 to w136 // for (int i = 8; i < amount; i++) { w[i] = rotateLeft(w[i - 8] ^ w[i - 5] ^ w[i - 3] ^ w[i - 1] ^ PHI ^ i, 11); } // // create the working keys by processing w with the Sbox and IP // sb3(w[0], w[1], w[2], w[3]); w[0] = X0; w[1] = X1; w[2] = X2; w[3] = X3; sb2(w[4], w[5], w[6], w[7]); w[4] = X0; w[5] = X1; w[6] = X2; w[7] = X3; sb1(w[8], w[9], w[10], w[11]); w[8] = X0; w[9] = X1; w[10] = X2; w[11] = X3; sb0(w[12], w[13], w[14], w[15]); w[12] = X0; w[13] = X1; w[14] = X2; w[15] = X3; sb7(w[16], w[17], w[18], w[19]); w[16] = X0; w[17] = X1; w[18] = X2; w[19] = X3; sb6(w[20], w[21], w[22], w[23]); w[20] = X0; w[21] = X1; w[22] = X2; w[23] = X3; sb5(w[24], w[25], w[26], w[27]); w[24] = X0; w[25] = X1; w[26] = X2; w[27] = X3; sb4(w[28], w[29], w[30], w[31]); w[28] = X0; w[29] = X1; w[30] = X2; w[31] = X3; sb3(w[32], w[33], w[34], w[35]); w[32] = X0; w[33] = X1; w[34] = X2; w[35] = X3; sb2(w[36], w[37], w[38], w[39]); w[36] = X0; w[37] = X1; w[38] = X2; w[39] = X3; sb1(w[40], w[41], w[42], w[43]); w[40] = X0; w[41] = X1; w[42] = X2; w[43] = X3; sb0(w[44], w[45], w[46], w[47]); w[44] = X0; w[45] = X1; w[46] = X2; w[47] = X3; sb7(w[48], w[49], w[50], w[51]); w[48] = X0; w[49] = X1; w[50] = X2; w[51] = X3; sb6(w[52], w[53], w[54], w[55]); w[52] = X0; w[53] = X1; w[54] = X2; w[55] = X3; sb5(w[56], w[57], w[58], w[59]); w[56] = X0; w[57] = X1; w[58] = X2; w[59] = X3; sb4(w[60], w[61], w[62], w[63]); w[60] = X0; w[61] = X1; w[62] = X2; w[63] = X3; sb3(w[64], w[65], w[66], w[67]); w[64] = X0; w[65] = X1; w[66] = X2; w[67] = X3; sb2(w[68], w[69], w[70], w[71]); w[68] = X0; w[69] = X1; w[70] = X2; w[71] = X3; sb1(w[72], w[73], w[74], w[75]); w[72] = X0; w[73] = X1; w[74] = X2; w[75] = X3; sb0(w[76], w[77], w[78], w[79]); w[76] = X0; w[77] = X1; w[78] = X2; w[79] = X3; sb7(w[80], w[81], w[82], w[83]); w[80] = X0; w[81] = X1; w[82] = X2; w[83] = X3; sb6(w[84], w[85], w[86], w[87]); w[84] = X0; w[85] = X1; w[86] = X2; w[87] = X3; sb5(w[88], w[89], w[90], w[91]); w[88] = X0; w[89] = X1; w[90] = X2; w[91] = X3; sb4(w[92], w[93], w[94], w[95]); w[92] = X0; w[93] = X1; w[94] = X2; w[95] = X3; sb3(w[96], w[97], w[98], w[99]); w[96] = X0; w[97] = X1; w[98] = X2; w[99] = X3; sb2(w[100], w[101], w[102], w[103]); w[100] = X0; w[101] = X1; w[102] = X2; w[103] = X3; sb1(w[104], w[105], w[106], w[107]); w[104] = X0; w[105] = X1; w[106] = X2; w[107] = X3; sb0(w[108], w[109], w[110], w[111]); w[108] = X0; w[109] = X1; w[110] = X2; w[111] = X3; sb7(w[112], w[113], w[114], w[115]); w[112] = X0; w[113] = X1; w[114] = X2; w[115] = X3; sb6(w[116], w[117], w[118], w[119]); w[116] = X0; w[117] = X1; w[118] = X2; w[119] = X3; sb5(w[120], w[121], w[122], w[123]); w[120] = X0; w[121] = X1; w[122] = X2; w[123] = X3; sb4(w[124], w[125], w[126], w[127]); w[124] = X0; w[125] = X1; w[126] = X2; w[127] = X3; sb3(w[128], w[129], w[130], w[131]); w[128] = X0; w[129] = X1; w[130] = X2; w[131] = X3; return w; } /** * Encrypt one block of plaintext. * * @param input the array containing the input data. * @param inOff offset into the in array the data starts at. * @param output the array the output data will be copied into. * @param outOff the offset into the out array the output will start at. */ protected void encryptBlock(byte[] input, int inOff, byte[] output, int outOff) { X0 = Pack.littleEndianToInt(input, inOff); X1 = Pack.littleEndianToInt(input, inOff + 4); X2 = Pack.littleEndianToInt(input, inOff + 8); X3 = Pack.littleEndianToInt(input, inOff + 12); sb0(wKey[0] ^ X0, wKey[1] ^ X1, wKey[2] ^ X2, wKey[3] ^ X3); LT(); sb1(wKey[4] ^ X0, wKey[5] ^ X1, wKey[6] ^ X2, wKey[7] ^ X3); LT(); sb2(wKey[8] ^ X0, wKey[9] ^ X1, wKey[10] ^ X2, wKey[11] ^ X3); LT(); sb3(wKey[12] ^ X0, wKey[13] ^ X1, wKey[14] ^ X2, wKey[15] ^ X3); LT(); sb4(wKey[16] ^ X0, wKey[17] ^ X1, wKey[18] ^ X2, wKey[19] ^ X3); LT(); sb5(wKey[20] ^ X0, wKey[21] ^ X1, wKey[22] ^ X2, wKey[23] ^ X3); LT(); sb6(wKey[24] ^ X0, wKey[25] ^ X1, wKey[26] ^ X2, wKey[27] ^ X3); LT(); sb7(wKey[28] ^ X0, wKey[29] ^ X1, wKey[30] ^ X2, wKey[31] ^ X3); LT(); sb0(wKey[32] ^ X0, wKey[33] ^ X1, wKey[34] ^ X2, wKey[35] ^ X3); LT(); sb1(wKey[36] ^ X0, wKey[37] ^ X1, wKey[38] ^ X2, wKey[39] ^ X3); LT(); sb2(wKey[40] ^ X0, wKey[41] ^ X1, wKey[42] ^ X2, wKey[43] ^ X3); LT(); sb3(wKey[44] ^ X0, wKey[45] ^ X1, wKey[46] ^ X2, wKey[47] ^ X3); LT(); sb4(wKey[48] ^ X0, wKey[49] ^ X1, wKey[50] ^ X2, wKey[51] ^ X3); LT(); sb5(wKey[52] ^ X0, wKey[53] ^ X1, wKey[54] ^ X2, wKey[55] ^ X3); LT(); sb6(wKey[56] ^ X0, wKey[57] ^ X1, wKey[58] ^ X2, wKey[59] ^ X3); LT(); sb7(wKey[60] ^ X0, wKey[61] ^ X1, wKey[62] ^ X2, wKey[63] ^ X3); LT(); sb0(wKey[64] ^ X0, wKey[65] ^ X1, wKey[66] ^ X2, wKey[67] ^ X3); LT(); sb1(wKey[68] ^ X0, wKey[69] ^ X1, wKey[70] ^ X2, wKey[71] ^ X3); LT(); sb2(wKey[72] ^ X0, wKey[73] ^ X1, wKey[74] ^ X2, wKey[75] ^ X3); LT(); sb3(wKey[76] ^ X0, wKey[77] ^ X1, wKey[78] ^ X2, wKey[79] ^ X3); LT(); sb4(wKey[80] ^ X0, wKey[81] ^ X1, wKey[82] ^ X2, wKey[83] ^ X3); LT(); sb5(wKey[84] ^ X0, wKey[85] ^ X1, wKey[86] ^ X2, wKey[87] ^ X3); LT(); sb6(wKey[88] ^ X0, wKey[89] ^ X1, wKey[90] ^ X2, wKey[91] ^ X3); LT(); sb7(wKey[92] ^ X0, wKey[93] ^ X1, wKey[94] ^ X2, wKey[95] ^ X3); LT(); sb0(wKey[96] ^ X0, wKey[97] ^ X1, wKey[98] ^ X2, wKey[99] ^ X3); LT(); sb1(wKey[100] ^ X0, wKey[101] ^ X1, wKey[102] ^ X2, wKey[103] ^ X3); LT(); sb2(wKey[104] ^ X0, wKey[105] ^ X1, wKey[106] ^ X2, wKey[107] ^ X3); LT(); sb3(wKey[108] ^ X0, wKey[109] ^ X1, wKey[110] ^ X2, wKey[111] ^ X3); LT(); sb4(wKey[112] ^ X0, wKey[113] ^ X1, wKey[114] ^ X2, wKey[115] ^ X3); LT(); sb5(wKey[116] ^ X0, wKey[117] ^ X1, wKey[118] ^ X2, wKey[119] ^ X3); LT(); sb6(wKey[120] ^ X0, wKey[121] ^ X1, wKey[122] ^ X2, wKey[123] ^ X3); LT(); sb7(wKey[124] ^ X0, wKey[125] ^ X1, wKey[126] ^ X2, wKey[127] ^ X3); Pack.intToLittleEndian(wKey[128] ^ X0, output, outOff); Pack.intToLittleEndian(wKey[129] ^ X1, output, outOff + 4); Pack.intToLittleEndian(wKey[130] ^ X2, output, outOff + 8); Pack.intToLittleEndian(wKey[131] ^ X3, output, outOff + 12); } /** * Decrypt one block of ciphertext. * * @param input the array containing the input data. * @param inOff offset into the in array the data starts at. * @param output the array the output data will be copied into. * @param outOff the offset into the out array the output will start at. */ protected void decryptBlock(byte[] input, int inOff, byte[] output, int outOff) { X0 = wKey[128] ^ Pack.littleEndianToInt(input, inOff); X1 = wKey[129] ^ Pack.littleEndianToInt(input, inOff + 4); X2 = wKey[130] ^ Pack.littleEndianToInt(input, inOff + 8); X3 = wKey[131] ^ Pack.littleEndianToInt(input, inOff + 12); ib7(X0, X1, X2, X3); X0 ^= wKey[124]; X1 ^= wKey[125]; X2 ^= wKey[126]; X3 ^= wKey[127]; inverseLT(); ib6(X0, X1, X2, X3); X0 ^= wKey[120]; X1 ^= wKey[121]; X2 ^= wKey[122]; X3 ^= wKey[123]; inverseLT(); ib5(X0, X1, X2, X3); X0 ^= wKey[116]; X1 ^= wKey[117]; X2 ^= wKey[118]; X3 ^= wKey[119]; inverseLT(); ib4(X0, X1, X2, X3); X0 ^= wKey[112]; X1 ^= wKey[113]; X2 ^= wKey[114]; X3 ^= wKey[115]; inverseLT(); ib3(X0, X1, X2, X3); X0 ^= wKey[108]; X1 ^= wKey[109]; X2 ^= wKey[110]; X3 ^= wKey[111]; inverseLT(); ib2(X0, X1, X2, X3); X0 ^= wKey[104]; X1 ^= wKey[105]; X2 ^= wKey[106]; X3 ^= wKey[107]; inverseLT(); ib1(X0, X1, X2, X3); X0 ^= wKey[100]; X1 ^= wKey[101]; X2 ^= wKey[102]; X3 ^= wKey[103]; inverseLT(); ib0(X0, X1, X2, X3); X0 ^= wKey[96]; X1 ^= wKey[97]; X2 ^= wKey[98]; X3 ^= wKey[99]; inverseLT(); ib7(X0, X1, X2, X3); X0 ^= wKey[92]; X1 ^= wKey[93]; X2 ^= wKey[94]; X3 ^= wKey[95]; inverseLT(); ib6(X0, X1, X2, X3); X0 ^= wKey[88]; X1 ^= wKey[89]; X2 ^= wKey[90]; X3 ^= wKey[91]; inverseLT(); ib5(X0, X1, X2, X3); X0 ^= wKey[84]; X1 ^= wKey[85]; X2 ^= wKey[86]; X3 ^= wKey[87]; inverseLT(); ib4(X0, X1, X2, X3); X0 ^= wKey[80]; X1 ^= wKey[81]; X2 ^= wKey[82]; X3 ^= wKey[83]; inverseLT(); ib3(X0, X1, X2, X3); X0 ^= wKey[76]; X1 ^= wKey[77]; X2 ^= wKey[78]; X3 ^= wKey[79]; inverseLT(); ib2(X0, X1, X2, X3); X0 ^= wKey[72]; X1 ^= wKey[73]; X2 ^= wKey[74]; X3 ^= wKey[75]; inverseLT(); ib1(X0, X1, X2, X3); X0 ^= wKey[68]; X1 ^= wKey[69]; X2 ^= wKey[70]; X3 ^= wKey[71]; inverseLT(); ib0(X0, X1, X2, X3); X0 ^= wKey[64]; X1 ^= wKey[65]; X2 ^= wKey[66]; X3 ^= wKey[67]; inverseLT(); ib7(X0, X1, X2, X3); X0 ^= wKey[60]; X1 ^= wKey[61]; X2 ^= wKey[62]; X3 ^= wKey[63]; inverseLT(); ib6(X0, X1, X2, X3); X0 ^= wKey[56]; X1 ^= wKey[57]; X2 ^= wKey[58]; X3 ^= wKey[59]; inverseLT(); ib5(X0, X1, X2, X3); X0 ^= wKey[52]; X1 ^= wKey[53]; X2 ^= wKey[54]; X3 ^= wKey[55]; inverseLT(); ib4(X0, X1, X2, X3); X0 ^= wKey[48]; X1 ^= wKey[49]; X2 ^= wKey[50]; X3 ^= wKey[51]; inverseLT(); ib3(X0, X1, X2, X3); X0 ^= wKey[44]; X1 ^= wKey[45]; X2 ^= wKey[46]; X3 ^= wKey[47]; inverseLT(); ib2(X0, X1, X2, X3); X0 ^= wKey[40]; X1 ^= wKey[41]; X2 ^= wKey[42]; X3 ^= wKey[43]; inverseLT(); ib1(X0, X1, X2, X3); X0 ^= wKey[36]; X1 ^= wKey[37]; X2 ^= wKey[38]; X3 ^= wKey[39]; inverseLT(); ib0(X0, X1, X2, X3); X0 ^= wKey[32]; X1 ^= wKey[33]; X2 ^= wKey[34]; X3 ^= wKey[35]; inverseLT(); ib7(X0, X1, X2, X3); X0 ^= wKey[28]; X1 ^= wKey[29]; X2 ^= wKey[30]; X3 ^= wKey[31]; inverseLT(); ib6(X0, X1, X2, X3); X0 ^= wKey[24]; X1 ^= wKey[25]; X2 ^= wKey[26]; X3 ^= wKey[27]; inverseLT(); ib5(X0, X1, X2, X3); X0 ^= wKey[20]; X1 ^= wKey[21]; X2 ^= wKey[22]; X3 ^= wKey[23]; inverseLT(); ib4(X0, X1, X2, X3); X0 ^= wKey[16]; X1 ^= wKey[17]; X2 ^= wKey[18]; X3 ^= wKey[19]; inverseLT(); ib3(X0, X1, X2, X3); X0 ^= wKey[12]; X1 ^= wKey[13]; X2 ^= wKey[14]; X3 ^= wKey[15]; inverseLT(); ib2(X0, X1, X2, X3); X0 ^= wKey[8]; X1 ^= wKey[9]; X2 ^= wKey[10]; X3 ^= wKey[11]; inverseLT(); ib1(X0, X1, X2, X3); X0 ^= wKey[4]; X1 ^= wKey[5]; X2 ^= wKey[6]; X3 ^= wKey[7]; inverseLT(); ib0(X0, X1, X2, X3); Pack.intToLittleEndian(X0 ^ wKey[0], output, outOff); Pack.intToLittleEndian(X1 ^ wKey[1], output, outOff + 4); Pack.intToLittleEndian(X2 ^ wKey[2], output, outOff + 8); Pack.intToLittleEndian(X3 ^ wKey[3], output, outOff + 12); } }