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Diffstat (limited to 'Crypto/src/crypto/engines/AesEngine.cs')
| -rw-r--r-- | Crypto/src/crypto/engines/AesEngine.cs | 525 |
1 files changed, 525 insertions, 0 deletions
diff --git a/Crypto/src/crypto/engines/AesEngine.cs b/Crypto/src/crypto/engines/AesEngine.cs new file mode 100644 index 000000000..4211a9559 --- /dev/null +++ b/Crypto/src/crypto/engines/AesEngine.cs @@ -0,0 +1,525 @@ +using System; + +using Org.BouncyCastle.Crypto.Parameters; +using Org.BouncyCastle.Crypto.Utilities; + +namespace Org.BouncyCastle.Crypto.Engines +{ + /** + * an implementation of the AES (Rijndael), from FIPS-197. + * <p> + * For further details see: <a href="http://csrc.nist.gov/encryption/aes/">http://csrc.nist.gov/encryption/aes/</a>. + * + * This implementation is based on optimizations from Dr. Brian Gladman's paper and C code at + * <a href="http://fp.gladman.plus.com/cryptography_technology/rijndael/">http://fp.gladman.plus.com/cryptography_technology/rijndael/</a> + * + * There are three levels of tradeoff of speed vs memory + * Because java has no preprocessor, they are written as three separate classes from which to choose + * + * The fastest uses 8Kbytes of static tables to precompute round calculations, 4 256 word tables for encryption + * and 4 for decryption. + * + * The middle performance version uses only one 256 word table for each, for a total of 2Kbytes, + * adding 12 rotate operations per round to compute the values contained in the other tables from + * the contents of the first. + * + * The slowest version uses no static tables at all and computes the values in each round. + * </p> + * <p> + * This file contains the middle performance version with 2Kbytes of static tables for round precomputation. + * </p> + */ + public class AesEngine + : IBlockCipher + { + // The S box + private static readonly byte[] S = + { + 99, 124, 119, 123, 242, 107, 111, 197, + 48, 1, 103, 43, 254, 215, 171, 118, + 202, 130, 201, 125, 250, 89, 71, 240, + 173, 212, 162, 175, 156, 164, 114, 192, + 183, 253, 147, 38, 54, 63, 247, 204, + 52, 165, 229, 241, 113, 216, 49, 21, + 4, 199, 35, 195, 24, 150, 5, 154, + 7, 18, 128, 226, 235, 39, 178, 117, + 9, 131, 44, 26, 27, 110, 90, 160, + 82, 59, 214, 179, 41, 227, 47, 132, + 83, 209, 0, 237, 32, 252, 177, 91, + 106, 203, 190, 57, 74, 76, 88, 207, + 208, 239, 170, 251, 67, 77, 51, 133, + 69, 249, 2, 127, 80, 60, 159, 168, + 81, 163, 64, 143, 146, 157, 56, 245, + 188, 182, 218, 33, 16, 255, 243, 210, + 205, 12, 19, 236, 95, 151, 68, 23, + 196, 167, 126, 61, 100, 93, 25, 115, + 96, 129, 79, 220, 34, 42, 144, 136, + 70, 238, 184, 20, 222, 94, 11, 219, + 224, 50, 58, 10, 73, 6, 36, 92, + 194, 211, 172, 98, 145, 149, 228, 121, + 231, 200, 55, 109, 141, 213, 78, 169, + 108, 86, 244, 234, 101, 122, 174, 8, + 186, 120, 37, 46, 28, 166, 180, 198, + 232, 221, 116, 31, 75, 189, 139, 138, + 112, 62, 181, 102, 72, 3, 246, 14, + 97, 53, 87, 185, 134, 193, 29, 158, + 225, 248, 152, 17, 105, 217, 142, 148, + 155, 30, 135, 233, 206, 85, 40, 223, + 140, 161, 137, 13, 191, 230, 66, 104, + 65, 153, 45, 15, 176, 84, 187, 22, + }; + + // The inverse S-box + private static readonly byte[] Si = + { + 82, 9, 106, 213, 48, 54, 165, 56, + 191, 64, 163, 158, 129, 243, 215, 251, + 124, 227, 57, 130, 155, 47, 255, 135, + 52, 142, 67, 68, 196, 222, 233, 203, + 84, 123, 148, 50, 166, 194, 35, 61, + 238, 76, 149, 11, 66, 250, 195, 78, + 8, 46, 161, 102, 40, 217, 36, 178, + 118, 91, 162, 73, 109, 139, 209, 37, + 114, 248, 246, 100, 134, 104, 152, 22, + 212, 164, 92, 204, 93, 101, 182, 146, + 108, 112, 72, 80, 253, 237, 185, 218, + 94, 21, 70, 87, 167, 141, 157, 132, + 144, 216, 171, 0, 140, 188, 211, 10, + 247, 228, 88, 5, 184, 179, 69, 6, + 208, 44, 30, 143, 202, 63, 15, 2, + 193, 175, 189, 3, 1, 19, 138, 107, + 58, 145, 17, 65, 79, 103, 220, 234, + 151, 242, 207, 206, 240, 180, 230, 115, + 150, 172, 116, 34, 231, 173, 53, 133, + 226, 249, 55, 232, 28, 117, 223, 110, + 71, 241, 26, 113, 29, 41, 197, 137, + 111, 183, 98, 14, 170, 24, 190, 27, + 252, 86, 62, 75, 198, 210, 121, 32, + 154, 219, 192, 254, 120, 205, 90, 244, + 31, 221, 168, 51, 136, 7, 199, 49, + 177, 18, 16, 89, 39, 128, 236, 95, + 96, 81, 127, 169, 25, 181, 74, 13, + 45, 229, 122, 159, 147, 201, 156, 239, + 160, 224, 59, 77, 174, 42, 245, 176, + 200, 235, 187, 60, 131, 83, 153, 97, + 23, 43, 4, 126, 186, 119, 214, 38, + 225, 105, 20, 99, 85, 33, 12, 125, + }; + + // vector used in calculating key schedule (powers of x in GF(256)) + private static readonly byte[] rcon = + { + 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, + 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91 + }; + + // precomputation tables of calculations for rounds + private static readonly uint[] T0 = + { + 0xa56363c6, 0x847c7cf8, 0x997777ee, 0x8d7b7bf6, 0x0df2f2ff, + 0xbd6b6bd6, 0xb16f6fde, 0x54c5c591, 0x50303060, 0x03010102, + 0xa96767ce, 0x7d2b2b56, 0x19fefee7, 0x62d7d7b5, 0xe6abab4d, + 0x9a7676ec, 0x45caca8f, 0x9d82821f, 0x40c9c989, 0x877d7dfa, + 0x15fafaef, 0xeb5959b2, 0xc947478e, 0x0bf0f0fb, 0xecadad41, + 0x67d4d4b3, 0xfda2a25f, 0xeaafaf45, 0xbf9c9c23, 0xf7a4a453, + 0x967272e4, 0x5bc0c09b, 0xc2b7b775, 0x1cfdfde1, 0xae93933d, + 0x6a26264c, 0x5a36366c, 0x413f3f7e, 0x02f7f7f5, 0x4fcccc83, + 0x5c343468, 0xf4a5a551, 0x34e5e5d1, 0x08f1f1f9, 0x937171e2, + 0x73d8d8ab, 0x53313162, 0x3f15152a, 0x0c040408, 0x52c7c795, + 0x65232346, 0x5ec3c39d, 0x28181830, 0xa1969637, 0x0f05050a, + 0xb59a9a2f, 0x0907070e, 0x36121224, 0x9b80801b, 0x3de2e2df, + 0x26ebebcd, 0x6927274e, 0xcdb2b27f, 0x9f7575ea, 0x1b090912, + 0x9e83831d, 0x742c2c58, 0x2e1a1a34, 0x2d1b1b36, 0xb26e6edc, + 0xee5a5ab4, 0xfba0a05b, 0xf65252a4, 0x4d3b3b76, 0x61d6d6b7, + 0xceb3b37d, 0x7b292952, 0x3ee3e3dd, 0x712f2f5e, 0x97848413, + 0xf55353a6, 0x68d1d1b9, 0x00000000, 0x2cededc1, 0x60202040, + 0x1ffcfce3, 0xc8b1b179, 0xed5b5bb6, 0xbe6a6ad4, 0x46cbcb8d, + 0xd9bebe67, 0x4b393972, 0xde4a4a94, 0xd44c4c98, 0xe85858b0, + 0x4acfcf85, 0x6bd0d0bb, 0x2aefefc5, 0xe5aaaa4f, 0x16fbfbed, + 0xc5434386, 0xd74d4d9a, 0x55333366, 0x94858511, 0xcf45458a, + 0x10f9f9e9, 0x06020204, 0x817f7ffe, 0xf05050a0, 0x443c3c78, + 0xba9f9f25, 0xe3a8a84b, 0xf35151a2, 0xfea3a35d, 0xc0404080, + 0x8a8f8f05, 0xad92923f, 0xbc9d9d21, 0x48383870, 0x04f5f5f1, + 0xdfbcbc63, 0xc1b6b677, 0x75dadaaf, 0x63212142, 0x30101020, + 0x1affffe5, 0x0ef3f3fd, 0x6dd2d2bf, 0x4ccdcd81, 0x140c0c18, + 0x35131326, 0x2fececc3, 0xe15f5fbe, 0xa2979735, 0xcc444488, + 0x3917172e, 0x57c4c493, 0xf2a7a755, 0x827e7efc, 0x473d3d7a, + 0xac6464c8, 0xe75d5dba, 0x2b191932, 0x957373e6, 0xa06060c0, + 0x98818119, 0xd14f4f9e, 0x7fdcdca3, 0x66222244, 0x7e2a2a54, + 0xab90903b, 0x8388880b, 0xca46468c, 0x29eeeec7, 0xd3b8b86b, + 0x3c141428, 0x79dedea7, 0xe25e5ebc, 0x1d0b0b16, 0x76dbdbad, + 0x3be0e0db, 0x56323264, 0x4e3a3a74, 0x1e0a0a14, 0xdb494992, + 0x0a06060c, 0x6c242448, 0xe45c5cb8, 0x5dc2c29f, 0x6ed3d3bd, + 0xefacac43, 0xa66262c4, 0xa8919139, 0xa4959531, 0x37e4e4d3, + 0x8b7979f2, 0x32e7e7d5, 0x43c8c88b, 0x5937376e, 0xb76d6dda, + 0x8c8d8d01, 0x64d5d5b1, 0xd24e4e9c, 0xe0a9a949, 0xb46c6cd8, + 0xfa5656ac, 0x07f4f4f3, 0x25eaeacf, 0xaf6565ca, 0x8e7a7af4, + 0xe9aeae47, 0x18080810, 0xd5baba6f, 0x887878f0, 0x6f25254a, + 0x722e2e5c, 0x241c1c38, 0xf1a6a657, 0xc7b4b473, 0x51c6c697, + 0x23e8e8cb, 0x7cdddda1, 0x9c7474e8, 0x211f1f3e, 0xdd4b4b96, + 0xdcbdbd61, 0x868b8b0d, 0x858a8a0f, 0x907070e0, 0x423e3e7c, + 0xc4b5b571, 0xaa6666cc, 0xd8484890, 0x05030306, 0x01f6f6f7, + 0x120e0e1c, 0xa36161c2, 0x5f35356a, 0xf95757ae, 0xd0b9b969, + 0x91868617, 0x58c1c199, 0x271d1d3a, 0xb99e9e27, 0x38e1e1d9, + 0x13f8f8eb, 0xb398982b, 0x33111122, 0xbb6969d2, 0x70d9d9a9, + 0x898e8e07, 0xa7949433, 0xb69b9b2d, 0x221e1e3c, 0x92878715, + 0x20e9e9c9, 0x49cece87, 0xff5555aa, 0x78282850, 0x7adfdfa5, + 0x8f8c8c03, 0xf8a1a159, 0x80898909, 0x170d0d1a, 0xdabfbf65, + 0x31e6e6d7, 0xc6424284, 0xb86868d0, 0xc3414182, 0xb0999929, + 0x772d2d5a, 0x110f0f1e, 0xcbb0b07b, 0xfc5454a8, 0xd6bbbb6d, + 0x3a16162c + }; + + private static readonly uint[] Tinv0 = + { + 0x50a7f451, 0x5365417e, 0xc3a4171a, 0x965e273a, 0xcb6bab3b, + 0xf1459d1f, 0xab58faac, 0x9303e34b, 0x55fa3020, 0xf66d76ad, + 0x9176cc88, 0x254c02f5, 0xfcd7e54f, 0xd7cb2ac5, 0x80443526, + 0x8fa362b5, 0x495ab1de, 0x671bba25, 0x980eea45, 0xe1c0fe5d, + 0x02752fc3, 0x12f04c81, 0xa397468d, 0xc6f9d36b, 0xe75f8f03, + 0x959c9215, 0xeb7a6dbf, 0xda595295, 0x2d83bed4, 0xd3217458, + 0x2969e049, 0x44c8c98e, 0x6a89c275, 0x78798ef4, 0x6b3e5899, + 0xdd71b927, 0xb64fe1be, 0x17ad88f0, 0x66ac20c9, 0xb43ace7d, + 0x184adf63, 0x82311ae5, 0x60335197, 0x457f5362, 0xe07764b1, + 0x84ae6bbb, 0x1ca081fe, 0x942b08f9, 0x58684870, 0x19fd458f, + 0x876cde94, 0xb7f87b52, 0x23d373ab, 0xe2024b72, 0x578f1fe3, + 0x2aab5566, 0x0728ebb2, 0x03c2b52f, 0x9a7bc586, 0xa50837d3, + 0xf2872830, 0xb2a5bf23, 0xba6a0302, 0x5c8216ed, 0x2b1ccf8a, + 0x92b479a7, 0xf0f207f3, 0xa1e2694e, 0xcdf4da65, 0xd5be0506, + 0x1f6234d1, 0x8afea6c4, 0x9d532e34, 0xa055f3a2, 0x32e18a05, + 0x75ebf6a4, 0x39ec830b, 0xaaef6040, 0x069f715e, 0x51106ebd, + 0xf98a213e, 0x3d06dd96, 0xae053edd, 0x46bde64d, 0xb58d5491, + 0x055dc471, 0x6fd40604, 0xff155060, 0x24fb9819, 0x97e9bdd6, + 0xcc434089, 0x779ed967, 0xbd42e8b0, 0x888b8907, 0x385b19e7, + 0xdbeec879, 0x470a7ca1, 0xe90f427c, 0xc91e84f8, 0x00000000, + 0x83868009, 0x48ed2b32, 0xac70111e, 0x4e725a6c, 0xfbff0efd, + 0x5638850f, 0x1ed5ae3d, 0x27392d36, 0x64d90f0a, 0x21a65c68, + 0xd1545b9b, 0x3a2e3624, 0xb1670a0c, 0x0fe75793, 0xd296eeb4, + 0x9e919b1b, 0x4fc5c080, 0xa220dc61, 0x694b775a, 0x161a121c, + 0x0aba93e2, 0xe52aa0c0, 0x43e0223c, 0x1d171b12, 0x0b0d090e, + 0xadc78bf2, 0xb9a8b62d, 0xc8a91e14, 0x8519f157, 0x4c0775af, + 0xbbdd99ee, 0xfd607fa3, 0x9f2601f7, 0xbcf5725c, 0xc53b6644, + 0x347efb5b, 0x7629438b, 0xdcc623cb, 0x68fcedb6, 0x63f1e4b8, + 0xcadc31d7, 0x10856342, 0x40229713, 0x2011c684, 0x7d244a85, + 0xf83dbbd2, 0x1132f9ae, 0x6da129c7, 0x4b2f9e1d, 0xf330b2dc, + 0xec52860d, 0xd0e3c177, 0x6c16b32b, 0x99b970a9, 0xfa489411, + 0x2264e947, 0xc48cfca8, 0x1a3ff0a0, 0xd82c7d56, 0xef903322, + 0xc74e4987, 0xc1d138d9, 0xfea2ca8c, 0x360bd498, 0xcf81f5a6, + 0x28de7aa5, 0x268eb7da, 0xa4bfad3f, 0xe49d3a2c, 0x0d927850, + 0x9bcc5f6a, 0x62467e54, 0xc2138df6, 0xe8b8d890, 0x5ef7392e, + 0xf5afc382, 0xbe805d9f, 0x7c93d069, 0xa92dd56f, 0xb31225cf, + 0x3b99acc8, 0xa77d1810, 0x6e639ce8, 0x7bbb3bdb, 0x097826cd, + 0xf418596e, 0x01b79aec, 0xa89a4f83, 0x656e95e6, 0x7ee6ffaa, + 0x08cfbc21, 0xe6e815ef, 0xd99be7ba, 0xce366f4a, 0xd4099fea, + 0xd67cb029, 0xafb2a431, 0x31233f2a, 0x3094a5c6, 0xc066a235, + 0x37bc4e74, 0xa6ca82fc, 0xb0d090e0, 0x15d8a733, 0x4a9804f1, + 0xf7daec41, 0x0e50cd7f, 0x2ff69117, 0x8dd64d76, 0x4db0ef43, + 0x544daacc, 0xdf0496e4, 0xe3b5d19e, 0x1b886a4c, 0xb81f2cc1, + 0x7f516546, 0x04ea5e9d, 0x5d358c01, 0x737487fa, 0x2e410bfb, + 0x5a1d67b3, 0x52d2db92, 0x335610e9, 0x1347d66d, 0x8c61d79a, + 0x7a0ca137, 0x8e14f859, 0x893c13eb, 0xee27a9ce, 0x35c961b7, + 0xede51ce1, 0x3cb1477a, 0x59dfd29c, 0x3f73f255, 0x79ce1418, + 0xbf37c773, 0xeacdf753, 0x5baafd5f, 0x146f3ddf, 0x86db4478, + 0x81f3afca, 0x3ec468b9, 0x2c342438, 0x5f40a3c2, 0x72c31d16, + 0x0c25e2bc, 0x8b493c28, 0x41950dff, 0x7101a839, 0xdeb30c08, + 0x9ce4b4d8, 0x90c15664, 0x6184cb7b, 0x70b632d5, 0x745c6c48, + 0x4257b8d0 + }; + + private uint Shift( + uint r, + int shift) + { + return (r >> shift) | (r << (32 - shift)); + } + + /* multiply four bytes in GF(2^8) by 'x' {02} in parallel */ + + private const uint m1 = 0x80808080; + private const uint m2 = 0x7f7f7f7f; + private const uint m3 = 0x0000001b; + + private uint FFmulX( + uint x) + { + return ((x & m2) << 1) ^ (((x & m1) >> 7) * m3); + } + + /* + The following defines provide alternative definitions of FFmulX that might + give improved performance if a fast 32-bit multiply is not available. + + private int FFmulX(int x) { int u = x & m1; u |= (u >> 1); return ((x & m2) << 1) ^ ((u >>> 3) | (u >>> 6)); } + private static final int m4 = 0x1b1b1b1b; + private int FFmulX(int x) { int u = x & m1; return ((x & m2) << 1) ^ ((u - (u >>> 7)) & m4); } + + */ + + private uint Inv_Mcol( + uint x) + { + uint f2 = FFmulX(x); + uint f4 = FFmulX(f2); + uint f8 = FFmulX(f4); + uint f9 = x ^ f8; + + return f2 ^ f4 ^ f8 ^ Shift(f2 ^ f9, 8) ^ Shift(f4 ^ f9, 16) ^ Shift(f9, 24); + } + + private uint SubWord( + uint x) + { + return (uint)S[x&255] + | (((uint)S[(x>>8)&255]) << 8) + | (((uint)S[(x>>16)&255]) << 16) + | (((uint)S[(x>>24)&255]) << 24); + } + + /** + * Calculate the necessary round keys + * The number of calculations depends on key size and block size + * AES specified a fixed block size of 128 bits and key sizes 128/192/256 bits + * This code is written assuming those are the only possible values + */ + private uint[,] GenerateWorkingKey( + byte[] key, + bool forEncryption) + { + int KC = key.Length / 4; // key length in words + int t; + + if ((KC != 4) && (KC != 6) && (KC != 8)) + throw new ArgumentException("Key length not 128/192/256 bits."); + + ROUNDS = KC + 6; // This is not always true for the generalized Rijndael that allows larger block sizes + uint[,] W = new uint[ROUNDS+1, 4]; // 4 words in a block + + // + // copy the key into the round key array + // + + t = 0; + for (int i = 0; i < key.Length; t++) + { + W[t >> 2, t & 3] = Pack.LE_To_UInt32(key, i); + i+=4; + } + + // + // while not enough round key material calculated + // calculate new values + // + int k = (ROUNDS + 1) << 2; + for (int i = KC; (i < k); i++) + { + uint temp = W[(i-1)>>2, (i-1)&3]; + if ((i % KC) == 0) + { + temp = SubWord(Shift(temp, 8)) ^ rcon[(i / KC)-1]; + } + else if ((KC > 6) && ((i % KC) == 4)) + { + temp = SubWord(temp); + } + + W[i>>2, i&3] = W[(i - KC)>>2, (i-KC)&3] ^ temp; + } + + if (!forEncryption) + { + for (int j = 1; j < ROUNDS; j++) + { + for (int i = 0; i < 4; i++) + { + W[j, i] = Inv_Mcol(W[j, i]); + } + } + } + + return W; + } + + private int ROUNDS; + private uint[,] WorkingKey; + private uint C0, C1, C2, C3; + private bool forEncryption; + + private const int BLOCK_SIZE = 16; + + /** + * default constructor - 128 bit block size. + */ + public AesEngine() + { + } + + /** + * initialise an AES cipher. + * + * @param forEncryption whether or not we are for encryption. + * @param parameters the parameters required to set up the cipher. + * @exception ArgumentException if the parameters argument is + * inappropriate. + */ + public void Init( + bool forEncryption, + ICipherParameters parameters) + { + KeyParameter keyParameter = parameters as KeyParameter; + + if (keyParameter == null) + throw new ArgumentException("invalid parameter passed to AES init - " + parameters.GetType().Name); + + WorkingKey = GenerateWorkingKey(keyParameter.GetKey(), forEncryption); + + this.forEncryption = forEncryption; + } + + public string AlgorithmName + { + get { return "AES"; } + } + + public bool IsPartialBlockOkay + { + get { return false; } + } + + public int GetBlockSize() + { + return BLOCK_SIZE; + } + + public int ProcessBlock( + byte[] input, + int inOff, + byte[] output, + int outOff) + { + if (WorkingKey == null) + { + throw new InvalidOperationException("AES engine not initialised"); + } + + if ((inOff + (32 / 2)) > input.Length) + { + throw new DataLengthException("input buffer too short"); + } + + if ((outOff + (32 / 2)) > output.Length) + { + throw new DataLengthException("output buffer too short"); + } + + UnPackBlock(input, inOff); + + if (forEncryption) + { + EncryptBlock(WorkingKey); + } + else + { + DecryptBlock(WorkingKey); + } + + PackBlock(output, outOff); + + return BLOCK_SIZE; + } + + public void Reset() + { + } + + private void UnPackBlock( + byte[] bytes, + int off) + { + C0 = Pack.LE_To_UInt32(bytes, off); + C1 = Pack.LE_To_UInt32(bytes, off + 4); + C2 = Pack.LE_To_UInt32(bytes, off + 8); + C3 = Pack.LE_To_UInt32(bytes, off + 12); + } + + private void PackBlock( + byte[] bytes, + int off) + { + Pack.UInt32_To_LE(C0, bytes, off); + Pack.UInt32_To_LE(C1, bytes, off + 4); + Pack.UInt32_To_LE(C2, bytes, off + 8); + Pack.UInt32_To_LE(C3, bytes, off + 12); + } + + private void EncryptBlock( + uint[,] KW) + { + uint r, r0, r1, r2, r3; + + C0 ^= KW[0, 0]; + C1 ^= KW[0, 1]; + C2 ^= KW[0, 2]; + C3 ^= KW[0, 3]; + + for (r = 1; r < ROUNDS - 1;) + { + r0 = T0[C0&255] ^ Shift(T0[(C1>>8)&255], 24) ^ Shift(T0[(C2>>16)&255],16) ^ Shift(T0[(C3>>24)&255],8) ^ KW[r,0]; + r1 = T0[C1&255] ^ Shift(T0[(C2>>8)&255], 24) ^ Shift(T0[(C3>>16)&255], 16) ^ Shift(T0[(C0>>24)&255], 8) ^ KW[r,1]; + r2 = T0[C2&255] ^ Shift(T0[(C3>>8)&255], 24) ^ Shift(T0[(C0>>16)&255], 16) ^ Shift(T0[(C1>>24)&255], 8) ^ KW[r,2]; + r3 = T0[C3&255] ^ Shift(T0[(C0>>8)&255], 24) ^ Shift(T0[(C1>>16)&255], 16) ^ Shift(T0[(C2>>24)&255], 8) ^ KW[r++,3]; + C0 = T0[r0&255] ^ Shift(T0[(r1>>8)&255], 24) ^ Shift(T0[(r2>>16)&255], 16) ^ Shift(T0[(r3>>24)&255], 8) ^ KW[r,0]; + C1 = T0[r1&255] ^ Shift(T0[(r2>>8)&255], 24) ^ Shift(T0[(r3>>16)&255], 16) ^ Shift(T0[(r0>>24)&255], 8) ^ KW[r,1]; + C2 = T0[r2&255] ^ Shift(T0[(r3>>8)&255], 24) ^ Shift(T0[(r0>>16)&255], 16) ^ Shift(T0[(r1>>24)&255], 8) ^ KW[r,2]; + C3 = T0[r3&255] ^ Shift(T0[(r0>>8)&255], 24) ^ Shift(T0[(r1>>16)&255], 16) ^ Shift(T0[(r2>>24)&255], 8) ^ KW[r++,3]; + } + + r0 = T0[C0&255] ^ Shift(T0[(C1>>8)&255], 24) ^ Shift(T0[(C2>>16)&255], 16) ^ Shift(T0[(C3>>24)&255], 8) ^ KW[r,0]; + r1 = T0[C1&255] ^ Shift(T0[(C2>>8)&255], 24) ^ Shift(T0[(C3>>16)&255], 16) ^ Shift(T0[(C0>>24)&255], 8) ^ KW[r,1]; + r2 = T0[C2&255] ^ Shift(T0[(C3>>8)&255], 24) ^ Shift(T0[(C0>>16)&255], 16) ^ Shift(T0[(C1>>24)&255], 8) ^ KW[r,2]; + r3 = T0[C3&255] ^ Shift(T0[(C0>>8)&255], 24) ^ Shift(T0[(C1>>16)&255], 16) ^ Shift(T0[(C2>>24)&255], 8) ^ KW[r++,3]; + + // the final round's table is a simple function of S so we don't use a whole other four tables for it + + C0 = (uint)S[r0&255] ^ (((uint)S[(r1>>8)&255])<<8) ^ (((uint)S[(r2>>16)&255])<<16) ^ (((uint)S[(r3>>24)&255])<<24) ^ KW[r,0]; + C1 = (uint)S[r1&255] ^ (((uint)S[(r2>>8)&255])<<8) ^ (((uint)S[(r3>>16)&255])<<16) ^ (((uint)S[(r0>>24)&255])<<24) ^ KW[r,1]; + C2 = (uint)S[r2&255] ^ (((uint)S[(r3>>8)&255])<<8) ^ (((uint)S[(r0>>16)&255])<<16) ^ (((uint)S[(r1>>24)&255])<<24) ^ KW[r,2]; + C3 = (uint)S[r3&255] ^ (((uint)S[(r0>>8)&255])<<8) ^ (((uint)S[(r1>>16)&255])<<16) ^ (((uint)S[(r2>>24)&255])<<24) ^ KW[r,3]; + } + + private void DecryptBlock( + uint[,] KW) + { + int r; + uint r0, r1, r2, r3; + + C0 ^= KW[ROUNDS,0]; + C1 ^= KW[ROUNDS,1]; + C2 ^= KW[ROUNDS,2]; + C3 ^= KW[ROUNDS,3]; + + for (r = ROUNDS-1; r>1;) + { + r0 = Tinv0[C0&255] ^ Shift(Tinv0[(C3>>8)&255], 24) ^ Shift(Tinv0[(C2>>16)&255], 16) ^ Shift(Tinv0[(C1>>24)&255], 8) ^ KW[r,0]; + r1 = Tinv0[C1&255] ^ Shift(Tinv0[(C0>>8)&255], 24) ^ Shift(Tinv0[(C3>>16)&255], 16) ^ Shift(Tinv0[(C2>>24)&255], 8) ^ KW[r,1]; + r2 = Tinv0[C2&255] ^ Shift(Tinv0[(C1>>8)&255], 24) ^ Shift(Tinv0[(C0>>16)&255], 16) ^ Shift(Tinv0[(C3>>24)&255], 8) ^ KW[r,2]; + r3 = Tinv0[C3&255] ^ Shift(Tinv0[(C2>>8)&255], 24) ^ Shift(Tinv0[(C1>>16)&255], 16) ^ Shift(Tinv0[(C0>>24)&255], 8) ^ KW[r--,3]; + C0 = Tinv0[r0&255] ^ Shift(Tinv0[(r3>>8)&255], 24) ^ Shift(Tinv0[(r2>>16)&255], 16) ^ Shift(Tinv0[(r1>>24)&255], 8) ^ KW[r,0]; + C1 = Tinv0[r1&255] ^ Shift(Tinv0[(r0>>8)&255], 24) ^ Shift(Tinv0[(r3>>16)&255], 16) ^ Shift(Tinv0[(r2>>24)&255], 8) ^ KW[r,1]; + C2 = Tinv0[r2&255] ^ Shift(Tinv0[(r1>>8)&255], 24) ^ Shift(Tinv0[(r0>>16)&255], 16) ^ Shift(Tinv0[(r3>>24)&255], 8) ^ KW[r,2]; + C3 = Tinv0[r3&255] ^ Shift(Tinv0[(r2>>8)&255], 24) ^ Shift(Tinv0[(r1>>16)&255], 16) ^ Shift(Tinv0[(r0>>24)&255], 8) ^ KW[r--,3]; + } + + r0 = Tinv0[C0&255] ^ Shift(Tinv0[(C3>>8)&255], 24) ^ Shift(Tinv0[(C2>>16)&255], 16) ^ Shift(Tinv0[(C1>>24)&255], 8) ^ KW[r,0]; + r1 = Tinv0[C1&255] ^ Shift(Tinv0[(C0>>8)&255], 24) ^ Shift(Tinv0[(C3>>16)&255], 16) ^ Shift(Tinv0[(C2>>24)&255], 8) ^ KW[r,1]; + r2 = Tinv0[C2&255] ^ Shift(Tinv0[(C1>>8)&255], 24) ^ Shift(Tinv0[(C0>>16)&255], 16) ^ Shift(Tinv0[(C3>>24)&255], 8) ^ KW[r,2]; + r3 = Tinv0[C3&255] ^ Shift(Tinv0[(C2>>8)&255], 24) ^ Shift(Tinv0[(C1>>16)&255], 16) ^ Shift(Tinv0[(C0>>24)&255], 8) ^ KW[r,3]; + + // the final round's table is a simple function of Si so we don't use a whole other four tables for it + + C0 = (uint)Si[r0&255] ^ (((uint)Si[(r3>>8)&255])<<8) ^ (((uint)Si[(r2>>16)&255])<<16) ^ (((uint)Si[(r1>>24)&255])<<24) ^ KW[0,0]; + C1 = (uint)Si[r1&255] ^ (((uint)Si[(r0>>8)&255])<<8) ^ (((uint)Si[(r3>>16)&255])<<16) ^ (((uint)Si[(r2>>24)&255])<<24) ^ KW[0,1]; + C2 = (uint)Si[r2&255] ^ (((uint)Si[(r1>>8)&255])<<8) ^ (((uint)Si[(r0>>16)&255])<<16) ^ (((uint)Si[(r3>>24)&255])<<24) ^ KW[0,2]; + C3 = (uint)Si[r3&255] ^ (((uint)Si[(r2>>8)&255])<<8) ^ (((uint)Si[(r1>>16)&255])<<16) ^ (((uint)Si[(r0>>24)&255])<<24) ^ KW[0,3]; + } + } +} |