/************************************************* * XTEA Source File * * (C) 1999-2007 The Botan Project * *************************************************/ #include #include #include namespace Botan { /************************************************* * XTEA Encryption * *************************************************/ void XTEA::enc(const byte in[], byte out[]) const { u32bit L = load_be(in, 0), R = load_be(in, 1); for(u32bit j = 0; j != 32; ++j) { L += (((R << 4) ^ (R >> 5)) + R) ^ EK[2*j]; R += (((L << 4) ^ (L >> 5)) + L) ^ EK[2*j+1]; } store_be(out, L, R); } /************************************************* * XTEA Decryption * *************************************************/ void XTEA::dec(const byte in[], byte out[]) const { u32bit L = load_be(in, 0), R = load_be(in, 1); for(u32bit j = 32; j > 0; --j) { R -= (((L << 4) ^ (L >> 5)) + L) ^ EK[2*j - 1]; L -= (((R << 4) ^ (R >> 5)) + R) ^ EK[2*j - 2]; } store_be(out, L, R); } /************************************************* * XTEA Key Schedule * *************************************************/ void XTEA::key(const byte key[], u32bit) { static const u32bit DELTAS[64] = { 0x00000000, 0x9E3779B9, 0x9E3779B9, 0x3C6EF372, 0x3C6EF372, 0xDAA66D2B, 0xDAA66D2B, 0x78DDE6E4, 0x78DDE6E4, 0x1715609D, 0x1715609D, 0xB54CDA56, 0xB54CDA56, 0x5384540F, 0x5384540F, 0xF1BBCDC8, 0xF1BBCDC8, 0x8FF34781, 0x8FF34781, 0x2E2AC13A, 0x2E2AC13A, 0xCC623AF3, 0xCC623AF3, 0x6A99B4AC, 0x6A99B4AC, 0x08D12E65, 0x08D12E65, 0xA708A81E, 0xA708A81E, 0x454021D7, 0x454021D7, 0xE3779B90, 0xE3779B90, 0x81AF1549, 0x81AF1549, 0x1FE68F02, 0x1FE68F02, 0xBE1E08BB, 0xBE1E08BB, 0x5C558274, 0x5C558274, 0xFA8CFC2D, 0xFA8CFC2D, 0x98C475E6, 0x98C475E6, 0x36FBEF9F, 0x36FBEF9F, 0xD5336958, 0xD5336958, 0x736AE311, 0x736AE311, 0x11A25CCA, 0x11A25CCA, 0xAFD9D683, 0xAFD9D683, 0x4E11503C, 0x4E11503C, 0xEC48C9F5, 0xEC48C9F5, 0x8A8043AE, 0x8A8043AE, 0x28B7BD67, 0x28B7BD67, 0xC6EF3720 }; static const byte KEY_INDEX[64] = { 0x00, 0x03, 0x01, 0x02, 0x02, 0x01, 0x03, 0x00, 0x00, 0x00, 0x01, 0x03, 0x02, 0x02, 0x03, 0x01, 0x00, 0x00, 0x01, 0x00, 0x02, 0x03, 0x03, 0x02, 0x00, 0x01, 0x01, 0x01, 0x02, 0x00, 0x03, 0x03, 0x00, 0x02, 0x01, 0x01, 0x02, 0x01, 0x03, 0x00, 0x00, 0x03, 0x01, 0x02, 0x02, 0x01, 0x03, 0x01, 0x00, 0x00, 0x01, 0x03, 0x02, 0x02, 0x03, 0x02, 0x00, 0x01, 0x01, 0x00, 0x02, 0x03, 0x03, 0x02 }; SecureBuffer UK; for(u32bit j = 0; j != 4; ++j) UK[j] = load_be(key, j); for(u32bit j = 0; j != 64; ++j) EK[j] = DELTAS[j] + UK[KEY_INDEX[j]]; } }