/************************************************* * GOST Source File * * (C) 1999-2007 Jack Lloyd * *************************************************/ #include <botan/gost.h> #include <botan/loadstor.h> namespace Botan { /************************************************* * GOST Encryption * *************************************************/ void GOST::enc(const byte in[], byte out[]) const { u32bit N1 = load_le<u32bit>(in, 0), N2 = load_le<u32bit>(in, 1); for(u32bit j = 0; j != 32; j += 2) { u32bit T0; T0 = N1 + EK[j]; N2 ^= SBOX1[get_byte(0, T0)] | SBOX2[get_byte(1, T0)] | SBOX3[get_byte(2, T0)] | SBOX4[get_byte(3, T0)]; T0 = N2 + EK[j+1]; N1 ^= SBOX1[get_byte(0, T0)] | SBOX2[get_byte(1, T0)] | SBOX3[get_byte(2, T0)] | SBOX4[get_byte(3, T0)]; } store_le(out, N2, N1); } /************************************************* * GOST Decryption * *************************************************/ void GOST::dec(const byte in[], byte out[]) const { u32bit N1 = load_le<u32bit>(in, 0), N2 = load_le<u32bit>(in, 1); for(u32bit j = 0; j != 32; j += 2) { u32bit T0; T0 = N1 + EK[31-j]; N2 ^= SBOX1[get_byte(0, T0)] | SBOX2[get_byte(1, T0)] | SBOX3[get_byte(2, T0)] | SBOX4[get_byte(3, T0)]; T0 = N2 + EK[30-j]; N1 ^= SBOX1[get_byte(0, T0)] | SBOX2[get_byte(1, T0)] | SBOX3[get_byte(2, T0)] | SBOX4[get_byte(3, T0)]; } store_le(out, N2, N1); } /************************************************* * GOST Key Schedule * *************************************************/ void GOST::key(const byte key[], u32bit) { for(u32bit j = 0; j != 8; ++j) { u32bit K = load_le<u32bit>(key, j); EK[j] = EK[j+8] = EK[j+16] = K; } for(u32bit j = 24; j != 32; ++j) EK[j] = EK[7-(j-24)]; } }