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Diffstat (limited to 'botan/src/block/cast/cast256.cpp')
| -rw-r--r-- | botan/src/block/cast/cast256.cpp | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/botan/src/block/cast/cast256.cpp b/botan/src/block/cast/cast256.cpp new file mode 100644 index 0000000..22ff876 --- /dev/null +++ b/botan/src/block/cast/cast256.cpp @@ -0,0 +1,165 @@ +/* +* CAST-256 +* (C) 1999-2007 Jack Lloyd +* +* Distributed under the terms of the Botan license +*/ + +#include <botan/cast256.h> +#include <botan/loadstor.h> +#include <botan/rotate.h> + +namespace Botan { + +namespace { + +/* +* CAST-256 Round Type 1 +*/ +void round1(u32bit& out, u32bit in, u32bit mask, u32bit rot) + { + u32bit temp = rotate_left(mask + in, rot); + out ^= (CAST_SBOX1[get_byte(0, temp)] ^ CAST_SBOX2[get_byte(1, temp)]) - + CAST_SBOX3[get_byte(2, temp)] + CAST_SBOX4[get_byte(3, temp)]; + } + +/* +* CAST-256 Round Type 2 +*/ +void round2(u32bit& out, u32bit in, u32bit mask, u32bit rot) + { + u32bit temp = rotate_left(mask ^ in, rot); + out ^= (CAST_SBOX1[get_byte(0, temp)] - CAST_SBOX2[get_byte(1, temp)] + + CAST_SBOX3[get_byte(2, temp)]) ^ CAST_SBOX4[get_byte(3, temp)]; + } + +/* +* CAST-256 Round Type 3 +*/ +void round3(u32bit& out, u32bit in, u32bit mask, u32bit rot) + { + u32bit temp = rotate_left(mask - in, rot); + out ^= ((CAST_SBOX1[get_byte(0, temp)] + CAST_SBOX2[get_byte(1, temp)]) ^ + CAST_SBOX3[get_byte(2, temp)]) - CAST_SBOX4[get_byte(3, temp)]; + } + +} + +/* +* CAST-256 Encryption +*/ +void CAST_256::enc(const byte in[], byte out[]) const + { + u32bit A = load_be<u32bit>(in, 0); + u32bit B = load_be<u32bit>(in, 1); + u32bit C = load_be<u32bit>(in, 2); + u32bit D = load_be<u32bit>(in, 3); + + round1(C, D, MK[ 0], RK[ 0]); round2(B, C, MK[ 1], RK[ 1]); + round3(A, B, MK[ 2], RK[ 2]); round1(D, A, MK[ 3], RK[ 3]); + round1(C, D, MK[ 4], RK[ 4]); round2(B, C, MK[ 5], RK[ 5]); + round3(A, B, MK[ 6], RK[ 6]); round1(D, A, MK[ 7], RK[ 7]); + round1(C, D, MK[ 8], RK[ 8]); round2(B, C, MK[ 9], RK[ 9]); + round3(A, B, MK[10], RK[10]); round1(D, A, MK[11], RK[11]); + round1(C, D, MK[12], RK[12]); round2(B, C, MK[13], RK[13]); + round3(A, B, MK[14], RK[14]); round1(D, A, MK[15], RK[15]); + round1(C, D, MK[16], RK[16]); round2(B, C, MK[17], RK[17]); + round3(A, B, MK[18], RK[18]); round1(D, A, MK[19], RK[19]); + round1(C, D, MK[20], RK[20]); round2(B, C, MK[21], RK[21]); + round3(A, B, MK[22], RK[22]); round1(D, A, MK[23], RK[23]); + round1(D, A, MK[27], RK[27]); round3(A, B, MK[26], RK[26]); + round2(B, C, MK[25], RK[25]); round1(C, D, MK[24], RK[24]); + round1(D, A, MK[31], RK[31]); round3(A, B, MK[30], RK[30]); + round2(B, C, MK[29], RK[29]); round1(C, D, MK[28], RK[28]); + round1(D, A, MK[35], RK[35]); round3(A, B, MK[34], RK[34]); + round2(B, C, MK[33], RK[33]); round1(C, D, MK[32], RK[32]); + round1(D, A, MK[39], RK[39]); round3(A, B, MK[38], RK[38]); + round2(B, C, MK[37], RK[37]); round1(C, D, MK[36], RK[36]); + round1(D, A, MK[43], RK[43]); round3(A, B, MK[42], RK[42]); + round2(B, C, MK[41], RK[41]); round1(C, D, MK[40], RK[40]); + round1(D, A, MK[47], RK[47]); round3(A, B, MK[46], RK[46]); + round2(B, C, MK[45], RK[45]); round1(C, D, MK[44], RK[44]); + + store_be(out, A, B, C, D); + } + +/* +* CAST-256 Decryption +*/ +void CAST_256::dec(const byte in[], byte out[]) const + { + u32bit A = load_be<u32bit>(in, 0); + u32bit B = load_be<u32bit>(in, 1); + u32bit C = load_be<u32bit>(in, 2); + u32bit D = load_be<u32bit>(in, 3); + + round1(C, D, MK[44], RK[44]); round2(B, C, MK[45], RK[45]); + round3(A, B, MK[46], RK[46]); round1(D, A, MK[47], RK[47]); + round1(C, D, MK[40], RK[40]); round2(B, C, MK[41], RK[41]); + round3(A, B, MK[42], RK[42]); round1(D, A, MK[43], RK[43]); + round1(C, D, MK[36], RK[36]); round2(B, C, MK[37], RK[37]); + round3(A, B, MK[38], RK[38]); round1(D, A, MK[39], RK[39]); + round1(C, D, MK[32], RK[32]); round2(B, C, MK[33], RK[33]); + round3(A, B, MK[34], RK[34]); round1(D, A, MK[35], RK[35]); + round1(C, D, MK[28], RK[28]); round2(B, C, MK[29], RK[29]); + round3(A, B, MK[30], RK[30]); round1(D, A, MK[31], RK[31]); + round1(C, D, MK[24], RK[24]); round2(B, C, MK[25], RK[25]); + round3(A, B, MK[26], RK[26]); round1(D, A, MK[27], RK[27]); + round1(D, A, MK[23], RK[23]); round3(A, B, MK[22], RK[22]); + round2(B, C, MK[21], RK[21]); round1(C, D, MK[20], RK[20]); + round1(D, A, MK[19], RK[19]); round3(A, B, MK[18], RK[18]); + round2(B, C, MK[17], RK[17]); round1(C, D, MK[16], RK[16]); + round1(D, A, MK[15], RK[15]); round3(A, B, MK[14], RK[14]); + round2(B, C, MK[13], RK[13]); round1(C, D, MK[12], RK[12]); + round1(D, A, MK[11], RK[11]); round3(A, B, MK[10], RK[10]); + round2(B, C, MK[ 9], RK[ 9]); round1(C, D, MK[ 8], RK[ 8]); + round1(D, A, MK[ 7], RK[ 7]); round3(A, B, MK[ 6], RK[ 6]); + round2(B, C, MK[ 5], RK[ 5]); round1(C, D, MK[ 4], RK[ 4]); + round1(D, A, MK[ 3], RK[ 3]); round3(A, B, MK[ 2], RK[ 2]); + round2(B, C, MK[ 1], RK[ 1]); round1(C, D, MK[ 0], RK[ 0]); + + store_be(out, A, B, C, D); + } + +/* +* CAST-256 Key Schedule +*/ +void CAST_256::key_schedule(const byte key[], u32bit length) + { + SecureBuffer<u32bit, 8> TMP; + for(u32bit j = 0; j != length; ++j) + TMP[j/4] = (TMP[j/4] << 8) + key[j]; + + u32bit A = TMP[0], B = TMP[1], C = TMP[2], D = TMP[3], + E = TMP[4], F = TMP[5], G = TMP[6], H = TMP[7]; + for(u32bit j = 0; j != 48; j += 4) + { + round1(G, H, KEY_MASK[4*j+ 0], KEY_ROT[(4*j+ 0) % 32]); + round2(F, G, KEY_MASK[4*j+ 1], KEY_ROT[(4*j+ 1) % 32]); + round3(E, F, KEY_MASK[4*j+ 2], KEY_ROT[(4*j+ 2) % 32]); + round1(D, E, KEY_MASK[4*j+ 3], KEY_ROT[(4*j+ 3) % 32]); + round2(C, D, KEY_MASK[4*j+ 4], KEY_ROT[(4*j+ 4) % 32]); + round3(B, C, KEY_MASK[4*j+ 5], KEY_ROT[(4*j+ 5) % 32]); + round1(A, B, KEY_MASK[4*j+ 6], KEY_ROT[(4*j+ 6) % 32]); + round2(H, A, KEY_MASK[4*j+ 7], KEY_ROT[(4*j+ 7) % 32]); + round1(G, H, KEY_MASK[4*j+ 8], KEY_ROT[(4*j+ 8) % 32]); + round2(F, G, KEY_MASK[4*j+ 9], KEY_ROT[(4*j+ 9) % 32]); + round3(E, F, KEY_MASK[4*j+10], KEY_ROT[(4*j+10) % 32]); + round1(D, E, KEY_MASK[4*j+11], KEY_ROT[(4*j+11) % 32]); + round2(C, D, KEY_MASK[4*j+12], KEY_ROT[(4*j+12) % 32]); + round3(B, C, KEY_MASK[4*j+13], KEY_ROT[(4*j+13) % 32]); + round1(A, B, KEY_MASK[4*j+14], KEY_ROT[(4*j+14) % 32]); + round2(H, A, KEY_MASK[4*j+15], KEY_ROT[(4*j+15) % 32]); + + RK[j ] = (A % 32); + RK[j+1] = (C % 32); + RK[j+2] = (E % 32); + RK[j+3] = (G % 32); + MK[j ] = H; + MK[j+1] = F; + MK[j+2] = D; + MK[j+3] = B; + } + } + +} |