1 /* threefish512_dec.c */
3 This file is part of the AVR-Crypto-Lib.
4 Copyright (C) 2009 Daniel Otte (daniel.otte@rub.de)
6 This program is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation, either version 3 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
21 * \email daniel.otte@rub.de
23 * \license GPLv3 or later
31 #include "threefish.h"
34 #define X(a) (((uint64_t*)data)[(a)])
38 void permute_inv8(void *data){
51 void add_key_8(void *data, const threefish512_ctx_t *ctx, uint8_t s){
54 X(i) -= ctx->k[(s+i)%9];
56 X(5) -= ctx->k[(s+5)%9] + ctx->t[s%3];
57 X(6) -= ctx->k[(s+6)%9] + ctx->t[(s+1)%3];
58 X(7) -= ctx->k[(s+7)%9] + s;
61 void threefish512_dec(void *data, const threefish512_ctx_t *ctx){
63 uint8_t r0[8] = {0x41, 0x4b, 0x59, 0x41, 0x32, 0x42, 0x60, 0x5a};
64 uint8_t r1[8] = {0x63, 0x32, 0x33, 0x61, 0x14, 0x2a, 0x24, 0x4a};
65 uint8_t r2[8] = {0x59, 0x13, 0x51, 0x10, 0x72, 0x29, 0x53, 0x62};
66 uint8_t r3[8] = {0x43, 0x11, 0x2a, 0x52, 0x19, 0x33, 0x49, 0x7b};
69 add_key_8(data, ctx, s);
73 threefish_invmix((uint8_t*)data + 0, r0[i%8]);
74 threefish_invmix((uint8_t*)data + 16, r1[i%8]);
75 threefish_invmix((uint8_t*)data + 32, r2[i%8]);
76 threefish_invmix((uint8_t*)data + 48, r3[i%8]);
79 add_key_8(data, ctx, s);