| 7847961b |
1 | /* crypto1.c |
| 2 | |
| 3 | This program is free software; you can redistribute it and/or |
| 4 | modify it under the terms of the GNU General Public License |
| 5 | as published by the Free Software Foundation; either version 2 |
| 6 | of the License, or (at your option) any later version. |
| 7 | |
| 8 | This program is distributed in the hope that it will be useful, |
| 9 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 10 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 11 | GNU General Public License for more details. |
| 12 | |
| 13 | You should have received a copy of the GNU General Public License |
| 14 | along with this program; if not, write to the Free Software |
| 15 | Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, |
| 16 | MA 02110-1301, US |
| 17 | |
| 18 | Copyright (C) 2008-2008 bla <blapost@gmail.com> |
| 19 | */ |
| 20 | #include "crapto1.h" |
| 21 | #include <stdlib.h> |
| 22 | |
| 23 | #define SWAPENDIAN(x)\ |
| 24 | (x = (x >> 8 & 0xff00ff) | (x & 0xff00ff) << 8, x = x >> 16 | x << 16) |
| 25 | |
| 26 | struct Crypto1State * crypto1_create(uint64_t key) |
| 27 | { |
| 28 | struct Crypto1State *s = malloc(sizeof(*s)); |
| 29 | int i; |
| 30 | |
| 31 | for(i = 47;s && i > 0; i -= 2) { |
| 32 | s->odd = s->odd << 1 | BIT(key, (i - 1) ^ 7); |
| 33 | s->even = s->even << 1 | BIT(key, i ^ 7); |
| 34 | } |
| 35 | return s; |
| 36 | } |
| 37 | void crypto1_destroy(struct Crypto1State *state) |
| 38 | { |
| 39 | free(state); |
| 40 | } |
| 41 | void crypto1_get_lfsr(struct Crypto1State *state, uint64_t *lfsr) |
| 42 | { |
| 43 | int i; |
| 44 | for(*lfsr = 0, i = 23; i >= 0; --i) { |
| 45 | *lfsr = *lfsr << 1 | BIT(state->odd, i ^ 3); |
| 46 | *lfsr = *lfsr << 1 | BIT(state->even, i ^ 3); |
| 47 | } |
| 48 | } |
| 49 | uint8_t crypto1_bit(struct Crypto1State *s, uint8_t in, int is_encrypted) |
| 50 | { |
| 51 | uint32_t feedin; |
| 52 | uint8_t ret = filter(s->odd); |
| 53 | |
| 54 | feedin = ret & !!is_encrypted; |
| 55 | feedin ^= !!in; |
| 56 | feedin ^= LF_POLY_ODD & s->odd; |
| 57 | feedin ^= LF_POLY_EVEN & s->even; |
| 58 | s->even = s->even << 1 | parity(feedin); |
| 59 | |
| 60 | s->odd ^= (s->odd ^= s->even, s->even ^= s->odd); |
| 61 | |
| 62 | return ret; |
| 63 | } |
| 64 | uint8_t crypto1_byte(struct Crypto1State *s, uint8_t in, int is_encrypted) |
| 65 | { |
| 66 | uint8_t i, ret = 0; |
| 67 | |
| 68 | for (i = 0; i < 8; ++i) |
| 69 | ret |= crypto1_bit(s, BIT(in, i), is_encrypted) << i; |
| 70 | |
| 71 | return ret; |
| 72 | } |
| 73 | uint32_t crypto1_word(struct Crypto1State *s, uint32_t in, int is_encrypted) |
| 74 | { |
| 75 | uint32_t i, ret = 0; |
| 76 | |
| 77 | for (i = 0; i < 32; ++i) |
| 78 | ret |= crypto1_bit(s, BEBIT(in, i), is_encrypted) << (i ^ 24); |
| 79 | |
| 80 | return ret; |
| 81 | } |
| 82 | |
| 83 | /* prng_successor |
| 84 | * helper used to obscure the keystream during authentication |
| 85 | */ |
| 86 | uint32_t prng_successor(uint32_t x, uint32_t n) |
| 87 | { |
| 88 | SWAPENDIAN(x); |
| 89 | while(n--) |
| 90 | x = x >> 1 | (x >> 16 ^ x >> 18 ^ x >> 19 ^ x >> 21) << 31; |
| 91 | |
| 92 | return SWAPENDIAN(x); |
| 93 | } |
projects / proxmark3-svn / blame