projects / proxmark3-svn / blame
| Commit | Line | Data |
|---|---|---|
| f89c7050 M |
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 < 4; ++i, in <<= 8) | |
| 78 | ret = ret << 8 | crypto1_byte(s, in >> 24, is_encrypted); | |
| 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 | } |