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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 | ||
22 | #include <stdlib.h> | |
23 | #include "parity.h" | |
24 | ||
25 | #define SWAPENDIAN(x)\ | |
26 | (x = (x >> 8 & 0xff00ff) | (x & 0xff00ff) << 8, x = x >> 16 | x << 16) | |
27 | ||
28 | #if defined(__arm__) && !defined(__linux__) && !defined(_WIN32) && !defined(__APPLE__) // bare metal ARM Proxmark lacks malloc()/free() | |
29 | void crypto1_create(struct Crypto1State *s, uint64_t key) | |
30 | { | |
31 | int i; | |
32 | ||
33 | for(i = 47;s && i > 0; i -= 2) { | |
34 | s->odd = s->odd << 1 | BIT(key, (i - 1) ^ 7); | |
35 | s->even = s->even << 1 | BIT(key, i ^ 7); | |
36 | } | |
37 | return; | |
38 | } | |
39 | void crypto1_destroy(struct Crypto1State *state) | |
40 | { | |
41 | state->odd = 0; | |
42 | state->even = 0; | |
43 | } | |
44 | #else | |
45 | struct Crypto1State * crypto1_create(uint64_t key) | |
46 | { | |
47 | struct Crypto1State *s = malloc(sizeof(*s)); | |
48 | int i; | |
49 | ||
50 | for(i = 47;s && i > 0; i -= 2) { | |
51 | s->odd = s->odd << 1 | BIT(key, (i - 1) ^ 7); | |
52 | s->even = s->even << 1 | BIT(key, i ^ 7); | |
53 | } | |
54 | return s; | |
55 | } | |
56 | void crypto1_destroy(struct Crypto1State *state) | |
57 | { | |
58 | free(state); | |
59 | } | |
60 | #endif | |
61 | void crypto1_get_lfsr(struct Crypto1State *state, uint64_t *lfsr) | |
62 | { | |
63 | int i; | |
64 | for(*lfsr = 0, i = 23; i >= 0; --i) { | |
65 | *lfsr = *lfsr << 1 | BIT(state->odd, i ^ 3); | |
66 | *lfsr = *lfsr << 1 | BIT(state->even, i ^ 3); | |
67 | } | |
68 | } | |
69 | uint8_t crypto1_bit(struct Crypto1State *s, uint8_t in, int is_encrypted) | |
70 | { | |
71 | uint32_t feedin, t; | |
72 | uint8_t ret = filter(s->odd); | |
73 | ||
74 | feedin = ret & !!is_encrypted; | |
75 | feedin ^= !!in; | |
76 | feedin ^= LF_POLY_ODD & s->odd; | |
77 | feedin ^= LF_POLY_EVEN & s->even; | |
78 | s->even = s->even << 1 | evenparity32(feedin); | |
79 | ||
80 | t = s->odd, s->odd = s->even, s->even = t; | |
81 | ||
82 | return ret; | |
83 | } | |
84 | uint8_t crypto1_byte(struct Crypto1State *s, uint8_t in, int is_encrypted) | |
85 | { | |
86 | uint8_t i, ret = 0; | |
87 | ||
88 | for (i = 0; i < 8; ++i) | |
89 | ret |= crypto1_bit(s, BIT(in, i), is_encrypted) << i; | |
90 | ||
91 | return ret; | |
92 | } | |
93 | uint32_t crypto1_word(struct Crypto1State *s, uint32_t in, int is_encrypted) | |
94 | { | |
95 | uint32_t i, ret = 0; | |
96 | ||
97 | for (i = 0; i < 32; ++i) | |
98 | ret |= crypto1_bit(s, BEBIT(in, i), is_encrypted) << (i ^ 24); | |
99 | ||
100 | return ret; | |
101 | } | |
102 | ||
103 | /* prng_successor | |
104 | * helper used to obscure the keystream during authentication | |
105 | */ | |
106 | uint32_t prng_successor(uint32_t x, uint32_t n) | |
107 | { | |
108 | SWAPENDIAN(x); | |
109 | while(n--) | |
110 | x = x >> 1 | (x >> 16 ^ x >> 18 ^ x >> 19 ^ x >> 21) << 31; | |
111 | ||
112 | return SWAPENDIAN(x); | |
113 | } |