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20f9a2a1 M |
1 | /* crypto1.c |
2 | ||
9cefee6f | 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> | |
20f9a2a1 M |
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 | void crypto1_create(struct Crypto1State *s, 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; | |
36 | } | |
37 | void crypto1_destroy(struct Crypto1State *state) | |
38 | { | |
39 | // free(state); | |
9cefee6f | 40 | state->odd = 0; |
41 | state->even = 0; | |
20f9a2a1 M |
42 | } |
43 | void crypto1_get_lfsr(struct Crypto1State *state, uint64_t *lfsr) | |
44 | { | |
45 | int i; | |
46 | for(*lfsr = 0, i = 23; i >= 0; --i) { | |
47 | *lfsr = *lfsr << 1 | BIT(state->odd, i ^ 3); | |
48 | *lfsr = *lfsr << 1 | BIT(state->even, i ^ 3); | |
49 | } | |
50 | } | |
51 | uint8_t crypto1_bit(struct Crypto1State *s, uint8_t in, int is_encrypted) | |
52 | { | |
53 | uint32_t feedin; | |
9cefee6f | 54 | uint32_t tmp; |
20f9a2a1 M |
55 | uint8_t ret = filter(s->odd); |
56 | ||
57 | feedin = ret & !!is_encrypted; | |
58 | feedin ^= !!in; | |
59 | feedin ^= LF_POLY_ODD & s->odd; | |
60 | feedin ^= LF_POLY_EVEN & s->even; | |
61 | s->even = s->even << 1 | parity(feedin); | |
62 | ||
9cefee6f | 63 | tmp = s->odd; |
64 | s->odd = s->even; | |
65 | s->even = tmp; | |
20f9a2a1 M |
66 | |
67 | return ret; | |
68 | } | |
69 | uint8_t crypto1_byte(struct Crypto1State *s, uint8_t in, int is_encrypted) | |
70 | { | |
71 | uint8_t i, ret = 0; | |
72 | ||
73 | for (i = 0; i < 8; ++i) | |
74 | ret |= crypto1_bit(s, BIT(in, i), is_encrypted) << i; | |
75 | ||
76 | return ret; | |
77 | } | |
78 | uint32_t crypto1_word(struct Crypto1State *s, uint32_t in, int is_encrypted) | |
79 | { | |
80 | uint32_t i, ret = 0; | |
81 | ||
82 | for (i = 0; i < 32; ++i) | |
83 | ret |= crypto1_bit(s, BEBIT(in, i), is_encrypted) << (i ^ 24); | |
84 | ||
85 | return ret; | |
86 | } | |
87 | ||
88 | /* prng_successor | |
89 | * helper used to obscure the keystream during authentication | |
90 | */ | |
91 | uint32_t prng_successor(uint32_t x, uint32_t n) | |
92 | { | |
93 | SWAPENDIAN(x); | |
94 | while(n--) | |
95 | x = x >> 1 | (x >> 16 ^ x >> 18 ^ x >> 19 ^ x >> 21) << 31; | |
96 | ||
97 | return SWAPENDIAN(x); | |
98 | } |