]>
git.zerfleddert.de Git - proxmark3-svn/blob - tools/nonce2key/crypto1.c
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.
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.
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,
18 Copyright (C) 2008-2008 bla <blapost@gmail.com>
23 #define SWAPENDIAN(x)\
24 (x = (x >> 8 & 0xff00ff) | (x & 0xff00ff) << 8, x = x >> 16 | x << 16)
26 struct Crypto1State
* crypto1_create(uint64_t key
)
28 struct Crypto1State
*s
= malloc(sizeof(*s
));
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);
37 void crypto1_destroy(struct Crypto1State
*state
)
41 void crypto1_get_lfsr(struct Crypto1State
*state
, uint64_t *lfsr
)
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);
49 uint8_t crypto1_bit(struct Crypto1State
*s
, uint8_t in
, int is_encrypted
)
52 uint8_t ret
= filter(s
->odd
);
54 feedin
= ret
& !!is_encrypted
;
56 feedin
^= LF_POLY_ODD
& s
->odd
;
57 feedin
^= LF_POLY_EVEN
& s
->even
;
58 s
->even
= s
->even
<< 1 | parity(feedin
);
60 s
->odd
^= (s
->odd
^= s
->even
, s
->even
^= s
->odd
);
64 uint8_t crypto1_byte(struct Crypto1State
*s
, uint8_t in
, int is_encrypted
)
68 for (i
= 0; i
< 8; ++i
)
69 ret
|= crypto1_bit(s
, BIT(in
, i
), is_encrypted
) << i
;
73 uint32_t crypto1_word(struct Crypto1State
*s
, uint32_t in
, int is_encrypted
)
77 for (i
= 0; i
< 4; ++i
, in
<<= 8)
78 ret
= ret
<< 8 | crypto1_byte(s
, in
>> 24, is_encrypted
);
84 * helper used to obscure the keystream during authentication
86 uint32_t prng_successor(uint32_t x
, uint32_t n
)
90 x
= x
>> 1 | (x
>> 16 ^ x
>> 18 ^ x
>> 19 ^ x
>> 21) << 31;