[proxmark3-svn] / tools / nonce2key / crypto1.c

/*  crypto1.c

    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License
    as published by the Free Software Foundation; either version 2
    of the License, or (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
    MA  02110-1301, US

    Copyright (C) 2008-2008 bla <blapost@gmail.com>
*/
#include "crapto1.h"
#include <stdlib.h>

#define SWAPENDIAN(x)\
	(x = (x >> 8 & 0xff00ff) | (x & 0xff00ff) << 8, x = x >> 16 | x << 16)

struct Crypto1State * crypto1_create(uint64_t key)
{
	struct Crypto1State *s = malloc(sizeof(*s));
	int i;

	for(i = 47;s && i > 0; i -= 2) {
		s->odd  = s->odd  << 1 | BIT(key, (i - 1) ^ 7);
		s->even = s->even << 1 | BIT(key, i ^ 7);
	}
	return s;
}
void crypto1_destroy(struct Crypto1State *state)
{
	free(state);
}
void crypto1_get_lfsr(struct Crypto1State *state, uint64_t *lfsr)
{
	int i;
	for(*lfsr = 0, i = 23; i >= 0; --i) {
		*lfsr = *lfsr << 1 | BIT(state->odd, i ^ 3);
		*lfsr = *lfsr << 1 | BIT(state->even, i ^ 3);
	}
}
uint8_t crypto1_bit(struct Crypto1State *s, uint8_t in, int is_encrypted)
{
	uint32_t feedin;
	uint8_t ret = filter(s->odd);

	feedin  = ret & !!is_encrypted;
	feedin ^= !!in;
	feedin ^= LF_POLY_ODD & s->odd;
	feedin ^= LF_POLY_EVEN & s->even;
	s->even = s->even << 1 | parity(feedin);

	s->odd ^= (s->odd ^= s->even, s->even ^= s->odd);

	return ret;
}
uint8_t crypto1_byte(struct Crypto1State *s, uint8_t in, int is_encrypted)
{
	uint8_t i, ret = 0;

	for (i = 0; i < 8; ++i)
		ret |= crypto1_bit(s, BIT(in, i), is_encrypted) << i;

	return ret;
}
uint32_t crypto1_word(struct Crypto1State *s, uint32_t in, int is_encrypted)
{
	uint32_t i, ret = 0;

	for (i = 0; i < 4; ++i, in <<= 8)
		ret = ret << 8 | crypto1_byte(s, in >> 24, is_encrypted);

	return ret;
}

/* prng_successor
 * helper used to obscure the keystream during authentication
 */
uint32_t prng_successor(uint32_t x, uint32_t n)
{
	SWAPENDIAN(x);
	while(n--)
		x = x >> 1 | (x >> 16 ^ x >> 18 ^ x >> 19 ^ x >> 21) << 31;

	return SWAPENDIAN(x);
}
Commit	Line	Data
93f57590	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	}