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https://github.com/Proxmark/proxmark3.git
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478 lines
13 KiB
C
Executable file
478 lines
13 KiB
C
Executable file
/* crapto1.c
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor,
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Boston, MA 02110-1301, US$
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Copyright (C) 2008-2008 bla <blapost@gmail.com>
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*/
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#include "crapto1.h"
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#include <stdlib.h>
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#if !defined LOWMEM && defined __GNUC__
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static uint8_t filterlut[1 << 20];
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static void __attribute__((constructor)) fill_lut()
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{
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uint32_t i;
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for(i = 0; i < 1 << 20; ++i)
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filterlut[i] = filter(i);
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}
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#define filter(x) (filterlut[(x) & 0xfffff])
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#endif
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static void quicksort(uint32_t* const start, uint32_t* const stop)
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{
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uint32_t *it = start + 1, *rit = stop;
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if(it > rit)
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return;
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while(it < rit)
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if(*it <= *start)
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++it;
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else if(*rit > *start)
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--rit;
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else
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*it ^= (*it ^= *rit, *rit ^= *it);
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if(*rit >= *start)
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--rit;
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if(rit != start)
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*rit ^= (*rit ^= *start, *start ^= *rit);
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quicksort(start, rit - 1);
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quicksort(rit + 1, stop);
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}
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/** binsearch
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* Binary search for the first occurence of *stop's MSB in sorted [start,stop]
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*/
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static inline uint32_t* binsearch(uint32_t *start, uint32_t *stop)
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{
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uint32_t mid, val = *stop & 0xff000000;
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while(start != stop)
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if(start[mid = (stop - start) >> 1] > val)
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stop = &start[mid];
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else
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start += mid + 1;
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return start;
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}
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/** update_contribution
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* helper, calculates the partial linear feedback contributions and puts in MSB
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*/
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static inline void
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update_contribution(uint32_t *item, const uint32_t mask1, const uint32_t mask2)
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{
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uint32_t p = *item >> 25;
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p = p << 1 | parity(*item & mask1);
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p = p << 1 | parity(*item & mask2);
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*item = p << 24 | (*item & 0xffffff);
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}
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/** extend_table
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* using a bit of the keystream extend the table of possible lfsr states
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*/
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static inline void
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extend_table(uint32_t *tbl, uint32_t **end, int bit, int m1, int m2, uint32_t in)
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{
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in <<= 24;
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for(*tbl <<= 1; tbl <= *end; *++tbl <<= 1)
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if(filter(*tbl) ^ filter(*tbl | 1)) {
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*tbl |= filter(*tbl) ^ bit;
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update_contribution(tbl, m1, m2);
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*tbl ^= in;
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} else if(filter(*tbl) == bit) {
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*++*end = tbl[1];
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tbl[1] = tbl[0] | 1;
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update_contribution(tbl, m1, m2);
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*tbl++ ^= in;
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update_contribution(tbl, m1, m2);
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*tbl ^= in;
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} else
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*tbl-- = *(*end)--;
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}
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/** extend_table_simple
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* using a bit of the keystream extend the table of possible lfsr states
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*/
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static inline void extend_table_simple(uint32_t *tbl, uint32_t **end, int bit)
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{
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for(*tbl <<= 1; tbl <= *end; *++tbl <<= 1)
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if(filter(*tbl) ^ filter(*tbl | 1))
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*tbl |= filter(*tbl) ^ bit;
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else if(filter(*tbl) == bit) {
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*++*end = *++tbl;
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*tbl = tbl[-1] | 1;
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} else
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*tbl-- = *(*end)--;
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}
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/** recover
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* recursively narrow down the search space, 4 bits of keystream at a time
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*/
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static struct Crypto1State*
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recover(uint32_t *o_head, uint32_t *o_tail, uint32_t oks,
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uint32_t *e_head, uint32_t *e_tail, uint32_t eks, int rem,
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struct Crypto1State *sl, uint32_t in)
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{
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uint32_t *o, *e, i;
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if(rem == -1) {
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for(e = e_head; e <= e_tail; ++e) {
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*e = *e << 1 ^ parity(*e & LF_POLY_EVEN) ^ !!(in & 4);
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for(o = o_head; o <= o_tail; ++o, ++sl) {
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sl->even = *o;
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sl->odd = *e ^ parity(*o & LF_POLY_ODD);
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sl[1].odd = sl[1].even = 0;
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}
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}
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return sl;
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}
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for(i = 0; i < 4 && rem--; i++) {
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oks >>= 1;
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eks >>= 1;
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in >>= 2;
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extend_table(o_head, &o_tail, oks & 1, LF_POLY_EVEN << 1 | 1,
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LF_POLY_ODD << 1, 0);
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if(o_head > o_tail)
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return sl;
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extend_table(e_head, &e_tail, eks & 1, LF_POLY_ODD,
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LF_POLY_EVEN << 1 | 1, in & 3);
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if(e_head > e_tail)
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return sl;
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}
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quicksort(o_head, o_tail);
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quicksort(e_head, e_tail);
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while(o_tail >= o_head && e_tail >= e_head)
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if(((*o_tail ^ *e_tail) >> 24) == 0) {
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o_tail = binsearch(o_head, o = o_tail);
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e_tail = binsearch(e_head, e = e_tail);
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sl = recover(o_tail--, o, oks,
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e_tail--, e, eks, rem, sl, in);
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}
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else if(*o_tail > *e_tail)
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o_tail = binsearch(o_head, o_tail) - 1;
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else
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e_tail = binsearch(e_head, e_tail) - 1;
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return sl;
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}
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/** lfsr_recovery
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* recover the state of the lfsr given 32 bits of the keystream
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* additionally you can use the in parameter to specify the value
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* that was fed into the lfsr at the time the keystream was generated
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*/
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struct Crypto1State* lfsr_recovery32(uint32_t ks2, uint32_t in)
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{
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struct Crypto1State *statelist;
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uint32_t *odd_head = 0, *odd_tail = 0, oks = 0;
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uint32_t *even_head = 0, *even_tail = 0, eks = 0;
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int i;
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for(i = 31; i >= 0; i -= 2)
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oks = oks << 1 | BEBIT(ks2, i);
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for(i = 30; i >= 0; i -= 2)
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eks = eks << 1 | BEBIT(ks2, i);
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odd_head = odd_tail = malloc(sizeof(uint32_t) << 21);
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even_head = even_tail = malloc(sizeof(uint32_t) << 21);
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statelist = malloc(sizeof(struct Crypto1State) << 18);
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if(!odd_tail-- || !even_tail-- || !statelist) {
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free(statelist);
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statelist = 0;
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goto out;
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}
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statelist->odd = statelist->even = 0;
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for(i = 1 << 20; i >= 0; --i) {
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if(filter(i) == (oks & 1))
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*++odd_tail = i;
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if(filter(i) == (eks & 1))
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*++even_tail = i;
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}
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for(i = 0; i < 4; i++) {
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extend_table_simple(odd_head, &odd_tail, (oks >>= 1) & 1);
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extend_table_simple(even_head, &even_tail, (eks >>= 1) & 1);
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}
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in = (in >> 16 & 0xff) | (in << 16) | (in & 0xff00);
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recover(odd_head, odd_tail, oks,
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even_head, even_tail, eks, 11, statelist, in << 1);
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out:
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free(odd_head);
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free(even_head);
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return statelist;
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}
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static const uint32_t S1[] = { 0x62141, 0x310A0, 0x18850, 0x0C428, 0x06214,
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0x0310A, 0x85E30, 0xC69AD, 0x634D6, 0xB5CDE, 0xDE8DA, 0x6F46D, 0xB3C83,
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0x59E41, 0xA8995, 0xD027F, 0x6813F, 0x3409F, 0x9E6FA};
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static const uint32_t S2[] = { 0x3A557B00, 0x5D2ABD80, 0x2E955EC0, 0x174AAF60,
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0x0BA557B0, 0x05D2ABD8, 0x0449DE68, 0x048464B0, 0x42423258, 0x278192A8,
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0x156042D0, 0x0AB02168, 0x43F89B30, 0x61FC4D98, 0x765EAD48, 0x7D8FDD20,
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0x7EC7EE90, 0x7F63F748, 0x79117020};
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static const uint32_t T1[] = {
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0x4F37D, 0x279BE, 0x97A6A, 0x4BD35, 0x25E9A, 0x12F4D, 0x097A6, 0x80D66,
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0xC4006, 0x62003, 0xB56B4, 0x5AB5A, 0xA9318, 0xD0F39, 0x6879C, 0xB057B,
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0x582BD, 0x2C15E, 0x160AF, 0x8F6E2, 0xC3DC4, 0xE5857, 0x72C2B, 0x39615,
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0x98DBF, 0xC806A, 0xE0680, 0x70340, 0x381A0, 0x98665, 0x4C332, 0xA272C};
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static const uint32_t T2[] = { 0x3C88B810, 0x5E445C08, 0x2982A580, 0x14C152C0,
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0x4A60A960, 0x253054B0, 0x52982A58, 0x2FEC9EA8, 0x1156C4D0, 0x08AB6268,
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0x42F53AB0, 0x217A9D58, 0x161DC528, 0x0DAE6910, 0x46D73488, 0x25CB11C0,
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0x52E588E0, 0x6972C470, 0x34B96238, 0x5CFC3A98, 0x28DE96C8, 0x12CFC0E0,
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0x4967E070, 0x64B3F038, 0x74F97398, 0x7CDC3248, 0x38CE92A0, 0x1C674950,
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0x0E33A4A8, 0x01B959D0, 0x40DCACE8, 0x26CEDDF0};
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static const uint32_t C1[] = { 0x846B5, 0x4235A, 0x211AD};
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static const uint32_t C2[] = { 0x1A822E0, 0x21A822E0, 0x21A822E0};
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/** Reverse 64 bits of keystream into possible cipher states
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* Variation mentioned in the paper. Somewhat optimized version
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*/
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struct Crypto1State* lfsr_recovery64(uint32_t ks2, uint32_t ks3)
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{
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struct Crypto1State *statelist, *sl;
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uint8_t oks[32], eks[32], hi[32];
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uint32_t low = 0, win = 0;
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uint32_t *tail, table[1 << 16];
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int i, j;
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sl = statelist = malloc(sizeof(struct Crypto1State) << 4);
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if(!sl)
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return 0;
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sl->odd = sl->even = 0;
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for(i = 30; i >= 0; i -= 2) {
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oks[i >> 1] = BEBIT(ks2, i);
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oks[16 + (i >> 1)] = BEBIT(ks3, i);
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}
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for(i = 31; i >= 0; i -= 2) {
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eks[i >> 1] = BEBIT(ks2, i);
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eks[16 + (i >> 1)] = BEBIT(ks3, i);
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}
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for(i = 0xfffff; i >= 0; --i) {
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if (filter(i) != oks[0])
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continue;
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*(tail = table) = i;
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for(j = 1; tail >= table && j < 29; ++j)
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extend_table_simple(table, &tail, oks[j]);
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if(tail < table)
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continue;
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for(j = 0; j < 19; ++j)
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low = low << 1 | parity(i & S1[j]);
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for(j = 0; j < 32; ++j)
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hi[j] = parity(i & T1[j]);
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for(; tail >= table; --tail) {
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for(j = 0; j < 3; ++j) {
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*tail = *tail << 1;
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*tail |= parity((i & C1[j]) ^ (*tail & C2[j]));
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if(filter(*tail) != oks[29 + j])
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goto continue2;
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}
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for(j = 0; j < 19; ++j)
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win = win << 1 | parity(*tail & S2[j]);
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win ^= low;
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for(j = 0; j < 32; ++j) {
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win = win << 1 ^ hi[j] ^ parity(*tail & T2[j]);
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if(filter(win) != eks[j])
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goto continue2;
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}
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*tail = *tail << 1 | parity(LF_POLY_EVEN & *tail);
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sl->odd = *tail ^ parity(LF_POLY_ODD & win);
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sl->even = win;
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++sl;
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sl->odd = sl->even = 0;
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continue2:;
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}
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}
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return statelist;
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}
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/** lfsr_rollback_bit
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* Rollback the shift register in order to get previous states
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*/
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uint8_t lfsr_rollback_bit(struct Crypto1State *s, uint32_t in, int fb)
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{
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int out;
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uint8_t ret;
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s->odd &= 0xffffff;
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s->odd ^= (s->odd ^= s->even, s->even ^= s->odd);
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out = s->even & 1;
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out ^= LF_POLY_EVEN & (s->even >>= 1);
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out ^= LF_POLY_ODD & s->odd;
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out ^= !!in;
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out ^= (ret = filter(s->odd)) & !!fb;
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s->even |= parity(out) << 23;
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return ret;
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}
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/** lfsr_rollback_byte
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* Rollback the shift register in order to get previous states
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*/
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uint8_t lfsr_rollback_byte(struct Crypto1State *s, uint32_t in, int fb)
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{
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int i, ret = 0;
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for (i = 7; i >= 0; --i)
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ret |= lfsr_rollback_bit(s, BIT(in, i), fb) << i;
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return ret;
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}
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/** lfsr_rollback_word
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* Rollback the shift register in order to get previous states
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*/
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uint32_t lfsr_rollback_word(struct Crypto1State *s, uint32_t in, int fb)
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{
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int i;
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uint32_t ret = 0;
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for (i = 31; i >= 0; --i)
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ret |= lfsr_rollback_bit(s, BEBIT(in, i), fb) << (i ^ 24);
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return ret;
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}
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/** nonce_distance
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* x,y valid tag nonces, then prng_successor(x, nonce_distance(x, y)) = y
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*/
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static uint16_t *dist = 0;
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int nonce_distance(uint32_t from, uint32_t to)
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{
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uint16_t x, i;
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if(!dist) {
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dist = malloc(2 << 16);
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if(!dist)
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return -1;
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for (x = i = 1; i; ++i) {
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dist[(x & 0xff) << 8 | x >> 8] = i;
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x = x >> 1 | (x ^ x >> 2 ^ x >> 3 ^ x >> 5) << 15;
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}
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}
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return (65535 + dist[to >> 16] - dist[from >> 16]) % 65535;
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}
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static uint32_t fastfwd[2][8] = {
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{ 0, 0x4BC53, 0xECB1, 0x450E2, 0x25E29, 0x6E27A, 0x2B298, 0x60ECB},
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{ 0, 0x1D962, 0x4BC53, 0x56531, 0xECB1, 0x135D3, 0x450E2, 0x58980}};
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/** lfsr_prefix_ks
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*
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* Is an exported helper function from the common prefix attack
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* Described in the "dark side" paper. It returns an -1 terminated array
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* of possible partial(21 bit) secret state.
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* The required keystream(ks) needs to contain the keystream that was used to
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* encrypt the NACK which is observed when varying only the 3 last bits of Nr
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* only correct iff [NR_3] ^ NR_3 does not depend on Nr_3
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*/
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uint32_t *lfsr_prefix_ks(uint8_t ks[8], int isodd)
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{
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uint32_t c, entry, *candidates = malloc(4 << 10);
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int i, size = 0, good;
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if(!candidates)
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return 0;
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for(i = 0; i < 1 << 21; ++i) {
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for(c = 0, good = 1; good && c < 8; ++c) {
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entry = i ^ fastfwd[isodd][c];
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good &= (BIT(ks[c], isodd) == filter(entry >> 1));
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good &= (BIT(ks[c], isodd + 2) == filter(entry));
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}
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if(good)
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candidates[size++] = i;
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}
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candidates[size] = -1;
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return candidates;
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}
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/** check_pfx_parity
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* helper function which eliminates possible secret states using parity bits
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*/
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static struct Crypto1State*
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check_pfx_parity(uint32_t prefix, uint32_t rresp, uint8_t parities[8][8],
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uint32_t odd, uint32_t even, struct Crypto1State* sl)
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{
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uint32_t ks1, nr, ks2, rr, ks3, c, good = 1;
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for(c = 0; good && c < 8; ++c) {
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sl->odd = odd ^ fastfwd[1][c];
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sl->even = even ^ fastfwd[0][c];
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lfsr_rollback_bit(sl, 0, 0);
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lfsr_rollback_bit(sl, 0, 0);
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ks3 = lfsr_rollback_bit(sl, 0, 0);
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ks2 = lfsr_rollback_word(sl, 0, 0);
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ks1 = lfsr_rollback_word(sl, prefix | c << 5, 1);
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nr = ks1 ^ (prefix | c << 5);
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rr = ks2 ^ rresp;
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good &= parity(nr & 0x000000ff) ^ parities[c][3] ^ BIT(ks2, 24);
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good &= parity(rr & 0xff000000) ^ parities[c][4] ^ BIT(ks2, 16);
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good &= parity(rr & 0x00ff0000) ^ parities[c][5] ^ BIT(ks2, 8);
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good &= parity(rr & 0x0000ff00) ^ parities[c][6] ^ BIT(ks2, 0);
|
|
good &= parity(rr & 0x000000ff) ^ parities[c][7] ^ ks3;
|
|
}
|
|
|
|
return sl + good;
|
|
}
|
|
|
|
|
|
/** lfsr_common_prefix
|
|
* Implentation of the common prefix attack.
|
|
*/
|
|
struct Crypto1State*
|
|
lfsr_common_prefix(uint32_t pfx, uint32_t rr, uint8_t ks[8], uint8_t par[8][8])
|
|
{
|
|
struct Crypto1State *statelist, *s;
|
|
uint32_t *odd, *even, *o, *e, top;
|
|
|
|
odd = lfsr_prefix_ks(ks, 1);
|
|
even = lfsr_prefix_ks(ks, 0);
|
|
|
|
s = statelist = malloc((sizeof *statelist) << 20);
|
|
if(!s || !odd || !even) {
|
|
free(statelist);
|
|
statelist = 0;
|
|
goto out;
|
|
}
|
|
|
|
for(o = odd; *o + 1; ++o)
|
|
for(e = even; *e + 1; ++e)
|
|
for(top = 0; top < 64; ++top) {
|
|
*o += 1 << 21;
|
|
*e += (!(top & 7) + 1) << 21;
|
|
s = check_pfx_parity(pfx, rr, par, *o, *e, s);
|
|
}
|
|
|
|
s->odd = s->even = 0;
|
|
out:
|
|
free(odd);
|
|
free(even);
|
|
return statelist;
|
|
}
|