Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, US$
- Copyright (C) 2008-2008 bla <blapost@gmail.com>
+ Copyright (C) 2008-2014 bla <blapost@gmail.com>
*/
#include "crapto1.h"
#include <stdlib.h>
-#include <stdbool.h>
#if !defined LOWMEM && defined __GNUC__
static uint8_t filterlut[1 << 20];
bucket_info->numbuckets = nonempty_bucket;
}
}
-
/** binsearch
* Binary search for the first occurence of *stop's MSB in sorted [start,stop]
*/
-static inline uint32_t*
-binsearch(uint32_t *start, uint32_t *stop)
+static inline uint32_t* binsearch(uint32_t *start, uint32_t *stop)
{
uint32_t mid, val = *stop & 0xff000000;
while(start != stop)
extend_table(uint32_t *tbl, uint32_t **end, int bit, int m1, int m2, uint32_t in)
{
in <<= 24;
-
- for(uint32_t *p = tbl; p <= *end; p++) {
- *p <<= 1;
- if(filter(*p) != filter(*p | 1)) { // replace
- *p |= filter(*p) ^ bit;
- update_contribution(p, m1, m2);
- *p ^= in;
- } else if(filter(*p) == bit) { // insert
- *++*end = p[1];
- p[1] = p[0] | 1;
- update_contribution(p, m1, m2);
- *p++ ^= in;
- update_contribution(p, m1, m2);
- *p ^= in;
- } else { // drop
- *p-- = *(*end)--;
- }
- }
-
+ for(*tbl <<= 1; tbl <= *end; *++tbl <<= 1)
+ if(filter(*tbl) ^ filter(*tbl | 1)) {
+ *tbl |= filter(*tbl) ^ bit;
+ update_contribution(tbl, m1, m2);
+ *tbl ^= in;
+ } else if(filter(*tbl) == bit) {
+ *++*end = tbl[1];
+ tbl[1] = tbl[0] | 1;
+ update_contribution(tbl, m1, m2);
+ *tbl++ ^= in;
+ update_contribution(tbl, m1, m2);
+ *tbl ^= in;
+ } else
+ *tbl-- = *(*end)--;
}
-
-
/** extend_table_simple
* using a bit of the keystream extend the table of possible lfsr states
*/
-static inline void
-extend_table_simple(uint32_t *tbl, uint32_t **end, int bit)
+static inline void extend_table_simple(uint32_t *tbl, uint32_t **end, int bit)
{
for(*tbl <<= 1; tbl <= *end; *++tbl <<= 1)
- if(filter(*tbl) ^ filter(*tbl | 1)) { // replace
+ if(filter(*tbl) ^ filter(*tbl | 1))
*tbl |= filter(*tbl) ^ bit;
- } else if(filter(*tbl) == bit) { // insert
+ else if(filter(*tbl) == bit) {
*++*end = *++tbl;
*tbl = tbl[-1] | 1;
- } else // drop
+
+ } else
*tbl-- = *(*end)--;
}
uint32_t *e_head, uint32_t *e_tail, uint32_t eks, int rem,
struct Crypto1State *sl, uint32_t in, bucket_array_t bucket)
{
- uint32_t *o, *e;
+ uint32_t *o, *e, i;
bucket_info_t bucket_info;
if(rem == -1) {
for(o = o_head; o <= o_tail; ++o, ++sl) {
sl->even = *o;
sl->odd = *e ^ parity(*o & LF_POLY_ODD);
+ sl[1].odd = sl[1].even = 0;
}
}
- sl->odd = sl->even = 0;
return sl;
}
- for(uint32_t i = 0; i < 4 && rem--; i++) {
- extend_table(o_head, &o_tail, (oks >>= 1) & 1,
- LF_POLY_EVEN << 1 | 1, LF_POLY_ODD << 1, 0);
+ for(i = 0; i < 4 && rem--; i++) {
+ oks >>= 1;
+ eks >>= 1;
+ in >>= 2;
+ extend_table(o_head, &o_tail, oks & 1, LF_POLY_EVEN << 1 | 1,
+ LF_POLY_ODD << 1, 0);
if(o_head > o_tail)
return sl;
- extend_table(e_head, &e_tail, (eks >>= 1) & 1,
- LF_POLY_ODD, LF_POLY_EVEN << 1 | 1, (in >>= 2) & 3);
+ extend_table(e_head, &e_tail, eks & 1, LF_POLY_ODD,
+ LF_POLY_EVEN << 1 | 1, in & 3);
if(e_head > e_tail)
return sl;
}
-
bucket_sort_intersect(e_head, e_tail, o_head, o_tail, &bucket_info, bucket);
for (int i = bucket_info.numbuckets - 1; i >= 0; i--) {
uint32_t *even_head = 0, *even_tail = 0, eks = 0;
int i;
- // split the keystream into an odd and even part
for(i = 31; i >= 0; i -= 2)
oks = oks << 1 | BEBIT(ks2, i);
for(i = 30; i >= 0; i -= 2)
even_head = even_tail = malloc(sizeof(uint32_t) << 21);
statelist = malloc(sizeof(struct Crypto1State) << 18);
if(!odd_tail-- || !even_tail-- || !statelist) {
+ free(statelist);
+ statelist = 0;
goto out;
}
statelist->odd = statelist->even = 0;
}
- // initialize statelists: add all possible states which would result into the rightmost 2 bits of the keystream
for(i = 1 << 20; i >= 0; --i) {
if(filter(i) == (oks & 1))
*++odd_tail = i;
*++even_tail = i;
}
- // extend the statelists. Look at the next 8 Bits of the keystream (4 Bit each odd and even):
for(i = 0; i < 4; i++) {
extend_table_simple(odd_head, &odd_tail, (oks >>= 1) & 1);
extend_table_simple(even_head, &even_tail, (eks >>= 1) & 1);
}
- // the statelists now contain all states which could have generated the last 10 Bits of the keystream.
- // 22 bits to go to recover 32 bits in total. From now on, we need to take the "in"
- // parameter into account.
-
- in = (in >> 16 & 0xff) | (in << 16) | (in & 0xff00); // Byte swapping
-
+ in = (in >> 16 & 0xff) | (in << 16) | (in & 0xff00);
recover(odd_head, odd_tail, oks,
even_head, even_tail, eks, 11, statelist, in << 1, bucket);
-
out:
free(odd_head);
free(even_head);
sl->odd = sl->even = 0;
for(i = 30; i >= 0; i -= 2) {
- oks[i >> 1] = BIT(ks2, i ^ 24);
- oks[16 + (i >> 1)] = BIT(ks3, i ^ 24);
+ oks[i >> 1] = BEBIT(ks2, i);
+ oks[16 + (i >> 1)] = BEBIT(ks3, i);
}
for(i = 31; i >= 0; i -= 2) {
- eks[i >> 1] = BIT(ks2, i ^ 24);
- eks[16 + (i >> 1)] = BIT(ks3, i ^ 24);
+ eks[i >> 1] = BEBIT(ks2, i);
+ eks[16 + (i >> 1)] = BEBIT(ks3, i);
}
for(i = 0xfffff; i >= 0; --i) {
/** lfsr_rollback_bit
* Rollback the shift register in order to get previous states
*/
-void lfsr_rollback_bit(struct Crypto1State *s, uint32_t in, int fb)
+uint8_t lfsr_rollback_bit(struct Crypto1State *s, uint32_t in, int fb)
{
int out;
- uint32_t tmp;
-
+ uint8_t ret;
+ uint32_t t;
+
s->odd &= 0xffffff;
- tmp = s->odd;
- s->odd = s->even;
- s->even = tmp;
+ t = s->odd, s->odd = s->even, s->even = t;
out = s->even & 1;
out ^= LF_POLY_EVEN & (s->even >>= 1);
out ^= LF_POLY_ODD & s->odd;
out ^= !!in;
- out ^= filter(s->odd) & !!fb;
+ out ^= (ret = filter(s->odd)) & !!fb;
s->even |= parity(out) << 23;
+ return ret;
}
/** lfsr_rollback_byte
* Rollback the shift register in order to get previous states
*/
-void lfsr_rollback_byte(struct Crypto1State *s, uint32_t in, int fb)
+uint8_t lfsr_rollback_byte(struct Crypto1State *s, uint32_t in, int fb)
{
- int i;
+ int i, ret=0;
for (i = 7; i >= 0; --i)
- lfsr_rollback_bit(s, BEBIT(in, i), fb);
+ ret |= lfsr_rollback_bit(s, BIT(in, i), fb) << i;
+ return ret;
}
/** lfsr_rollback_word
* Rollback the shift register in order to get previous states
*/
-void lfsr_rollback_word(struct Crypto1State *s, uint32_t in, int fb)
+uint32_t lfsr_rollback_word(struct Crypto1State *s, uint32_t in, int fb)
{
int i;
+ uint32_t ret = 0;
for (i = 31; i >= 0; --i)
- lfsr_rollback_bit(s, BEBIT(in, i), fb);
+ ret |= lfsr_rollback_bit(s, BEBIT(in, i), fb) << (i ^ 24);
+ return ret;
}
/** nonce_distance
static uint32_t fastfwd[2][8] = {
{ 0, 0x4BC53, 0xECB1, 0x450E2, 0x25E29, 0x6E27A, 0x2B298, 0x60ECB},
{ 0, 0x1D962, 0x4BC53, 0x56531, 0xECB1, 0x135D3, 0x450E2, 0x58980}};
-
-
/** lfsr_prefix_ks
*
* Is an exported helper function from the common prefix attack
* Described in the "dark side" paper. It returns an -1 terminated array
* of possible partial(21 bit) secret state.
* The required keystream(ks) needs to contain the keystream that was used to
- * encrypt the NACK which is observed when varying only the 4 last bits of Nr
+ * encrypt the NACK which is observed when varying only the 3 last bits of Nr
* only correct iff [NR_3] ^ NR_3 does not depend on Nr_3
*/
uint32_t *lfsr_prefix_ks(uint8_t ks[8], int isodd)
{
- uint32_t *candidates = malloc(4 << 21);
- uint32_t c, entry;
- int size, i;
-
+ uint32_t c, entry, *candidates = malloc(4 << 10);
+ int i, size = 0, good;
+
if(!candidates)
return 0;
- size = (1 << 21) - 1;
- for(i = 0; i <= size; ++i)
- candidates[i] = i;
-
- for(c = 0; c < 8; ++c)
- for(i = 0;i <= size; ++i) {
- entry = candidates[i] ^ fastfwd[isodd][c];
-
- if(filter(entry >> 1) == BIT(ks[c], isodd))
- if(filter(entry) == BIT(ks[c], isodd + 2))
- continue;
-
- candidates[i--] = candidates[size--];
+ for(i = 0; i < 1 << 21; ++i) {
+ for(c = 0, good = 1; good && c < 8; ++c) {
+ entry = i ^ fastfwd[isodd][c];
+ good &= (BIT(ks[c], isodd) == filter(entry >> 1));
+ good &= (BIT(ks[c], isodd + 2) == filter(entry));
}
-
- candidates[size + 1] = -1;
+ if(good)
+ candidates[size++] = i;
+ }
+
+ candidates[size] = -1;
return candidates;
}
-/** brute_top
+/** check_pfx_parity
* helper function which eliminates possible secret states using parity bits
*/
static struct Crypto1State*
-brute_top(uint32_t prefix, uint32_t rresp, unsigned char parities[8][8],
- uint32_t odd, uint32_t even, struct Crypto1State* sl)
+check_pfx_parity(uint32_t prefix, uint32_t rresp, uint8_t parities[8][8],
+ uint32_t odd, uint32_t even, struct Crypto1State* sl)
{
- struct Crypto1State s;
- uint32_t ks1, nr, ks2, rr, ks3, good, c;
+ uint32_t ks1, nr, ks2, rr, ks3, c, good = 1, no_par = 1;
- bool no_par = true;
for (int i = 0; i < 8; i++) {
for (int j = 0; j < 8; j++) {
if (parities[i][j] != 0) {
- no_par = false;
+ no_par = 0;
break;
}
}
}
- for(c = 0; c < 8; ++c) {
- s.odd = odd ^ fastfwd[1][c];
- s.even = even ^ fastfwd[0][c];
+ for(c = 0; good && c < 8; ++c) {
+ sl->odd = odd ^ fastfwd[1][c];
+ sl->even = even ^ fastfwd[0][c];
- lfsr_rollback_bit(&s, 0, 0);
- lfsr_rollback_bit(&s, 0, 0);
- lfsr_rollback_bit(&s, 0, 0);
+ lfsr_rollback_bit(sl, 0, 0);
+ lfsr_rollback_bit(sl, 0, 0);
- lfsr_rollback_word(&s, 0, 0);
- lfsr_rollback_word(&s, prefix | c << 5, 1);
-
- sl->odd = s.odd;
- sl->even = s.even;
+ ks3 = lfsr_rollback_bit(sl, 0, 0);
+ ks2 = lfsr_rollback_word(sl, 0, 0);
+ ks1 = lfsr_rollback_word(sl, prefix | c << 5, 1);
if (no_par)
break;
- ks1 = crypto1_word(&s, prefix | c << 5, 1);
- ks2 = crypto1_word(&s,0,0);
- ks3 = crypto1_word(&s, 0,0);
nr = ks1 ^ (prefix | c << 5);
rr = ks2 ^ rresp;
- good = 1;
good &= parity(nr & 0x000000ff) ^ parities[c][3] ^ BIT(ks2, 24);
good &= parity(rr & 0xff000000) ^ parities[c][4] ^ BIT(ks2, 16);
good &= parity(rr & 0x00ff0000) ^ parities[c][5] ^ BIT(ks2, 8);
good &= parity(rr & 0x0000ff00) ^ parities[c][6] ^ BIT(ks2, 0);
- good &= parity(rr & 0x000000ff) ^ parities[c][7] ^ BIT(ks3, 24);
-
- if(!good)
- return sl;
+ good &= parity(rr & 0x000000ff) ^ parities[c][7] ^ ks3;
}
- return ++sl;
+ return sl + good;
}
/** lfsr_common_prefix
* Implentation of the common prefix attack.
- * Requires the 28 bit constant prefix used as reader nonce (pfx)
- * The reader response used (rr)
- * The keystream used to encrypt the observed NACK's (ks)
- * The parity bits (par)
- * It returns a zero terminated list of possible cipher states after the
- * tag nonce was fed in
*/
struct Crypto1State*
lfsr_common_prefix(uint32_t pfx, uint32_t rr, uint8_t ks[8], uint8_t par[8][8])
odd = lfsr_prefix_ks(ks, 1);
even = lfsr_prefix_ks(ks, 0);
- statelist = malloc((sizeof *statelist) << 21); //how large should be?
- if(!statelist || !odd || !even)
- {
- free(statelist);
- free(odd);
- free(even);
- return 0;
+ s = statelist = malloc((sizeof *statelist) << 20);
+ if(!s || !odd || !even) {
+ free(statelist);
+ statelist = 0;
+ goto out;
}
- s = statelist;
- for(o = odd; *o != -1; ++o)
- for(e = even; *e != -1; ++e)
+ for(o = odd; *o + 1; ++o)
+ for(e = even; *e + 1; ++e)
for(top = 0; top < 64; ++top) {
- *o = (*o & 0x1fffff) | (top << 21);
- *e = (*e & 0x1fffff) | (top >> 3) << 21;
- s = brute_top(pfx, rr, par, *o, *e, s);
+ *o += 1 << 21;
+ *e += (!(top & 7) + 1) << 21;
+ s = check_pfx_parity(pfx, rr, par, *o, *e, s);
}
- s->odd = s->even = -1;
- //printf("state count = %d\n",s-statelist);
-
+ s->odd = s->even = 0;
+out:
free(odd);
free(even);
-
return statelist;
}
projects / proxmark3-svn / commitdiff