X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/b69adb794594cc7ea43d3aa70aab091265195abf..207fc33a4252560197931244b1e888d5cc3994c7:/armsrc/crapto1.c?ds=sidebyside diff --git a/armsrc/crapto1.c b/armsrc/crapto1.c index 2fdeb924..e2058651 100644 --- a/armsrc/crapto1.c +++ b/armsrc/crapto1.c @@ -15,7 +15,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, US$ - Copyright (C) 2008-2008 bla + Copyright (C) 2008-2014 bla */ #include "crapto1.h" #include @@ -24,17 +24,16 @@ static uint8_t filterlut[1 << 20]; static void __attribute__((constructor)) fill_lut() { - uint32_t i; - for(i = 0; i < 1 << 20; ++i) - filterlut[i] = filter(i); + uint32_t i; + for(i = 0; i < 1 << 20; ++i) + filterlut[i] = filter(i); } #define filter(x) (filterlut[(x) & 0xfffff]) #endif static void quicksort(uint32_t* const start, uint32_t* const stop) { - uint32_t *it = start + 1, *rit = stop; - uint32_t tmp; + uint32_t *it = start + 1, *rit = stop, t; if(it > rit) return; @@ -44,19 +43,13 @@ static void quicksort(uint32_t* const start, uint32_t* const stop) ++it; else if(*rit > *start) --rit; - else { - tmp = *it; - *it = *rit; - *rit = tmp; - } + else + t = *it, *it = *rit, *rit = t; if(*rit >= *start) --rit; - if(rit != start) { - tmp = *rit; - *rit = *start; - *start = tmp; - } + if(rit != start) + t = *rit, *rit = *start, *start = t; quicksort(start, rit - 1); quicksort(rit + 1, stop); @@ -191,6 +184,7 @@ struct Crypto1State* lfsr_recovery32(uint32_t ks2, uint32_t in) 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) @@ -207,6 +201,7 @@ struct Crypto1State* lfsr_recovery32(uint32_t ks2, uint32_t in) 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; @@ -214,11 +209,15 @@ struct Crypto1State* lfsr_recovery32(uint32_t ks2, uint32_t in) *++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); recover(odd_head, odd_tail, oks, even_head, even_tail, eks, 11, statelist, in << 1); @@ -326,12 +325,10 @@ uint8_t lfsr_rollback_bit(struct Crypto1State *s, uint32_t in, int fb) { int out; uint8_t ret; - uint32_t tmp; + 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); @@ -347,9 +344,21 @@ uint8_t lfsr_rollback_bit(struct Crypto1State *s, uint32_t in, int fb) */ uint8_t lfsr_rollback_byte(struct Crypto1State *s, uint32_t in, int fb) { + /* int i, ret = 0; for (i = 7; i >= 0; --i) ret |= lfsr_rollback_bit(s, BIT(in, i), fb) << i; +*/ +// unfold loop 20160112 + uint8_t ret = 0; + ret |= lfsr_rollback_bit(s, BIT(in, 7), fb) << 7; + ret |= lfsr_rollback_bit(s, BIT(in, 6), fb) << 6; + ret |= lfsr_rollback_bit(s, BIT(in, 5), fb) << 5; + ret |= lfsr_rollback_bit(s, BIT(in, 4), fb) << 4; + ret |= lfsr_rollback_bit(s, BIT(in, 3), fb) << 3; + ret |= lfsr_rollback_bit(s, BIT(in, 2), fb) << 2; + ret |= lfsr_rollback_bit(s, BIT(in, 1), fb) << 1; + ret |= lfsr_rollback_bit(s, BIT(in, 0), fb) << 0; return ret; } /** lfsr_rollback_word @@ -357,10 +366,49 @@ uint8_t lfsr_rollback_byte(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) ret |= lfsr_rollback_bit(s, BEBIT(in, i), fb) << (i ^ 24); +*/ +// unfold loop 20160112 + uint32_t ret = 0; + ret |= lfsr_rollback_bit(s, BEBIT(in, 31), fb) << (31 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 30), fb) << (30 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 29), fb) << (29 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 28), fb) << (28 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 27), fb) << (27 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 26), fb) << (26 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 25), fb) << (25 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 24), fb) << (24 ^ 24); + + ret |= lfsr_rollback_bit(s, BEBIT(in, 23), fb) << (23 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 22), fb) << (22 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 21), fb) << (21 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 20), fb) << (20 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 19), fb) << (19 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 18), fb) << (18 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 17), fb) << (17 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 16), fb) << (16 ^ 24); + + ret |= lfsr_rollback_bit(s, BEBIT(in, 15), fb) << (15 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 14), fb) << (14 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 13), fb) << (13 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 12), fb) << (12 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 11), fb) << (11 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 10), fb) << (10 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 9), fb) << (9 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 8), fb) << (8 ^ 24); + + ret |= lfsr_rollback_bit(s, BEBIT(in, 7), fb) << (7 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 6), fb) << (6 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 5), fb) << (5 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 4), fb) << (4 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 3), fb) << (3 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 2), fb) << (2 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 1), fb) << (1 ^ 24); + ret |= lfsr_rollback_bit(s, BEBIT(in, 0), fb) << (0 ^ 24); return ret; } @@ -371,10 +419,11 @@ static uint16_t *dist = 0; int nonce_distance(uint32_t from, uint32_t to) { uint16_t x, i; - if(!dist) { + // generate distance lookup table + if (!dist) { dist = malloc(2 << 16); - if(!dist) - return -1; + if (!dist) return -1; + for (x = i = 1; i; ++i) { dist[(x & 0xff) << 8 | x >> 8] = i; x = x >> 1 | (x ^ x >> 2 ^ x >> 3 ^ x >> 5) << 15; @@ -387,6 +436,8 @@ int nonce_distance(uint32_t from, uint32_t to) 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 @@ -396,13 +447,13 @@ static uint32_t fastfwd[2][8] = { * 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* lfsr_prefix_ks(uint8_t ks[8], int isodd) { - uint32_t c, entry, *candidates = malloc(4 << 10); - int i, size = 0, good; - - if(!candidates) - return 0; + uint32_t *candidates = malloc(4 << 10); + if(!candidates) return 0; + + uint32_t c, entry; + int size = 0, i, good; for(i = 0; i < 1 << 21; ++i) { for(c = 0, good = 1; good && c < 8; ++c) { @@ -422,9 +473,7 @@ uint32_t *lfsr_prefix_ks(uint8_t ks[8], int isodd) /** check_pfx_parity * helper function which eliminates possible secret states using parity bits */ -static struct Crypto1State* -check_pfx_parity(uint32_t prefix, uint32_t rresp, uint8_t parities[8][8], - uint32_t odd, uint32_t even, struct Crypto1State* sl) +static struct Crypto1State* check_pfx_parity(uint32_t prefix, uint32_t rresp, uint8_t parities[8][8], uint32_t odd, uint32_t even, struct Crypto1State* sl) { uint32_t ks1, nr, ks2, rr, ks3, c, good = 1; @@ -452,12 +501,16 @@ check_pfx_parity(uint32_t prefix, uint32_t rresp, uint8_t parities[8][8], 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]) +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; @@ -465,11 +518,11 @@ 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); - s = statelist = malloc((sizeof *statelist) << 20); + s = statelist = malloc((sizeof *statelist) << 21); if(!s || !odd || !even) { free(statelist); statelist = 0; - goto out; + goto out; } for(o = odd; *o + 1; ++o) @@ -485,4 +538,4 @@ out: free(odd); free(even); return statelist; -} +} \ No newline at end of file