// Generate lfsr succesors of the tag challenge
printf("\nLFSR succesors of the tag challenge:\n");
- printf(" nt': %08x\n",prng_successor(nt0, 64));
- printf(" nt'': %08x\n",prng_successor(nt0, 96));
+ uint32_t p64 = prng_successor(nt0, 64);
+ uint32_t p64b = prng_successor(nt1, 64);
+
+ printf(" nt': %08x\n", p64);
+ printf(" nt'': %08x\n", prng_successor(p64, 32));
clock_t t1 = clock();
// Extract the keystream from the messages
printf("\nKeystream used to generate {ar} and {at}:\n");
- ks2 = ar0_enc ^ prng_successor(nt0, 64);
+ ks2 = ar0_enc ^ p64;
printf(" ks2: %08x\n",ks2);
- s = lfsr_recovery32(ar0_enc ^ prng_successor(nt0, 64), 0);
+ s = lfsr_recovery32(ar0_enc ^ p64, 0);
+
for(t = s; t->odd | t->even; ++t) {
lfsr_rollback_word(t, 0, 0);
crypto1_word(t, uid ^ nt1, 0);
crypto1_word(t, nr1_enc, 1);
- if (ar1_enc == (crypto1_word(t, 0, 0) ^ prng_successor(nt1, 64))) {
+ if (ar1_enc == (crypto1_word(t, 0, 0) ^ p64b)) {
printf("\nFound Key: [%012"llx"]\n\n",key);
break;}
}