+
+// 32 bit recover key from 2 nonces
+uint64_t mfkey32(uint32_t uid, uint32_t nt, uint32_t nr0_enc, uint32_t ar0_enc, uint32_t nr1_enc, uint32_t ar1_enc) {
+ struct Crypto1State *s,*t;
+ uint64_t key=0; // recovered key
+ /*uint32_t uid; // serial number
+ uint32_t nt; // tag challenge
+ uint32_t nr0_enc; // first encrypted reader challenge
+ uint32_t ar0_enc; // first encrypted reader response
+ uint32_t nr1_enc; // second encrypted reader challenge
+ uint32_t ar1_enc; // second encrypted reader response
+ */
+ uint8_t found=0;
+ //uint32_t ks2; // keystream used to encrypt reader response
+
+ // Generate lfsr succesors of the tag challenge
+ prng_successor(nt, 64);
+ prng_successor(nt, 96);
+
+ // Extract the keystream from the messages
+ //ks2 = ar0_enc ^ prng_successor(nt, 64);
+
+ s = lfsr_recovery32(ar0_enc ^ prng_successor(nt, 64), 0);
+
+ for(t = s; t->odd | t->even; ++t) {
+ lfsr_rollback_word(t, 0, 0);
+ lfsr_rollback_word(t, nr0_enc, 1);
+ lfsr_rollback_word(t, uid ^ nt, 0);
+ crypto1_get_lfsr(t, &key);
+ crypto1_word(t, uid ^ nt, 0);
+ crypto1_word(t, nr1_enc, 1);
+ if (ar1_enc == (crypto1_word(t, 0, 0) ^ prng_successor(nt, 64))) {
+ //printf("\nFound Key: [%012"llx"]\n\n",key);
+ found = 1;
+ break;
+ }
+ }
+ free(s);
+
+ if (found) return key;
+ return 0;
+}