CHG: 'LF VISA2000' adding askedgedetection when decoding allows for some traces to...

[proxmark3-svn] / client / nonce2key / nonce2key.c

diff --git a/client/nonce2key/nonce2key.c b/client/nonce2key/nonce2key.c
index 95c4cf5f113931db3db30be288e1f94e7ef539ff..3d3d1e374976cc2cd159633a8bf43a8534ca4900 100644 (file)
--- a/client/nonce2key/nonce2key.c
+++ b/client/nonce2key/nonce2key.c
@@ -54,15 +54,19 @@ int nonce2key(uint32_t uid, uint32_t nt, uint32_t nr, uint64_t par_info, uint64_
        return 0;
 }
 
+int compar_intA(const void * a, const void * b) {
+       if (*(int64_t*)b == *(int64_t*)a) return 0;
+       if (*(int64_t*)b > *(int64_t*)a) return 1;
+       return -1;
+}
+
 // call when PAR == 0,  special attack?  It seems to need two calls.  with same uid, block, keytype
 int nonce2key_ex(uint8_t blockno, uint8_t keytype, uint32_t uid, uint32_t nt, uint32_t nr, uint64_t ks_info, uint64_t * key) {
 
        struct Crypto1State *state;
        uint32_t i, pos, key_count;
-       byte_t ks3x[8];
-
+       uint8_t ks3x[8];
        uint64_t key_recovered;
-
        int64_t *state_s;
        static uint8_t last_blockno;
        static uint8_t last_keytype;
@@ -83,58 +87,70 @@ int nonce2key_ex(uint8_t blockno, uint8_t keytype, uint32_t uid, uint32_t nt, ui
 
        // Reset the last three significant bits of the reader nonce
        nr &= 0xffffff1f;
-
-       PrintAndLog("uid(%08x) nt(%08x) ks(%016"llx") nr(%08x)\n", uid, nt, ks_info, nr);
  
+       // split keystream into array
        for (pos=0; pos<8; pos++) {
                ks3x[7-pos] = (ks_info >> (pos*8)) & 0x0f;
        }
-  
-       PrintAndLog("parity is all zero, try special attack. Just wait for few more seconds...");
-       
+ 
+       // find possible states for this keystream
        state = lfsr_common_prefix_ex(nr, ks3x);
+
+       if (!state) {
+               PrintAndLog("Failed getting states");
+               return 1;
+       }
+       
        state_s = (int64_t*)state;
        
+       uint32_t xored = uid ^ nt;
+       
        for (i = 0; (state) && ((state + i)->odd != -1); i++) {
-               lfsr_rollback_word(state + i, uid ^ nt, 0);
+               lfsr_rollback_word(state + i, xored, 0);
                crypto1_get_lfsr(state + i, &key_recovered);
                *(state_s + i) = key_recovered;
        }
-       
-       if(!state)
-               return 1;
-       
-       qsort(state_s, i, sizeof(*state_s), compar_int);
+
+       qsort(state_s, i, sizeof(int64_t), compar_intA);
        *(state_s + i) = -1;
        
-       //Create the intersection:
-       if ( last_keylist != NULL) {
+       // first call to this function.  clear all other stuff and set new found states.
+       if (last_keylist == NULL) {
+               free(last_keylist);
+               last_keylist = state_s;
+               PrintAndLog("parity is all zero, testing special attack. First call, this attack needs at least two calls. Hold on...");                
+               PrintAndLog("uid(%08x) nt(%08x) ks(%016"llx") nr(%08x)\n", uid, nt, ks_info, nr);
+               return 1;
+       }
 
-               int64_t *p1, *p2, *p3;
-               p1 = p3 = last_keylist; 
-               p2 = state_s;
+       PrintAndLog("uid(%08x) nt(%08x) ks(%016"llx") nr(%08x)\n", uid, nt, ks_info, nr);
+               
+       //Create the intersection:
+       int64_t *p1, *p2, *p3;
+       p1 = p3 = last_keylist; 
+       p2 = state_s;
                
-               while ( *p1 != -1 && *p2 != -1 ) {
-                       if (compar_int(p1, p2) == 0) {
-                               printf("p1:%"llx" p2:%"llx" p3:%"llx" key:%012"llx"\n",(uint64_t)(p1-last_keylist),(uint64_t)(p2-state_s),(uint64_t)(p3-last_keylist),*p1);
-                               *p3++ = *p1++;
-                               p2++;
-                       }
-                       else {
-                               while (compar_int(p1, p2) == -1) ++p1;
-                               while (compar_int(p1, p2) == 1) ++p2;
-                       }
+       while ( *p1 != -1 && *p2 != -1 ) {
+               if (compar_intA(p1, p2) == 0) {
+                       printf("p1:%"llx" p2:%"llx" p3:%"llx" key:%012"llx"\n",(uint64_t)(p1-last_keylist),(uint64_t)(p2-state_s),(uint64_t)(p3-last_keylist),*p1);
+                       *p3++ = *p1++;
+                       p2++;
+               }
+               else {
+                       while (compar_intA(p1, p2) == -1) ++p1;
+                       while (compar_intA(p1, p2) == 1) ++p2;
                }
-               key_count = p3 - last_keylist;
-               PrintAndLog("one A");
-       } else {
-               key_count = 0;
-               PrintAndLog("one B");
        }
-
-       printf("key_count:%d\n", key_count);
+       key_count = p3 - last_keylist;
+       printf("key_count: %d\n", key_count);
+       if ( key_count == 0 ){
+               free(state);
+               state = NULL;
+               return 0;
+       }
        
-       // The list may still contain several key candidates. Test each of them with mfCheckKeys
+       uint8_t retval = 1;
+       // Validate all key candidates with testing each of them with mfCheckKeys
        uint8_t keyBlock[6] = {0,0,0,0,0,0};
        uint64_t key64;
        for (i = 0; i < key_count; i++) {
@@ -143,16 +159,17 @@ int nonce2key_ex(uint8_t blockno, uint8_t keytype, uint32_t uid, uint32_t nt, ui
                key64 = 0;
                if (!mfCheckKeys(blockno, keytype, false, 1, keyBlock, &key64)) {
                        *key = key64;
-                       free(last_keylist);
-                       last_keylist = NULL;
-                       free(state);
-                       return 0;
+                       retval = 0;
+                       goto out;
                }
-       }       
+       }
        
+out:
        free(last_keylist);
-       last_keylist = state_s;
-       return 1;
+       last_keylist = NULL;
+       free(state);
+       state = NULL;
+       return retval;
 }
 
 // 32 bit recover key from 2 nonces