Merge branch 'master' of https://github.com/iceman1001/proxmark3

[proxmark3-svn] / armsrc / iso14443a.c

diff --git a/armsrc/iso14443a.c b/armsrc/iso14443a.c
index 570f028cb4f5cea47b1bc581e76216b275fdbdc3..4bd55fb3b75d77681120a6d4c4b3150731aa63c6 100644 (file)
--- a/armsrc/iso14443a.c
+++ b/armsrc/iso14443a.c
@@ -2145,29 +2145,24 @@ int32_t dist_nt(uint32_t nt1, uint32_t nt2) {
        uint32_t nttmp1 = nt1;
        uint32_t nttmp2 = nt2;
 
-       for (uint16_t i = 1; i < 32768/8; ++i) {
+       // 0xFFFF -- Half up and half down to find distance between nonces
+       for (uint16_t i = 1; i < 32768/8; i += 8) {
                nttmp1 = prng_successor(nttmp1, 1);     if (nttmp1 == nt2) return i;
-               nttmp2 = prng_successor(nttmp2, 1);     if (nttmp2 == nt1) return -i;
-               
                nttmp1 = prng_successor(nttmp1, 1);     if (nttmp1 == nt2) return i+1;
-               nttmp2 = prng_successor(nttmp2, 1);     if (nttmp2 == nt1) return -(i+1);
-               
                nttmp1 = prng_successor(nttmp1, 1);     if (nttmp1 == nt2) return i+2;
-               nttmp2 = prng_successor(nttmp2, 1);     if (nttmp2 == nt1) return -(i+2);
-
                nttmp1 = prng_successor(nttmp1, 1);     if (nttmp1 == nt2) return i+3;
-               nttmp2 = prng_successor(nttmp2, 1);     if (nttmp2 == nt1) return -(i+3);
-               
                nttmp1 = prng_successor(nttmp1, 1);     if (nttmp1 == nt2) return i+4;
-               nttmp2 = prng_successor(nttmp2, 1);     if (nttmp2 == nt1) return -(i+4);
-               
                nttmp1 = prng_successor(nttmp1, 1);     if (nttmp1 == nt2) return i+5;
-               nttmp2 = prng_successor(nttmp2, 1);     if (nttmp2 == nt1) return -(i+5);
-               
                nttmp1 = prng_successor(nttmp1, 1);     if (nttmp1 == nt2) return i+6;
-               nttmp2 = prng_successor(nttmp2, 1);     if (nttmp2 == nt1) return -(i+6);
-               
                nttmp1 = prng_successor(nttmp1, 1);     if (nttmp1 == nt2) return i+7;
+               
+               nttmp2 = prng_successor(nttmp2, 1);     if (nttmp2 == nt1) return -i;
+               nttmp2 = prng_successor(nttmp2, 1);     if (nttmp2 == nt1) return -(i+1);
+               nttmp2 = prng_successor(nttmp2, 1);     if (nttmp2 == nt1) return -(i+2);
+               nttmp2 = prng_successor(nttmp2, 1);     if (nttmp2 == nt1) return -(i+3);
+               nttmp2 = prng_successor(nttmp2, 1);     if (nttmp2 == nt1) return -(i+4);
+               nttmp2 = prng_successor(nttmp2, 1);     if (nttmp2 == nt1) return -(i+5);
+               nttmp2 = prng_successor(nttmp2, 1);     if (nttmp2 == nt1) return -(i+6);
                nttmp2 = prng_successor(nttmp2, 1);     if (nttmp2 == nt1) return -(i+7);               
        }
        // either nt1 or nt2 are invalid nonces