From 30daf914cee4594c1482da861bfdcf7d7d16cfc5 Mon Sep 17 00:00:00 2001 From: iceman1001 Date: Fri, 28 Oct 2016 13:06:34 +0200 Subject: [PATCH] FIX: looping logic error, doesn't need to increase with 1, if we do 8 checks every turn... --- armsrc/iso14443a.c | 25 ++++++++++--------------- 1 file changed, 10 insertions(+), 15 deletions(-) diff --git a/armsrc/iso14443a.c b/armsrc/iso14443a.c index 570f028c..4bd55fb3 100644 --- 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 -- 2.39.2