X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/538300eed841e9c750ae7aee6ca358b844e539e1..b4a9d8419fde40cd39b8068ddfec34118b250c50:/common/legic_prng.c?ds=sidebyside diff --git a/common/legic_prng.c b/common/legic_prng.c index 54d2466e..4f3b1ffe 100644 --- a/common/legic_prng.c +++ b/common/legic_prng.c @@ -9,11 +9,13 @@ #include "legic_prng.h" struct lfsr { - uint8_t a; - uint8_t b; + uint8_t a; + uint8_t b; + uint32_t c; } lfsr; void legic_prng_init(uint8_t init) { + lfsr.c = 0; lfsr.a = init; if(init == 0) /* hack to get a always 0 keystream */ lfsr.b = 0; @@ -22,12 +24,17 @@ void legic_prng_init(uint8_t init) { } void legic_prng_forward(int count) { + lfsr.c += count; while(count--) { lfsr.a = lfsr.a >> 1 | (lfsr.a ^ lfsr.a >> 6) << 6; lfsr.b = lfsr.b >> 1 | (lfsr.b ^ lfsr.b >> 2 ^ lfsr.b >> 3 ^ lfsr.b >> 7) << 7; } } +int legic_prng_count() { + return lfsr.c; +} + uint8_t legic_prng_get_bit() { uint8_t idx = 7 - ( (lfsr.a & 4) | (lfsr.a >> 2 & 2) | (lfsr.a >> 4 & 1) ); return lfsr.b >> idx & 1;