CHG: Crapto1 v3.3 for the ARMSRC

[proxmark3-svn] / armsrc / crapto1.c

diff --git a/armsrc/crapto1.c b/armsrc/crapto1.c
index 8721375717f2364a57f8aa14e87b0c11086d5d06..4b4e240ed7bd44d63076e5277629357e728c0ecd 100644 (file)
--- a/armsrc/crapto1.c
+++ b/armsrc/crapto1.c
@@ -33,8 +33,7 @@ static void __attribute__((constructor)) fill_lut()
 \r
 static void quicksort(uint32_t* const start, uint32_t* const stop)\r
 {\r
-       uint32_t *it = start + 1, *rit = stop;\r
-       uint32_t tmp;\r
+       uint32_t *it = start + 1, *rit = stop, t;\r
 \r
        if(it > rit)\r
                return;\r
@@ -44,19 +43,13 @@ static void quicksort(uint32_t* const start, uint32_t* const stop)
                        ++it;\r
                else if(*rit > *start)\r
                        --rit;\r
-               else {\r
-                       tmp = *it;\r
-                       *it = *rit;\r
-                       *rit = tmp;\r
-               }\r
+               else\r
+                       t = *it,  *it = *rit, *rit = t;\r
 \r
        if(*rit >= *start)\r
                --rit;\r
-       if(rit != start) {\r
-               tmp = *rit;\r
-               *rit = *start;\r
-               *start = tmp;\r
-       }\r
+       if(rit != start)\r
+               t = *rit,  *rit = *start, *start = t;\r
 \r
        quicksort(start, rit - 1);\r
        quicksort(rit + 1, stop);\r
@@ -325,12 +318,10 @@ uint8_t lfsr_rollback_bit(struct Crypto1State *s, uint32_t in, int fb)
 {\r
        int out;\r
        uint8_t ret;\r
-       uint32_t tmp;\r
+       uint32_t t;\r
 \r
        s->odd &= 0xffffff;\r
-       tmp = s->odd;\r
-       s->odd = s->even;\r
-       s->even = tmp;\r
+       t = s->odd, s->odd = s->even, s->even = t;\r
 \r
        out = s->even & 1;\r
        out ^= LF_POLY_EVEN & (s->even >>= 1);\r
@@ -346,7 +337,8 @@ uint8_t lfsr_rollback_bit(struct Crypto1State *s, uint32_t in, int fb)
  */\r
 uint8_t lfsr_rollback_byte(struct Crypto1State *s, uint32_t in, int fb)\r
 {\r
-/*     int i, ret = 0;\r
+       /*\r
+       int i, ret = 0;\r
        for (i = 7; i >= 0; --i)\r
                ret |= lfsr_rollback_bit(s, BIT(in, i), fb) << i;\r
 */\r
@@ -367,7 +359,8 @@ uint8_t lfsr_rollback_byte(struct Crypto1State *s, uint32_t in, int fb)
  */\r
 uint32_t lfsr_rollback_word(struct Crypto1State *s, uint32_t in, int fb)\r
 {\r
-/*     int i;\r
+       /*\r
+       int i;\r
        uint32_t ret = 0;\r
        for (i = 31; i >= 0; --i)\r
                ret |= lfsr_rollback_bit(s, BEBIT(in, i), fb) << (i ^ 24);\r
@@ -435,6 +428,8 @@ int nonce_distance(uint32_t from, uint32_t to)
 static uint32_t fastfwd[2][8] = {\r
        { 0, 0x4BC53, 0xECB1, 0x450E2, 0x25E29, 0x6E27A, 0x2B298, 0x60ECB},\r
        { 0, 0x1D962, 0x4BC53, 0x56531, 0xECB1, 0x135D3, 0x450E2, 0x58980}};\r
+\r
+\r
 /** lfsr_prefix_ks\r
  *\r
  * Is an exported helper function from the common prefix attack\r
@@ -444,10 +439,12 @@ static uint32_t fastfwd[2][8] = {
  * encrypt the NACK which is observed when varying only the 3 last bits of Nr\r
  * only correct iff [NR_3] ^ NR_3 does not depend on Nr_3\r
  */\r
+ // TO VERIFY \r
 uint32_t *lfsr_prefix_ks(uint8_t ks[8], int isodd)\r
 {\r
-       uint32_t c, entry, *candidates = malloc(4 << 10);\r
-       int i, size = 0, good;\r
+       uint32_t *candidates = malloc(4 << 10);\r
+       uint32_t c,  entry;\r
+       int size = 0, i, good;\r
 \r
        if(!candidates)\r
                return 0;\r
@@ -503,6 +500,12 @@ check_pfx_parity(uint32_t prefix, uint32_t rresp, uint8_t parities[8][8],
 \r
 /** lfsr_common_prefix\r
  * Implentation of the common prefix attack.\r
+ * Requires the 28 bit constant prefix used as reader nonce (pfx)\r
+ * The reader response used (rr)\r
+ * The keystream used to encrypt the observed NACK's (ks)\r
+ * The parity bits (par)\r
+ * It returns a zero terminated list of possible cipher states after the\r
+ * tag nonce was fed in\r
  */\r
 struct Crypto1State*\r
 lfsr_common_prefix(uint32_t pfx, uint32_t rr, uint8_t ks[8], uint8_t par[8][8])\r
@@ -516,8 +519,9 @@ lfsr_common_prefix(uint32_t pfx, uint32_t rr, uint8_t ks[8], uint8_t par[8][8])
        s = statelist = malloc((sizeof *statelist) << 20);\r
        if(!s || !odd || !even) {\r
                free(statelist);\r
-               statelist = 0;\r
-               goto out;\r
+               free(odd);\r
+               free(even);\r
+               return 0;\r
        }\r
 \r
        for(o = odd; *o + 1; ++o)\r
@@ -529,8 +533,9 @@ lfsr_common_prefix(uint32_t pfx, uint32_t rr, uint8_t ks[8], uint8_t par[8][8])
                        }\r
 \r
        s->odd = s->even = 0;\r
-out:\r
+\r
        free(odd);\r
        free(even);\r
+\r
        return statelist;\r
 }\r