FIX, Coverity, Unsigned compared against 0. CID #212326, keyNBr will never be negative.

[proxmark3-svn] / client / cmdhfmfhard.c

diff --git a/client/cmdhfmfhard.c b/client/cmdhfmfhard.c
index 9a938d6421aa428ced33e7d6b27e01e32b161758..6a5c439d5afaafc5ad05b2e2a30750b81a83e82b 100644 (file)
--- a/client/cmdhfmfhard.c
+++ b/client/cmdhfmfhard.c
@@ -30,7 +30,7 @@
 // uint32_t test_state_even = 0;
 
 #define CONFIDENCE_THRESHOLD   0.95            // Collect nonces until we are certain enough that the following brute force is successfull
 // uint32_t test_state_even = 0;
 
 #define CONFIDENCE_THRESHOLD   0.95            // Collect nonces until we are certain enough that the following brute force is successfull

-#define GOOD_BYTES_REQUIRED            60
+#define GOOD_BYTES_REQUIRED            30

 
 
 static const float p_K[257] = {                // the probability that a random nonce has a Sum Property == K 
 
 
 static const float p_K[257] = {                // the probability that a random nonce has a Sum Property == K 


@@ -83,19 +83,19 @@ typedef struct noncelist {
        float Sum8_prob;
        bool updated;
        noncelistentry_t *first;
        float Sum8_prob;
        bool updated;
        noncelistentry_t *first;

+       float score1, score2;

 } noncelist_t;
 
 
 static uint32_t cuid;
 static noncelist_t nonces[256];
 } noncelist_t;
 
 
 static uint32_t cuid;
 static noncelist_t nonces[256];

+static uint8_t best_first_bytes[256];

 static uint16_t first_byte_Sum = 0;
 static uint16_t first_byte_num = 0;
 static uint16_t num_good_first_bytes = 0;
 static uint64_t maximum_states = 0;
 static uint64_t known_target_key;
 
 static uint16_t first_byte_Sum = 0;
 static uint16_t first_byte_num = 0;
 static uint16_t num_good_first_bytes = 0;
 static uint64_t maximum_states = 0;
 static uint64_t known_target_key;
 

-#define MAX_BEST_BYTES 256
-static uint8_t best_first_bytes[MAX_BEST_BYTES];

 
 
 typedef enum {
 
 
 typedef enum {


@@ -199,12 +199,12 @@ static uint16_t PartialSumProperty(uint32_t state, odd_even_t odd_even)
 }
 
 
 }
 
 

-static uint16_t SumProperty(struct Crypto1State *s)
-{
-       uint16_t sum_odd = PartialSumProperty(s->odd, ODD_STATE);
-       uint16_t sum_even = PartialSumProperty(s->even, EVEN_STATE);
-       return (sum_odd*(16-sum_even) + (16-sum_odd)*sum_even);
-}
+// static uint16_t SumProperty(struct Crypto1State *s)
+// {
+       // uint16_t sum_odd = PartialSumProperty(s->odd, ODD_STATE);
+       // uint16_t sum_even = PartialSumProperty(s->even, EVEN_STATE);
+       // return (sum_odd*(16-sum_even) + (16-sum_odd)*sum_even);
+// }

 
 
 static double p_hypergeometric(uint16_t N, uint16_t K, uint16_t n, uint16_t k) 
 
 
 static double p_hypergeometric(uint16_t N, uint16_t K, uint16_t n, uint16_t k) 


@@ -266,15 +266,42 @@ static float sum_probability(uint16_t K, uint16_t n, uint16_t k)
 }
 
                
 }
 
                

+
+       
+static inline uint_fast8_t common_bits(uint_fast8_t bytes_diff) 
+{
+       static const uint_fast8_t common_bits_LUT[256] = {
+               8, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+               4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+               5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+               4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+               6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+               4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+               5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+               4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+               7, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+               4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+               5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+               4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+               6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+               4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+               5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+               4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0
+       };
+
+       return common_bits_LUT[bytes_diff];
+}
+
+

 static void Tests()
 {
 static void Tests()
 {

-       printf("Tests: Partial Statelist sizes\n");
-       for (uint16_t i = 0; i <= 16; i+=2) {
-               printf("Partial State List Odd [%2d] has %8d entries\n", i, partial_statelist[i].len[ODD_STATE]);
-       }
-       for (uint16_t i = 0; i <= 16; i+=2) {
-               printf("Partial State List Even [%2d] has %8d entries\n", i, partial_statelist[i].len[EVEN_STATE]);
-       }
+       // printf("Tests: Partial Statelist sizes\n");
+       // for (uint16_t i = 0; i <= 16; i+=2) {
+               // printf("Partial State List Odd [%2d] has %8d entries\n", i, partial_statelist[i].len[ODD_STATE]);
+       // }
+       // for (uint16_t i = 0; i <= 16; i+=2) {
+               // printf("Partial State List Even      [%2d] has %8d entries\n", i, partial_statelist[i].len[EVEN_STATE]);
+       // }

        
        // #define NUM_STATISTICS 100000
        // uint32_t statistics_odd[17];
        
        // #define NUM_STATISTICS 100000
        // uint32_t statistics_odd[17];


@@ -347,61 +374,67 @@ static void Tests()
        // printf("p_hypergeometric(256, 1, 1, 1) = %0.8f\n", p_hypergeometric(256, 1, 1, 1));
        // printf("p_hypergeometric(256, 1, 1, 0) = %0.8f\n", p_hypergeometric(256, 1, 1, 0));
        
        // printf("p_hypergeometric(256, 1, 1, 1) = %0.8f\n", p_hypergeometric(256, 1, 1, 1));
        // printf("p_hypergeometric(256, 1, 1, 0) = %0.8f\n", p_hypergeometric(256, 1, 1, 0));
        

-       struct Crypto1State *pcs;
-       pcs = crypto1_create(0xffffffffffff);
-       printf("\nTests: for key = 0xffffffffffff:\nSum(a0) = %d\nodd_state =  0x%06x\neven_state = 0x%06x\n", 
-               SumProperty(pcs), pcs->odd & 0x00ffffff, pcs->even & 0x00ffffff);
-       crypto1_byte(pcs, (cuid >> 24) ^ best_first_bytes[0], true);
-       printf("After adding best first byte 0x%02x:\nSum(a8) = %d\nodd_state =  0x%06x\neven_state = 0x%06x\n",
-               best_first_bytes[0],
-               SumProperty(pcs),
-               pcs->odd & 0x00ffffff, pcs->even & 0x00ffffff);
-       //test_state_odd = pcs->odd & 0x00ffffff;
-       //test_state_even = pcs->even & 0x00ffffff;
-       crypto1_destroy(pcs);
-       pcs = crypto1_create(0xa0a1a2a3a4a5);
-       printf("Tests: for key = 0xa0a1a2a3a4a5:\nSum(a0) = %d\nodd_state =  0x%06x\neven_state = 0x%06x\n",
-               SumProperty(pcs), pcs->odd & 0x00ffffff, pcs->even & 0x00ffffff);
-       crypto1_byte(pcs, (cuid >> 24) ^ best_first_bytes[0], true);
-       printf("After adding best first byte 0x%02x:\nSum(a8) = %d\nodd_state =  0x%06x\neven_state = 0x%06x\n",
-               best_first_bytes[0],
-               SumProperty(pcs),
-               pcs->odd & 0x00ffffff, pcs->even & 0x00ffffff);
-       // test_state_odd = pcs->odd & 0x00ffffff;
-       // test_state_even = pcs->even & 0x00ffffff;
-       crypto1_destroy(pcs);
-       pcs = crypto1_create(0xa6b9aa97b955);
-       printf("Tests: for key = 0xa6b9aa97b955:\nSum(a0) = %d\nodd_state =  0x%06x\neven_state = 0x%06x\n",
-               SumProperty(pcs), pcs->odd & 0x00ffffff, pcs->even & 0x00ffffff);
-       crypto1_byte(pcs, (cuid >> 24) ^ best_first_bytes[0], true);
-       printf("After adding best first byte 0x%02x:\nSum(a8) = %d\nodd_state =  0x%06x\neven_state = 0x%06x\n",
-               best_first_bytes[0],
-               SumProperty(pcs),
-               pcs->odd & 0x00ffffff, pcs->even & 0x00ffffff);
+       // struct Crypto1State *pcs;
+       // pcs = crypto1_create(0xffffffffffff);
+       // printf("\nTests: for key = 0xffffffffffff:\nSum(a0) = %d\nodd_state =  0x%06x\neven_state = 0x%06x\n", 
+               // SumProperty(pcs), pcs->odd & 0x00ffffff, pcs->even & 0x00ffffff);
+       // crypto1_byte(pcs, (cuid >> 24) ^ best_first_bytes[0], true);
+       // printf("After adding best first byte 0x%02x:\nSum(a8) = %d\nodd_state =  0x%06x\neven_state = 0x%06x\n",
+               // best_first_bytes[0],
+               // SumProperty(pcs),
+               // pcs->odd & 0x00ffffff, pcs->even & 0x00ffffff);
+       // //test_state_odd = pcs->odd & 0x00ffffff;
+       // //test_state_even = pcs->even & 0x00ffffff;
+       // crypto1_destroy(pcs);
+       // pcs = crypto1_create(0xa0a1a2a3a4a5);
+       // printf("Tests: for key = 0xa0a1a2a3a4a5:\nSum(a0) = %d\nodd_state =  0x%06x\neven_state = 0x%06x\n",
+               // SumProperty(pcs), pcs->odd & 0x00ffffff, pcs->even & 0x00ffffff);
+       // crypto1_byte(pcs, (cuid >> 24) ^ best_first_bytes[0], true);
+       // printf("After adding best first byte 0x%02x:\nSum(a8) = %d\nodd_state =  0x%06x\neven_state = 0x%06x\n",
+               // best_first_bytes[0],
+               // SumProperty(pcs),
+               // pcs->odd & 0x00ffffff, pcs->even & 0x00ffffff);
+       // //test_state_odd = pcs->odd & 0x00ffffff;
+       // //test_state_even = pcs->even & 0x00ffffff;
+       // crypto1_destroy(pcs);
+       // pcs = crypto1_create(0xa6b9aa97b955);
+       // printf("Tests: for key = 0xa6b9aa97b955:\nSum(a0) = %d\nodd_state =  0x%06x\neven_state = 0x%06x\n",
+               // SumProperty(pcs), pcs->odd & 0x00ffffff, pcs->even & 0x00ffffff);
+       // crypto1_byte(pcs, (cuid >> 24) ^ best_first_bytes[0], true);
+       // printf("After adding best first byte 0x%02x:\nSum(a8) = %d\nodd_state =  0x%06x\neven_state = 0x%06x\n",
+               // best_first_bytes[0],
+               // SumProperty(pcs),
+               // pcs->odd & 0x00ffffff, pcs->even & 0x00ffffff);

        //test_state_odd = pcs->odd & 0x00ffffff;
        //test_state_even = pcs->even & 0x00ffffff;
        //test_state_odd = pcs->odd & 0x00ffffff;
        //test_state_even = pcs->even & 0x00ffffff;

-       crypto1_destroy(pcs);
-
+       // crypto1_destroy(pcs);

 
        
 
        

-       printf("\nTests: number of states with BitFlipProperty: %d, (= %1.3f%% of total states)\n", statelist_bitflip.len[0], 100.0 * statelist_bitflip.len[0] / (1<<20));
+       
+       // printf("\nTests: number of states with BitFlipProperty: %d, (= %1.3f%% of total states)\n", statelist_bitflip.len[0], 100.0 * statelist_bitflip.len[0] / (1<<20));

 
        printf("\nTests: Actual BitFlipProperties odd/even:\n");
        for (uint16_t i = 0; i < 256; i++) {
 
        printf("\nTests: Actual BitFlipProperties odd/even:\n");
        for (uint16_t i = 0; i < 256; i++) {

-               printf("[%02x]:%c%c ", i, nonces[i].BitFlip[ODD_STATE]?'o':' ', nonces[i].BitFlip[EVEN_STATE]?'e':' ');
+               printf("[%02x]:%c  ", i, nonces[i].BitFlip[ODD_STATE]?'o':nonces[i].BitFlip[EVEN_STATE]?'e':' ');

                if (i % 8 == 7) {
                        printf("\n");
                }
        }
        
                if (i % 8 == 7) {
                        printf("\n");
                }
        }
        

-       printf("\nTests: Best %d first bytes:\n", MAX_BEST_BYTES);
-       for (uint16_t i = 0; i < MAX_BEST_BYTES; i++) {
+       printf("\nTests: Sorted First Bytes:\n");
+       for (uint16_t i = 0; i < 256; i++) {

                uint8_t best_byte = best_first_bytes[i];
                uint8_t best_byte = best_first_bytes[i];

-               uint16_t best_num = nonces[best_byte].num;
-               uint16_t best_sum = nonces[best_byte].Sum;
-               uint16_t best_sum8 = nonces[best_byte].Sum8_guess;
-               float confidence = nonces[best_byte].Sum8_prob;
-               printf("#%03d Byte: %02x, n = %2d, k = %2d, Sum(a8): %3d, Confidence: %2.1f%%\n", i, best_byte, best_num, best_sum, best_sum8, confidence*100);
+               printf("#%03d Byte: %02x, n = %3d, k = %3d, Sum(a8): %3d, Confidence: %5.1f%%, Bitflip: %c\n", 
+               //printf("#%03d Byte: %02x, n = %3d, k = %3d, Sum(a8): %3d, Confidence: %5.1f%%, Bitflip: %c, score1: %1.5f, score2: %1.0f\n", 
+                       i, best_byte, 
+                       nonces[best_byte].num,
+                       nonces[best_byte].Sum,
+                       nonces[best_byte].Sum8_guess,
+                       nonces[best_byte].Sum8_prob * 100,
+                       nonces[best_byte].BitFlip[ODD_STATE]?'o':nonces[best_byte].BitFlip[EVEN_STATE]?'e':' '
+                       //nonces[best_byte].score1,
+                       //nonces[best_byte].score2
+                       );

        }
        
        // printf("\nTests: parity performance\n");
        }
        
        // printf("\nTests: parity performance\n");


@@ -419,42 +452,31 @@ static void Tests()
        // }
        // printf("parsum newparity = %d, time = %1.5fsec\n", par_sum, (float)(clock() - time1p)/CLOCKS_PER_SEC);
 
        // }
        // printf("parsum newparity = %d, time = %1.5fsec\n", par_sum, (float)(clock() - time1p)/CLOCKS_PER_SEC);
 

-}
-

 
 

-static int common_bits(uint8_t byte1, uint8_t byte2) 
-{
-       uint8_t common_bits = byte1 ^ byte2;
-       uint8_t j = 0;
-       while ((common_bits & 0x01) == 0 && j < 8) {
-               j++;
-               common_bits >>= 1;
-       }
-       return j;

 }
 
 
 static void sort_best_first_bytes(void)
 {
 }
 
 
 static void sort_best_first_bytes(void)
 {

-       // first, sort based on probability for correct guess   
+       // sort based on probability for correct guess  

        for (uint16_t i = 0; i < 256; i++ ) {
                uint16_t j = 0;
                float prob1 = nonces[i].Sum8_prob;
                float prob2 = nonces[best_first_bytes[0]].Sum8_prob;
        for (uint16_t i = 0; i < 256; i++ ) {
                uint16_t j = 0;
                float prob1 = nonces[i].Sum8_prob;
                float prob2 = nonces[best_first_bytes[0]].Sum8_prob;

-               while (prob1 < prob2 && j < MAX_BEST_BYTES-1) {
+               while (prob1 < prob2 && j < i) {

                        prob2 = nonces[best_first_bytes[++j]].Sum8_prob;
                }
                        prob2 = nonces[best_first_bytes[++j]].Sum8_prob;
                }

-               if (prob1 >= prob2) {
-                       for (uint16_t k = MAX_BEST_BYTES-1; k > j; k--) {
+               if (j < i) {
+                       for (uint16_t k = i; k > j; k--) {

                                best_first_bytes[k] = best_first_bytes[k-1];
                        }
                                best_first_bytes[k] = best_first_bytes[k-1];
                        }

+               }

                        best_first_bytes[j] = i;
                }
                        best_first_bytes[j] = i;
                }

-       }

 
 

-       // determine, how many are above the CONFIDENCE_THRESHOLD
+       // determine how many are above the CONFIDENCE_THRESHOLD

        uint16_t num_good_nonces = 0;
        uint16_t num_good_nonces = 0;

-       for (uint16_t i = 0; i < MAX_BEST_BYTES; i++) {
+       for (uint16_t i = 0; i < 256; i++) {

                if (nonces[best_first_bytes[i]].Sum8_prob > CONFIDENCE_THRESHOLD) {
                        ++num_good_nonces;
                }
                if (nonces[best_first_bytes[i]].Sum8_prob > CONFIDENCE_THRESHOLD) {
                        ++num_good_nonces;
                }


@@ -485,12 +507,13 @@ static void sort_best_first_bytes(void)
                if (nonces[best_first_bytes[i]].BitFlip[ODD_STATE] || nonces[best_first_bytes[i]].BitFlip[EVEN_STATE]) {
                        bitflip_prob = 0.09375;
                }
                if (nonces[best_first_bytes[i]].BitFlip[ODD_STATE] || nonces[best_first_bytes[i]].BitFlip[EVEN_STATE]) {
                        bitflip_prob = 0.09375;
                }

+               nonces[best_first_bytes[i]].score1 = p_K[sum8] * bitflip_prob;

                if (p_K[sum8] * bitflip_prob <= min_p_K) {
                        min_p_K = p_K[sum8] * bitflip_prob;
                if (p_K[sum8] * bitflip_prob <= min_p_K) {
                        min_p_K = p_K[sum8] * bitflip_prob;

-                       best_first_byte = i;

                }
        }
 
                }
        }
 

+

        // use number of commmon bits as a tie breaker
        uint16_t max_common_bits = 0;
        for (uint16_t i = 0; i < num_good_nonces; i++) {
        // use number of commmon bits as a tie breaker
        uint16_t max_common_bits = 0;
        for (uint16_t i = 0; i < num_good_nonces; i++) {


@@ -501,8 +524,9 @@ static void sort_best_first_bytes(void)
                if (p_K[nonces[best_first_bytes[i]].Sum8_guess] * bitflip_prob == min_p_K) {
                        uint16_t sum_common_bits = 0;
                        for (uint16_t j = 0; j < num_good_nonces; j++) {
                if (p_K[nonces[best_first_bytes[i]].Sum8_guess] * bitflip_prob == min_p_K) {
                        uint16_t sum_common_bits = 0;
                        for (uint16_t j = 0; j < num_good_nonces; j++) {

-                               sum_common_bits += common_bits(best_first_bytes[i],best_first_bytes[j]);
+                               sum_common_bits += common_bits(best_first_bytes[i] ^ best_first_bytes[j]);

                        }
                        }

+                       nonces[best_first_bytes[i]].score2 = sum_common_bits;

                        if (sum_common_bits > max_common_bits) {
                                max_common_bits = sum_common_bits;
                                best_first_byte = i;
                        if (sum_common_bits > max_common_bits) {
                                max_common_bits = sum_common_bits;
                                best_first_byte = i;


@@ -510,7 +534,7 @@ static void sort_best_first_bytes(void)
                }
        }       
 
                }
        }       
 

-       // swap best possible first bytes to the pole position
+       // swap best possible first byte to the pole position

        uint16_t temp = best_first_bytes[0];
        best_first_bytes[0] = best_first_bytes[best_first_byte];
        best_first_bytes[best_first_byte] = temp;
        uint16_t temp = best_first_bytes[0];
        best_first_bytes[0] = best_first_bytes[best_first_byte];
        best_first_bytes[best_first_byte] = temp;


@@ -520,9 +544,6 @@ static void sort_best_first_bytes(void)
 
 static uint16_t estimate_second_byte_sum(void) 
 {
 
 static uint16_t estimate_second_byte_sum(void) 
 {

-       for (uint16_t i = 0; i < MAX_BEST_BYTES; i++) {
-               best_first_bytes[i] = 0;
-       }

        
        for (uint16_t first_byte = 0; first_byte < 256; first_byte++) {
                float Sum8_prob = 0.0;
        
        for (uint16_t first_byte = 0; first_byte < 256; first_byte++) {
                float Sum8_prob = 0.0;


@@ -544,7 +565,7 @@ static uint16_t estimate_second_byte_sum(void)
        sort_best_first_bytes();
 
        uint16_t num_good_nonces = 0;
        sort_best_first_bytes();
 
        uint16_t num_good_nonces = 0;

-       for (uint16_t i = 0; i < MAX_BEST_BYTES; i++) {
+       for (uint16_t i = 0; i < 256; i++) {

                if (nonces[best_first_bytes[i]].Sum8_prob > CONFIDENCE_THRESHOLD) {
                        ++num_good_nonces;
                }
                if (nonces[best_first_bytes[i]].Sum8_prob > CONFIDENCE_THRESHOLD) {
                        ++num_good_nonces;
                }


@@ -596,12 +617,36 @@ static int read_nonce_file(void)
 }
 
 
 }
 
 

+static void Check_for_FilterFlipProperties(void)
+{
+       printf("Checking for Filter Flip Properties...\n");
+
+       for (uint16_t i = 0; i < 256; i++) {
+               nonces[i].BitFlip[ODD_STATE] = false;
+               nonces[i].BitFlip[EVEN_STATE] = false;
+       }
+       
+       for (uint16_t i = 0; i < 256; i++) {
+               uint8_t parity1 = (nonces[i].first->par_enc) >> 3;                              // parity of first byte
+               uint8_t parity2_odd = (nonces[i^0x80].first->par_enc) >> 3;     // XOR 0x80 = last bit flipped
+               uint8_t parity2_even = (nonces[i^0x40].first->par_enc) >> 3;    // XOR 0x40 = second last bit flipped
+               
+               if (parity1 == parity2_odd) {                           // has Bit Flip Property for odd bits
+                       nonces[i].BitFlip[ODD_STATE] = true;
+               } else if (parity1 == parity2_even) {           // has Bit Flip Property for even bits
+                       nonces[i].BitFlip[EVEN_STATE] = true;
+               }
+       }
+}
+
+

 static int acquire_nonces(uint8_t blockNo, uint8_t keyType, uint8_t *key, uint8_t trgBlockNo, uint8_t trgKeyType, bool nonce_file_write, bool slow)
 {
        clock_t time1 = clock();
        bool initialize = true;
        bool field_off = false;
        bool finished = false;
 static int acquire_nonces(uint8_t blockNo, uint8_t keyType, uint8_t *key, uint8_t trgBlockNo, uint8_t trgKeyType, bool nonce_file_write, bool slow)
 {
        clock_t time1 = clock();
        bool initialize = true;
        bool field_off = false;
        bool finished = false;

+       bool filter_flip_checked = false;

        uint32_t flags = 0;
        uint8_t write_buf[9];
        uint32_t total_num_nonces = 0;
        uint32_t flags = 0;
        uint8_t write_buf[9];
        uint32_t total_num_nonces = 0;


@@ -673,6 +718,10 @@ static int acquire_nonces(uint8_t blockNo, uint8_t keyType, uint8_t *key, uint8_
                
                if (first_byte_num == 256 ) {
                        // printf("first_byte_num = %d, first_byte_Sum = %d\n", first_byte_num, first_byte_Sum);
                
                if (first_byte_num == 256 ) {
                        // printf("first_byte_num = %d, first_byte_Sum = %d\n", first_byte_num, first_byte_Sum);

+                       if (!filter_flip_checked) {
+                               Check_for_FilterFlipProperties();
+                               filter_flip_checked = true;
+                       }

                        num_good_first_bytes = estimate_second_byte_sum();
                        if (total_num_nonces > next_fivehundred) {
                                next_fivehundred = (total_num_nonces/500+1) * 500;
                        num_good_first_bytes = estimate_second_byte_sum();
                        if (total_num_nonces > next_fivehundred) {
                                next_fivehundred = (total_num_nonces/500+1) * 500;


@@ -785,71 +834,66 @@ static void init_BitFlip_statelist(void)
 }
 
                
 }
 
                

-static void add_state(statelist_t *sl, uint32_t state, odd_even_t odd_even)
-{
-       uint32_t *p;
-
-       p = sl->states[odd_even];
-       p += sl->len[odd_even];
-       *p = state;
-       sl->len[odd_even]++;
-}
-
-
-static uint32_t *find_first_state(uint32_t state, uint32_t mask, partial_indexed_statelist_t *sl, odd_even_t odd_even)
+static inline uint32_t *find_first_state(uint32_t state, uint32_t mask, partial_indexed_statelist_t *sl, odd_even_t odd_even)

 {
        uint32_t *p = sl->index[odd_even][(state & mask) >> (20-STATELIST_INDEX_WIDTH)];                // first Bits as index
 
        if (p == NULL) return NULL;
 {
        uint32_t *p = sl->index[odd_even][(state & mask) >> (20-STATELIST_INDEX_WIDTH)];                // first Bits as index
 
        if (p == NULL) return NULL;

-       while ((*p & mask) < (state & mask)) p++;
+       while (*p < (state & mask)) p++;

        if (*p == 0xffffffff) return NULL;                                      // reached end of list, no match
        if ((*p & mask) == (state & mask)) return p;            // found a match.
        return NULL;                                                                            // no match
 } 
 
 
        if (*p == 0xffffffff) return NULL;                                      // reached end of list, no match
        if ((*p & mask) == (state & mask)) return p;            // found a match.
        return NULL;                                                                            // no match
 } 
 
 

-static bool remaining_bits_match(uint8_t num_common_bits, uint8_t byte1, uint8_t byte2, uint32_t state1, uint32_t state2, odd_even_t odd_even)
+static inline bool /*__attribute__((always_inline))*/ invariant_holds(uint_fast8_t byte_diff, uint_fast32_t state1, uint_fast32_t state2, uint_fast8_t bit, uint_fast8_t state_bit)

 {
 {

-       uint8_t j = num_common_bits;
-       if (odd_even == ODD_STATE) {
-               j |= 0x01;                      // consider the next odd bit
-       } else {
-               j = (j+1) & 0xfe;       // consider the next even bit
-       }
-               
-       while (j <= 7) {
-               if (j != num_common_bits) {                     // this is not the first differing bit, we need first to check if the invariant still holds
-                       uint32_t bit_diff = ((byte1 ^ byte2) << (17-j)) & 0x00010000;                                   // difference of (j-1)th bit -> bit 16
-                       uint32_t filter_diff = filter(state1 >> (4-j/2)) ^ filter(state2 >> (4-j/2));   // difference in filter function -> bit 0
-                       uint32_t mask_y12_y13 = 0x000000c0 >> (j/2);
-                       uint32_t state_diff = (state1 ^ state2) & mask_y12_y13;                                                 // difference in state bits 12 and 13 -> bits 6/7 ... 3/4
-                       uint32_t all_diff = parity(bit_diff | state_diff | filter_diff);                                // use parity function to XOR all 4 bits
-                       if (all_diff) {                 // invariant doesn't hold any more. Accept this state.
-                               // if ((odd_even == ODD_STATE && state1 == test_state_odd)
-                                       // || (odd_even == EVEN_STATE && state1 == test_state_even)) {
-                                       // printf("remaining_bits_match(): %s test state: Invariant doesn't hold. Bytes = %02x, %02x, Common Bits=%d, Testing Bit %d, State1=0x%08x, State2=0x%08x\n", 
-                                               // odd_even==ODD_STATE?"odd":"even", byte1, byte2, num_common_bits, j, state1, state2);
-                               // }
-                               return true;
-                       }
+       uint_fast8_t j_1_bit_mask = 0x01 << (bit-1);
+       uint_fast8_t bit_diff = byte_diff & j_1_bit_mask;                                                                               // difference of (j-1)th bit
+       uint_fast8_t filter_diff = filter(state1 >> (4-state_bit)) ^ filter(state2 >> (4-state_bit));   // difference in filter function
+       uint_fast8_t mask_y12_y13 = 0xc0 >> state_bit;
+       uint_fast8_t state_bits_diff = (state1 ^ state2) & mask_y12_y13;                                                // difference in state bits 12 and 13
+       uint_fast8_t all_diff = evenparity8(bit_diff ^ state_bits_diff ^ filter_diff);                  // use parity function to XOR all bits
+       return !all_diff;
+}
+
+
+static inline bool /*__attribute__((always_inline))*/ invalid_state(uint_fast8_t byte_diff, uint_fast32_t state1, uint_fast32_t state2, uint_fast8_t bit, uint_fast8_t state_bit)
+{
+       uint_fast8_t j_bit_mask = 0x01 << bit;
+       uint_fast8_t bit_diff = byte_diff & j_bit_mask;                                                                                 // difference of jth bit
+       uint_fast8_t mask_y13_y16 = 0x48 >> state_bit;
+       uint_fast8_t state_bits_diff = (state1 ^ state2) & mask_y13_y16;                                                // difference in state bits 13 and 16
+       uint_fast8_t all_diff = evenparity8(bit_diff ^ state_bits_diff);                                                // use parity function to XOR all bits
+       return all_diff;
+}
+
+
+static inline bool remaining_bits_match(uint_fast8_t num_common_bits, uint_fast8_t byte_diff, uint_fast32_t state1, uint_fast32_t state2, odd_even_t odd_even)
+{
+       if (odd_even) {
+               // odd bits
+               switch (num_common_bits) {
+                       case 0: if (!invariant_holds(byte_diff, state1, state2, 1, 0)) return true;
+                       case 1: if (invalid_state(byte_diff, state1, state2, 1, 0)) return false;
+                       case 2: if (!invariant_holds(byte_diff, state1, state2, 3, 1)) return true;
+                       case 3: if (invalid_state(byte_diff, state1, state2, 3, 1)) return false;
+                       case 4: if (!invariant_holds(byte_diff, state1, state2, 5, 2)) return true;
+                       case 5: if (invalid_state(byte_diff, state1, state2, 5, 2)) return false;
+                       case 6: if (!invariant_holds(byte_diff, state1, state2, 7, 3)) return true;
+                       case 7: if (invalid_state(byte_diff, state1, state2, 7, 3)) return false;

                }
                }

-               // check for validity of state candidate
-               uint32_t bit_diff = ((byte1 ^ byte2) << (16-j)) & 0x00010000;                                           // difference of jth bit -> bit 16
-               uint32_t mask_y13_y16 = 0x00000048 >> (j/2);
-               uint32_t state_diff = (state1 ^ state2) & mask_y13_y16;                                                         // difference in state bits 13 and 16 -> bits 3/6 ... 0/3
-               uint32_t all_diff = parity(bit_diff | state_diff);                                                                      // use parity function to XOR all 3 bits
-               if (all_diff) {                         // not a valid state
-                       // if ((odd_even == ODD_STATE && state1 == test_state_odd)
-                               // || (odd_even == EVEN_STATE && state1 == test_state_even)) {
-                               // printf("remaining_bits_match(): %s test state: Invalid state. Bytes = %02x, %02x, Common Bits=%d, Testing Bit %d, State1=0x%08x, State2=0x%08x\n", 
-                                       // odd_even==ODD_STATE?"odd":"even", byte1, byte2, num_common_bits, j, state1, state2);
-                               // printf("                        byte1^byte2: 0x%02x, bit_diff: 0x%08x, state_diff: 0x%08x, all_diff: 0x%08x\n", 
-                                       // byte1^byte2, bit_diff, state_diff, all_diff);
-                       // }
-                       return false;
+       } else {
+               // even bits
+               switch (num_common_bits) {      
+                       case 0: if (invalid_state(byte_diff, state1, state2, 0, 0)) return false;
+                       case 1: if (!invariant_holds(byte_diff, state1, state2, 2, 1)) return true;
+                       case 2: if (invalid_state(byte_diff, state1, state2, 2, 1)) return false;
+                       case 3: if (!invariant_holds(byte_diff, state1, state2, 4, 2)) return true;
+                       case 4: if (invalid_state(byte_diff, state1, state2, 4, 2)) return false;
+                       case 5: if (!invariant_holds(byte_diff, state1, state2, 6, 3)) return true;
+                       case 6: if (invalid_state(byte_diff, state1, state2, 6, 3)) return false;

                }
                }

-               // continue checking for the next bit
-               j += 2;

        } 
        
        return true;                                    // valid state
        } 
        
        return true;                                    // valid state


@@ -860,25 +904,13 @@ static bool all_other_first_bytes_match(uint32_t state, odd_even_t odd_even)
 {
        for (uint16_t i = 1; i < num_good_first_bytes; i++) {
                uint16_t sum_a8 = nonces[best_first_bytes[i]].Sum8_guess;
 {
        for (uint16_t i = 1; i < num_good_first_bytes; i++) {
                uint16_t sum_a8 = nonces[best_first_bytes[i]].Sum8_guess;

-               uint8_t j = 0; // number of common bits
-               uint8_t common_bits = best_first_bytes[0] ^ best_first_bytes[i];
+               uint_fast8_t bytes_diff = best_first_bytes[0] ^ best_first_bytes[i];
+               uint_fast8_t j = common_bits(bytes_diff);

                uint32_t mask = 0xfffffff0;
                if (odd_even == ODD_STATE) {
                uint32_t mask = 0xfffffff0;
                if (odd_even == ODD_STATE) {

-                       while ((common_bits & 0x01) == 0 && j < 8) {
-                               j++;
-                               common_bits >>= 1;
-                               if (j % 2 == 0) {               // the odd bits
-                                       mask >>= 1;
-                               }
-                       }
+                       mask >>= j/2;

                } else {
                } else {

-                       while ((common_bits & 0x01) == 0 && j < 8) {
-                               j++;
-                               common_bits >>= 1;
-                               if (j % 2 == 1) {               // the even bits
-                                       mask >>= 1;
-                               }
-                       }
+                       mask >>= (j+1)/2;

                }
                mask &= 0x000fffff;
                //printf("bytes 0x%02x and 0x%02x: %d common bits, mask = 0x%08x, state = 0x%08x, sum_a8 = %d", best_first_bytes[0], best_first_bytes[i], j, mask, state, sum_a8);
                }
                mask &= 0x000fffff;
                //printf("bytes 0x%02x and 0x%02x: %d common bits, mask = 0x%08x, state = 0x%08x, sum_a8 = %d", best_first_bytes[0], best_first_bytes[i], j, mask, state, sum_a8);


@@ -891,7 +923,7 @@ static bool all_other_first_bytes_match(uint32_t state, odd_even_t odd_even)
                                        uint32_t *p = find_first_state(state, mask, &partial_statelist[part_sum_a8], odd_even);
                                        if (p != NULL) {
                                                while ((state & mask) == (*p & mask) && (*p != 0xffffffff)) {
                                        uint32_t *p = find_first_state(state, mask, &partial_statelist[part_sum_a8], odd_even);
                                        if (p != NULL) {
                                                while ((state & mask) == (*p & mask) && (*p != 0xffffffff)) {

-                                                       if (remaining_bits_match(j, best_first_bytes[0], best_first_bytes[i], state, (state&0x00fffff0) | *p, odd_even)) {
+                                                       if (remaining_bits_match(j, bytes_diff, state, (state&0x00fffff0) | *p, odd_even)) {

                                                                found_match = true;
                                                                // if ((odd_even == ODD_STATE && state == test_state_odd)
                                                                        // || (odd_even == EVEN_STATE && state == test_state_even)) {
                                                                found_match = true;
                                                                // if ((odd_even == ODD_STATE && state == test_state_odd)
                                                                        // || (odd_even == EVEN_STATE && state == test_state_even)) {


@@ -936,25 +968,13 @@ static bool all_bit_flips_match(uint32_t state, odd_even_t odd_even)
 {
        for (uint16_t i = 0; i < 256; i++) {
                if (nonces[i].BitFlip[odd_even] && i != best_first_bytes[0]) {
 {
        for (uint16_t i = 0; i < 256; i++) {
                if (nonces[i].BitFlip[odd_even] && i != best_first_bytes[0]) {

-                       uint8_t j = 0; // number of common bits
-                       uint8_t common_bits = best_first_bytes[0] ^ i;
+                       uint_fast8_t bytes_diff = best_first_bytes[0] ^ i;
+                       uint_fast8_t j = common_bits(bytes_diff);

                        uint32_t mask = 0xfffffff0;
                        if (odd_even == ODD_STATE) {
                        uint32_t mask = 0xfffffff0;
                        if (odd_even == ODD_STATE) {

-                               while ((common_bits & 0x01) == 0 && j < 8) {
-                                       j++;
-                                       common_bits >>= 1;
-                                       if (j % 2 == 0) {               // the odd bits
-                                               mask >>= 1;
-                                       }
-                               }
+                               mask >>= j/2;

                        } else {
                        } else {

-                               while ((common_bits & 0x01) == 0 && j < 8) {
-                                       j++;
-                                       common_bits >>= 1;
-                                       if (j % 2 == 1) {               // the even bits
-                                               mask >>= 1;
-                                       }
-                               }
+                               mask >>= (j+1)/2;

                        }
                        mask &= 0x000fffff;
                        //printf("bytes 0x%02x and 0x%02x: %d common bits, mask = 0x%08x, state = 0x%08x, sum_a8 = %d", best_first_bytes[0], best_first_bytes[i], j, mask, state, sum_a8);
                        }
                        mask &= 0x000fffff;
                        //printf("bytes 0x%02x and 0x%02x: %d common bits, mask = 0x%08x, state = 0x%08x, sum_a8 = %d", best_first_bytes[0], best_first_bytes[i], j, mask, state, sum_a8);


@@ -962,7 +982,7 @@ static bool all_bit_flips_match(uint32_t state, odd_even_t odd_even)
                        uint32_t *p = find_first_state(state, mask, &statelist_bitflip, 0);
                        if (p != NULL) {
                                while ((state & mask) == (*p & mask) && (*p != 0xffffffff)) {
                        uint32_t *p = find_first_state(state, mask, &statelist_bitflip, 0);
                        if (p != NULL) {
                                while ((state & mask) == (*p & mask) && (*p != 0xffffffff)) {

-                                       if (remaining_bits_match(j, best_first_bytes[0], i, state, (state&0x00fffff0) | *p, odd_even)) {
+                                       if (remaining_bits_match(j, bytes_diff, state, (state&0x00fffff0) | *p, odd_even)) {

                                                found_match = true;
                                                // if ((odd_even == ODD_STATE && state == test_state_odd)
                                                        // || (odd_even == EVEN_STATE && state == test_state_even)) {
                                                found_match = true;
                                                // if ((odd_even == ODD_STATE && state == test_state_odd)
                                                        // || (odd_even == EVEN_STATE && state == test_state_even)) {


@@ -1001,27 +1021,54 @@ static bool all_bit_flips_match(uint32_t state, odd_even_t odd_even)
 }
 
 
 }
 
 

-#define INVALID_BIT (1<<30)
-#define SET_INVALID(pstate) (*(pstate) |= INVALID_BIT)
-#define IS_INVALID(state) (state & INVALID_BIT)
+static struct sl_cache_entry {
+       uint32_t *sl;
+       uint32_t len;
+       } sl_cache[17][17][2];
+
+
+static void init_statelist_cache(void)
+{
+
+       for (uint16_t i = 0; i < 17; i+=2) {
+               for (uint16_t j = 0; j < 17; j+=2) {
+                       for (uint16_t k = 0; k < 2; k++) {
+                               sl_cache[i][j][k].sl = NULL;
+                               sl_cache[i][j][k].len = 0;
+                       }
+               }
+       }               
+}
+

 
 static int add_matching_states(statelist_t *candidates, uint16_t part_sum_a0, uint16_t part_sum_a8, odd_even_t odd_even)
 {
        uint32_t worstcase_size = 1<<20;
        
 
 static int add_matching_states(statelist_t *candidates, uint16_t part_sum_a0, uint16_t part_sum_a8, odd_even_t odd_even)
 {
        uint32_t worstcase_size = 1<<20;
        

+       // check cache for existing results
+       if (sl_cache[part_sum_a0][part_sum_a8][odd_even].sl != NULL) {
+               candidates->states[odd_even] = sl_cache[part_sum_a0][part_sum_a8][odd_even].sl;
+               candidates->len[odd_even] = sl_cache[part_sum_a0][part_sum_a8][odd_even].len;
+               return 0;
+       }
+       

        candidates->states[odd_even] = (uint32_t *)malloc(sizeof(uint32_t) * worstcase_size);
        if (candidates->states[odd_even] == NULL) {
                PrintAndLog("Out of memory error.\n");
                return 4;
        }
        candidates->states[odd_even] = (uint32_t *)malloc(sizeof(uint32_t) * worstcase_size);
        if (candidates->states[odd_even] == NULL) {
                PrintAndLog("Out of memory error.\n");
                return 4;
        }

+       uint32_t *add_p = candidates->states[odd_even]; 

        for (uint32_t *p1 = partial_statelist[part_sum_a0].states[odd_even]; *p1 != 0xffffffff; p1++) {
                uint32_t search_mask = 0x000ffff0;
                uint32_t *p2 = find_first_state((*p1 << 4), search_mask, &partial_statelist[part_sum_a8], odd_even);
                if (p2 != NULL) {
                        while (((*p1 << 4) & search_mask) == (*p2 & search_mask) && *p2 != 0xffffffff) {
        for (uint32_t *p1 = partial_statelist[part_sum_a0].states[odd_even]; *p1 != 0xffffffff; p1++) {
                uint32_t search_mask = 0x000ffff0;
                uint32_t *p2 = find_first_state((*p1 << 4), search_mask, &partial_statelist[part_sum_a8], odd_even);
                if (p2 != NULL) {
                        while (((*p1 << 4) & search_mask) == (*p2 & search_mask) && *p2 != 0xffffffff) {

+                               if ((nonces[best_first_bytes[0]].BitFlip[odd_even] && find_first_state((*p1 << 4) | *p2, 0x000fffff, &statelist_bitflip, 0))
+                                       || !nonces[best_first_bytes[0]].BitFlip[odd_even]) {

                                if (all_other_first_bytes_match((*p1 << 4) | *p2, odd_even)) {
                                        if (all_bit_flips_match((*p1 << 4) | *p2, odd_even)) { 
                                if (all_other_first_bytes_match((*p1 << 4) | *p2, odd_even)) {
                                        if (all_bit_flips_match((*p1 << 4) | *p2, odd_even)) { 

-                                       add_state(candidates, (*p1 << 4) | *p2, odd_even);
+                                                       *add_p++ = (*p1 << 4) | *p2;
+                                               }

                                }
                                }
                                p2++;
                                }
                                }
                                p2++;


@@ -1029,13 +1076,15 @@ static int add_matching_states(statelist_t *candidates, uint16_t part_sum_a0, ui
                }
        }
 
                }
        }
 

-       // set end of list marker
-       uint32_t *p = candidates->states[odd_even];
-       p += candidates->len[odd_even];
-       *p = 0xffffffff;
+       // set end of list marker and len
+       *add_p = 0xffffffff; 
+       candidates->len[odd_even] = add_p - candidates->states[odd_even];

 
        candidates->states[odd_even] = realloc(candidates->states[odd_even], sizeof(uint32_t) * (candidates->len[odd_even] + 1));
 
 
        candidates->states[odd_even] = realloc(candidates->states[odd_even], sizeof(uint32_t) * (candidates->len[odd_even] + 1));
 

+       sl_cache[part_sum_a0][part_sum_a8][odd_even].sl = candidates->states[odd_even];
+       sl_cache[part_sum_a0][part_sum_a8][odd_even].len = candidates->len[odd_even];
+

        return 0;
 }
 
        return 0;
 }
 


@@ -1094,7 +1143,7 @@ static void TestIfKeyExists(uint64_t key)
                        PrintAndLog("Key Found after testing %lld (2^%1.1f) out of %lld (2^%1.1f) keys. A brute force would have taken approx %lld minutes.", 
                                count, log(count)/log(2), 
                                maximum_states, log(maximum_states)/log(2),
                        PrintAndLog("Key Found after testing %lld (2^%1.1f) out of %lld (2^%1.1f) keys. A brute force would have taken approx %lld minutes.", 
                                count, log(count)/log(2), 
                                maximum_states, log(maximum_states)/log(2),

-                               (count>>22)/60);
+                               (count>>23)/60);

                        crypto1_destroy(pcs);
                        return;
                }
                        crypto1_destroy(pcs);
                        return;
                }


@@ -1121,6 +1170,8 @@ static void generate_candidates(uint16_t sum_a0, uint16_t sum_a8)
        }
        printf("Number of possible keys with Sum(a0) = %d: %lld (2^%1.1f)\n", sum_a0, maximum_states, log(maximum_states)/log(2.0));
        
        }
        printf("Number of possible keys with Sum(a0) = %d: %lld (2^%1.1f)\n", sum_a0, maximum_states, log(maximum_states)/log(2.0));
        

+       init_statelist_cache();
+       

        for (uint16_t p = 0; p <= 16; p += 2) {
                for (uint16_t q = 0; q <= 16; q += 2) {
                        if (p*(16-q) + (16-p)*q == sum_a0) {
        for (uint16_t p = 0; p <= 16; p += 2) {
                for (uint16_t q = 0; q <= 16; q += 2) {
                        if (p*(16-q) + (16-p)*q == sum_a0) {


@@ -1130,10 +1181,30 @@ static void generate_candidates(uint16_t sum_a0, uint16_t sum_a8)
                                        for (uint16_t s = 0; s <= 16; s += 2) {
                                                if (r*(16-s) + (16-r)*s == sum_a8) {
                                                        current_candidates = add_more_candidates(current_candidates);
                                        for (uint16_t s = 0; s <= 16; s += 2) {
                                                if (r*(16-s) + (16-r)*s == sum_a8) {
                                                        current_candidates = add_more_candidates(current_candidates);

+                                                       // check for the smallest partial statelist. Try this first - it might give 0 candidates 
+                                                       // and eliminate the need to calculate the other part
+                                                       if (MIN(partial_statelist[p].len[ODD_STATE], partial_statelist[r].len[ODD_STATE]) 
+                                                                       < MIN(partial_statelist[q].len[EVEN_STATE], partial_statelist[s].len[EVEN_STATE])) { 

                                                        add_matching_states(current_candidates, p, r, ODD_STATE);
                                                        add_matching_states(current_candidates, p, r, ODD_STATE);

-                                                       printf("Odd state candidates: %d (2^%0.1f)\n", current_candidates->len[ODD_STATE], log(current_candidates->len[ODD_STATE])/log(2)); 
+                                                               if(current_candidates->len[ODD_STATE]) {

                                                        add_matching_states(current_candidates, q, s, EVEN_STATE);
                                                        add_matching_states(current_candidates, q, s, EVEN_STATE);

-                                                       printf("Even state candidates: %d (2^%0.1f)\n", current_candidates->len[EVEN_STATE], log(current_candidates->len[EVEN_STATE])/log(2)); 
+                                                               } else {
+                                                                       current_candidates->len[EVEN_STATE] = 0;
+                                                                       uint32_t *p = current_candidates->states[EVEN_STATE] = malloc(sizeof(uint32_t));
+                                                                       *p = 0xffffffff;
+                                                               }
+                                                       } else {
+                                                               add_matching_states(current_candidates, q, s, EVEN_STATE);
+                                                               if(current_candidates->len[EVEN_STATE]) {
+                                                                       add_matching_states(current_candidates, p, r, ODD_STATE);
+                                                               } else {
+                                                                       current_candidates->len[ODD_STATE] = 0;
+                                                                       uint32_t *p = current_candidates->states[ODD_STATE] = malloc(sizeof(uint32_t));
+                                                                       *p = 0xffffffff;
+                                                               }
+                                                       }
+                                                       printf("Odd  state candidates: %6d (2^%0.1f)\n", current_candidates->len[ODD_STATE], log(current_candidates->len[ODD_STATE])/log(2)); 
+                                                       printf("Even state candidates: %6d (2^%0.1f)\n", current_candidates->len[EVEN_STATE], log(current_candidates->len[EVEN_STATE])/log(2)); 

                                                }
                                        }
                                }
                                                }
                                        }
                                }


@@ -1151,40 +1222,14 @@ static void generate_candidates(uint16_t sum_a0, uint16_t sum_a8)
 }
 
 
 }
 
 

-static void Check_for_FilterFlipProperties(void)
-{
-       printf("Checking for Filter Flip Properties...\n");
-
-       for (uint16_t i = 0; i < 256; i++) {
-               nonces[i].BitFlip[ODD_STATE] = false;
-               nonces[i].BitFlip[EVEN_STATE] = false;
-       }
-       
-       for (uint16_t i = 0; i < 256; i++) {
-               uint8_t parity1 = (nonces[i].first->par_enc) >> 3;                              // parity of first byte
-               uint8_t parity2_odd = (nonces[i^0x80].first->par_enc) >> 3;     // XOR 0x80 = last bit flipped
-               uint8_t parity2_even = (nonces[i^0x40].first->par_enc) >> 3;    // XOR 0x40 = second last bit flipped
-               
-               if (parity1 == parity2_odd) {                           // has Bit Flip Property for odd bits
-                       nonces[i].BitFlip[ODD_STATE] = true;
-               } else if (parity1 == parity2_even) {           // has Bit Flip Property for even bits
-                       nonces[i].BitFlip[EVEN_STATE] = true;
-               }
-       }
-}
-
-

 static void brute_force(void)
 {
        if (known_target_key != -1) {
                PrintAndLog("Looking for known target key in remaining key space...");
                TestIfKeyExists(known_target_key);
 static void brute_force(void)
 {
        if (known_target_key != -1) {
                PrintAndLog("Looking for known target key in remaining key space...");
                TestIfKeyExists(known_target_key);

-               return;

        } else {
                PrintAndLog("Brute Force phase is not implemented.");
        } else {
                PrintAndLog("Brute Force phase is not implemented.");

-               return;

        }
        }

-       

 
 }
 
 
 }
 


@@ -1217,6 +1262,7 @@ int mfnestedhard(uint8_t blockNo, uint8_t keyType, uint8_t *key, uint8_t trgBloc
                if (read_nonce_file() != 0) {
                        return 3;
                }
                if (read_nonce_file() != 0) {
                        return 3;
                }

+               Check_for_FilterFlipProperties();

                num_good_first_bytes = MIN(estimate_second_byte_sum(), GOOD_BYTES_REQUIRED);
        } else {                                        // acquire nonces.
                uint16_t is_OK = acquire_nonces(blockNo, keyType, key, trgBlockNo, trgKeyType, nonce_file_write, slow);
                num_good_first_bytes = MIN(estimate_second_byte_sum(), GOOD_BYTES_REQUIRED);
        } else {                                        // acquire nonces.
                uint16_t is_OK = acquire_nonces(blockNo, keyType, key, trgBlockNo, trgKeyType, nonce_file_write, slow);


@@ -1225,7 +1271,6 @@ int mfnestedhard(uint8_t blockNo, uint8_t keyType, uint8_t *key, uint8_t trgBloc
                }
        }
 
                }
        }
 

-       Check_for_FilterFlipProperties();

 
        Tests();
 
 
        Tests();
 


@@ -1244,7 +1289,9 @@ int mfnestedhard(uint8_t blockNo, uint8_t keyType, uint8_t *key, uint8_t trgBloc
                // best_first_bytes[9]  );
        PrintAndLog("Number of first bytes with confidence > %2.1f%%: %d", CONFIDENCE_THRESHOLD*100.0, num_good_first_bytes);
 
                // best_first_bytes[9]  );
        PrintAndLog("Number of first bytes with confidence > %2.1f%%: %d", CONFIDENCE_THRESHOLD*100.0, num_good_first_bytes);
 

+       time_t start_time = clock();

        generate_candidates(first_byte_Sum, nonces[best_first_bytes[0]].Sum8_guess);
        generate_candidates(first_byte_Sum, nonces[best_first_bytes[0]].Sum8_guess);

+       PrintAndLog("Time for generating key candidates list: %1.0f seconds", (float)(clock() - start_time)/CLOCKS_PER_SEC);

        
        brute_force();
        
        
        brute_force();