+//-----------------------------------------------------------------------------
+// Copyright (C) 2015, 2016 by piwi
+//
+// This code is licensed to you under the terms of the GNU GPL, version 2 or,
+// at your option, any later version. See the LICENSE.txt file for the text of
+// the license.
+//-----------------------------------------------------------------------------
+// Implements a card only attack based on crypto text (encrypted nonces
+// received during a nested authentication) only. Unlike other card only
+// attacks this doesn't rely on implementation errors but only on the
+// inherent weaknesses of the crypto1 cypher. Described in
+// Carlo Meijer, Roel Verdult, "Ciphertext-only Cryptanalysis on Hardened
+// Mifare Classic Cards" in Proceedings of the 22nd ACM SIGSAC Conference on
+// Computer and Communications Security, 2015
+//-----------------------------------------------------------------------------
+//
+// This program calculates tables with possible states for a given
+// bitflip property.
+//
+//-----------------------------------------------------------------------------
+
+#include <inttypes.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <time.h>
+#include "crapto1/crapto1.h"
+#include "parity.h"
+
+
+#define NUM_PART_SUMS 9
+#define BITFLIP_2ND_BYTE 0x0200
+
+typedef enum {
+ EVEN_STATE = 0,
+ ODD_STATE = 1
+} odd_even_t;
+
+
+static uint16_t PartialSumProperty(uint32_t state, odd_even_t odd_even)
+{
+ uint16_t sum = 0;
+ for (uint16_t j = 0; j < 16; j++) {
+ uint32_t st = state;
+ uint16_t part_sum = 0;
+ if (odd_even == ODD_STATE) {
+ for (uint16_t i = 0; i < 5; i++) {
+ part_sum ^= filter(st);
+ st = (st << 1) | ((j >> (3-i)) & 0x01) ;
+ }
+ part_sum ^= 1; // XOR 1 cancelled out for the other 8 bits
+ } else {
+ for (uint16_t i = 0; i < 4; i++) {
+ st = (st << 1) | ((j >> (3-i)) & 0x01) ;
+ part_sum ^= filter(st);
+ }
+ }
+ sum += part_sum;
+ }
+ return sum;
+}
+
+
+//////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+// bitarray functions
+
+#define malloc_bitarray(x) __builtin_assume_aligned(_aligned_malloc(x, __BIGGEST_ALIGNMENT__), __BIGGEST_ALIGNMENT__)
+#define free_bitarray(x) _aligned_free(x)
+
+static inline void clear_bitarray24(uint32_t *bitarray)
+{
+ memset(bitarray, 0x00, sizeof(uint32_t) * (1<<19));
+}
+
+
+static inline uint32_t test_bit24(uint32_t *bitarray, uint32_t index)
+{
+ return bitarray[index>>5] & (0x80000000>>(index&0x0000001f));
+}
+
+
+static inline void set_bit24(uint32_t *bitarray, uint32_t index)
+{
+ bitarray[index>>5] |= 0x80000000>>(index&0x0000001f);
+}
+
+
+static inline uint32_t next_state(uint32_t *bitset, uint32_t state)
+{
+ if (++state == 1<<24) return 1<<24;
+ uint32_t index = state >> 5;
+ uint_fast8_t bit = state & 0x1f;
+ uint32_t line = bitset[index] << bit;
+ while (bit <= 0x1f) {
+ if (line & 0x80000000) return state;
+ state++;
+ bit++;
+ line <<= 1;
+ }
+ index++;
+ while (bitset[index] == 0x00000000 && state < 1<<24) {
+ index++;
+ state += 0x20;
+ }
+ if (state >= 1<<24) return 1<<24;
+#if defined __GNUC__
+ return state + __builtin_clz(bitset[index]);
+#else
+ bit = 0x00;
+ line = bitset[index];
+ while (bit <= 0x1f) {
+ if (line & 0x80000000) return state;
+ state++;
+ bit++;
+ line <<= 1;
+ }
+ return 1<<24;
+#endif
+}
+
+
+static inline uint32_t next_not_state(uint32_t *bitset, uint32_t state)
+{
+ if (++state == 1<<24) return 1<<24;
+ uint32_t index = state >> 5;
+ uint_fast8_t bit = state & 0x1f;
+ uint32_t line = bitset[index] << bit;
+ while (bit <= 0x1f) {
+ if ((line & 0x80000000) == 0) return state;
+ state++;
+ bit++;
+ line <<= 1;
+ }
+ index++;
+ while (bitset[index] == 0xffffffff && state < 1<<24) {
+ index++;
+ state += 0x20;
+ }
+ if (state >= 1<<24) return 1<<24;
+#if defined __GNUC__
+ return state + __builtin_clz(~bitset[index]);
+#else
+ bit = 0x00;
+ line = bitset[index];
+ while (bit <= 0x1f) {
+ if ((line & 0x80000000) == 0) return state;
+ state++;
+ bit++;
+ line <<= 1;
+ }
+ return 1<<24;
+#endif
+}
+
+
+static inline uint32_t bitcount(uint32_t a)
+{
+#if defined __GNUC__
+ return __builtin_popcountl(a);
+#else
+ a = a - ((a >> 1) & 0x55555555);
+ a = (a & 0x33333333) + ((a >> 2) & 0x33333333);
+ return (((a + (a >> 4)) & 0x0f0f0f0f) * 0x01010101) >> 24;
+#endif
+}
+
+
+static inline uint32_t count_states(uint32_t *bitset)
+{
+ uint32_t count = 0;
+ for (uint32_t i = 0; i < (1<<19); i++) {
+ count += bitcount(bitset[i]);
+ }
+ return count;
+}
+
+
+static void write_bitflips_file(odd_even_t odd_even, uint16_t bitflip, int sum_a0, uint32_t *bitset)
+{
+ char filename[80];
+ sprintf(filename, "bitflip_%d_%03" PRIx16 "_sum%d_states.bin", odd_even, bitflip, sum_a0);
+ FILE *outfile = fopen(filename, "wb");
+ fwrite(bitset, 1, sizeof(uint32_t)*(1<<19), outfile);
+ fclose(outfile);
+}
+
+
+uint32_t *restrict part_sum_a0_bitarrays[2][NUM_PART_SUMS];
+
+static void init_part_sum_bitarrays(void)
+{
+ printf("init_part_sum_bitarrays()...");
+ for (odd_even_t odd_even = EVEN_STATE; odd_even <= ODD_STATE; odd_even++) {
+ for (uint16_t part_sum_a0 = 0; part_sum_a0 < NUM_PART_SUMS; part_sum_a0++) {
+ part_sum_a0_bitarrays[odd_even][part_sum_a0] = (uint32_t *)malloc_bitarray(sizeof(uint32_t) * (1<<19));
+ if (part_sum_a0_bitarrays[odd_even][part_sum_a0] == NULL) {
+ printf("Out of memory error in init_part_suma0_statelists(). Aborting...\n");
+ exit(4);
+ }
+ clear_bitarray24(part_sum_a0_bitarrays[odd_even][part_sum_a0]);
+ }
+ }
+ for (odd_even_t odd_even = EVEN_STATE; odd_even <= ODD_STATE; odd_even++) {
+ //printf("(%d, %" PRIu16 ")...", odd_even, part_sum_a0);
+ for (uint32_t state = 0; state < (1<<20); state++) {
+ uint16_t part_sum_a0 = PartialSumProperty(state, odd_even) / 2;
+ for (uint16_t low_bits = 0; low_bits < 1<<4; low_bits++) {
+ set_bit24(part_sum_a0_bitarrays[odd_even][part_sum_a0], state<<4 | low_bits);
+ }
+ }
+ }
+ printf("done.\n");
+}
+
+
+static void free_part_sum_bitarrays(void)
+{
+ printf("free_part_sum_bitarrays()...");
+ for (int16_t part_sum_a0 = (NUM_PART_SUMS-1); part_sum_a0 >= 0; part_sum_a0--) {
+ free_bitarray(part_sum_a0_bitarrays[ODD_STATE][part_sum_a0]);
+ }
+ for (int16_t part_sum_a0 = (NUM_PART_SUMS-1); part_sum_a0 >= 0; part_sum_a0--) {
+ free_bitarray(part_sum_a0_bitarrays[EVEN_STATE][part_sum_a0]);
+ }
+ printf("done.\n");
+}
+
+uint32_t *restrict sum_a0_bitarray[2];
+
+void init_sum_bitarray(uint16_t sum_a0)
+{
+ printf("init_sum_bitarray()...\n");
+ for (odd_even_t odd_even = EVEN_STATE; odd_even <= ODD_STATE; odd_even++) {
+ sum_a0_bitarray[odd_even] = (uint32_t *)malloc_bitarray(sizeof(uint32_t) * (1<<19));
+ if (sum_a0_bitarray[odd_even] == NULL) {
+ printf("Out of memory error in init_sum_bitarrays(). Aborting...\n");
+ exit(4);
+ }
+ clear_bitarray24(sum_a0_bitarray[odd_even]);
+ }
+ for (uint8_t p = 0; p < NUM_PART_SUMS; p++) {
+ for (uint8_t q = 0; q < NUM_PART_SUMS; q++) {
+ if (sum_a0 == 2*p*(16-2*q) + (16-2*p)*2*q) {
+ for (uint32_t i = 0; i < (1<<19); i++) {
+ sum_a0_bitarray[EVEN_STATE][i] |= part_sum_a0_bitarrays[EVEN_STATE][q][i];
+ sum_a0_bitarray[ODD_STATE][i] |= part_sum_a0_bitarrays[ODD_STATE][p][i];
+ }
+ }
+ }
+ }
+ for (odd_even_t odd_even = EVEN_STATE; odd_even <= ODD_STATE; odd_even++) {
+ uint32_t count = count_states(sum_a0_bitarray[odd_even]);
+ printf("sum_a0_bitarray[%s] has %d states (%5.2f%%)\n", odd_even==EVEN_STATE?"even":"odd ", count, (float)count/(1<<24)*100.0);
+ }
+ printf("done.\n");
+}
+
+
+static void free_sum_bitarray(void)
+{
+ printf("free_sum_bitarray()...");
+ free_bitarray(sum_a0_bitarray[ODD_STATE]);
+ free_bitarray(sum_a0_bitarray[EVEN_STATE]);
+ printf("done.\n");
+}
+
+
+static void precalculate_bit0_bitflip_bitarrays(uint8_t const bitflip, uint16_t const sum_a0)
+{
+ // #define TEST_RUN
+ #ifdef TEST_RUN
+ #define NUM_TEST_STATES (1<<10)
+ #else
+ #define NUM_TEST_STATES (1<<23)
+ #endif
+
+ time_t start_time = time(NULL);
+ time_t last_check_time = start_time;
+
+ uint32_t *restrict test_bitarray[2];
+ uint32_t *restrict test_not_bitarray[2];
+
+ test_bitarray[EVEN_STATE] = malloc_bitarray(sizeof(uint32_t) * (1<<19));
+ clear_bitarray24(test_bitarray[EVEN_STATE]);
+ test_bitarray[ODD_STATE] = malloc_bitarray(sizeof(uint32_t) * (1<<19));
+ clear_bitarray24(test_bitarray[ODD_STATE]);
+
+ test_not_bitarray[EVEN_STATE] = malloc_bitarray(sizeof(uint32_t) * (1<<19));
+ clear_bitarray24(test_not_bitarray[EVEN_STATE]);
+ test_not_bitarray[ODD_STATE] = malloc_bitarray(sizeof(uint32_t) * (1<<19));
+ clear_bitarray24(test_not_bitarray[ODD_STATE]);
+
+ uint32_t count[2];
+ bool all_odd_states_are_possible_for_notbitflip = false;
+
+ printf("\n\nStarting search for crypto1 states resulting in bitflip property 0x%03x...\n", bitflip);
+ for (uint32_t even_state = next_state(sum_a0_bitarray[EVEN_STATE], -1); even_state < NUM_TEST_STATES; even_state = next_state(sum_a0_bitarray[EVEN_STATE], even_state)) {
+ bool even_state_is_possible = false;
+ time_t time_now = time(NULL);
+ if (difftime(time_now, last_check_time) > 5*60) { // print status every 5 minutes
+ float runtime = difftime(time_now, start_time);
+ float remaining_time = runtime * ((1<<23) - even_state) / even_state;
+ printf("\n%1.1f hours elapsed, expected completion in %1.1f hours (%1.1f days)", runtime/3600, remaining_time/3600, remaining_time/3600/24);
+ last_check_time = time_now;
+ }
+ for (uint32_t odd_state = next_state(sum_a0_bitarray[ODD_STATE], -1); odd_state < (1<<24); odd_state = next_state(test_bitarray[ODD_STATE], odd_state)) {
+ if (even_state_is_possible && test_bit24(test_bitarray[ODD_STATE], odd_state)) continue;
+ // load crypto1 state
+ struct Crypto1State cs;
+ cs.odd = odd_state >> 4;
+ cs.even = even_state >> 4;
+
+ // track flipping bits in state
+ struct Crypto1DeltaState {
+ uint_fast8_t odd;
+ uint_fast8_t even;
+ } cs_delta;
+ cs_delta.odd = 0;
+ cs_delta.even = 0;
+
+ uint_fast16_t keystream = 0;
+
+ // decrypt 9 bits
+ for (int i = 0; i < 9; i++) {
+ uint_fast8_t keystream_bit = filter(cs.odd & 0x000fffff) ^ filter((cs.odd & 0x000fffff) ^ cs_delta.odd);
+ keystream = keystream << 1 | keystream_bit;
+ uint_fast8_t nt_bit = BIT(bitflip, i) ^ keystream_bit;
+ uint_fast8_t LSFR_feedback = BIT(cs_delta.odd, 2) ^ BIT(cs_delta.even, 2) ^ BIT(cs_delta.odd, 3);
+
+ cs_delta.even = cs_delta.even << 1 | (LSFR_feedback ^ nt_bit);
+ uint_fast8_t tmp = cs_delta.odd;
+ cs_delta.odd = cs_delta.even;
+ cs_delta.even = tmp;
+
+ cs.even = cs.odd;
+ if (i & 1) {
+ cs.odd = odd_state >> (7 - i) / 2;
+ } else {
+ cs.odd = even_state >> (7 - i) / 2;
+ }
+ }
+
+ if (evenparity32(keystream) == evenparity32(bitflip)) {
+ // found valid bitflip state
+ even_state_is_possible = true;
+ set_bit24(test_bitarray[EVEN_STATE], even_state);
+ set_bit24(test_bitarray[EVEN_STATE], 1 << 23 | even_state);
+ set_bit24(test_bitarray[ODD_STATE], odd_state);
+ } else {
+ // found valid !bitflip state
+ set_bit24(test_not_bitarray[EVEN_STATE], even_state);
+ set_bit24(test_not_bitarray[EVEN_STATE], 1 << 23 | even_state);
+ set_bit24(test_not_bitarray[ODD_STATE], odd_state);
+ }
+ }
+ if (!even_state_is_possible) {
+ all_odd_states_are_possible_for_notbitflip = true;
+ }
+ }
+
+ printf("\nAnalysis completed. Checking for effective bitflip properties...\n");
+ for (odd_even_t odd_even = EVEN_STATE; odd_even <= ODD_STATE; odd_even++) {
+ count[odd_even] = count_states(test_bitarray[odd_even]);
+ if (count[odd_even] != 1<<24) {
+ printf("Writing %d possible %s states for bitflip property %03x (%d (%1.2f%%) states eliminated)\n",
+ count[odd_even],
+ odd_even==EVEN_STATE?"even":"odd",
+ bitflip, (1<<24) - count[odd_even],
+ (float)((1<<24) - count[odd_even]) / (1<<24) * 100.0);
+ #ifndef TEST_RUN
+ write_bitflips_file(odd_even, bitflip, sum_a0, test_bitarray[odd_even]);
+ #endif
+ } else {
+ printf("All %s states for bitflip property %03x are possible. No file written.\n", odd_even==EVEN_STATE?"even":"odd", bitflip);
+ }
+ }
+ uint32_t *restrict test_bitarray_2nd = malloc_bitarray(sizeof(uint32_t) * (1<<19));
+ clear_bitarray24(test_bitarray_2nd);
+ for (odd_even_t odd_even = EVEN_STATE; odd_even <= ODD_STATE; odd_even++) {
+ if (count[odd_even] != 1<<24) {
+ for (uint32_t state = 0; state < (1<<24); state += 1<<4) {
+ uint32_t line = test_bitarray[odd_even][state>>5];
+ uint16_t half_line = state&0x000000010 ? line&0x0000ffff : line>>16;
+ if (half_line != 0) {
+ for (uint32_t low_bits = 0; low_bits < (1<<4); low_bits++) {
+ set_bit24(test_bitarray_2nd, low_bits << 20 | state >> 4);
+ }
+ }
+ }
+ count[odd_even] = count_states(test_bitarray_2nd);
+ if (count[odd_even] != 1<<24) {
+ printf("Writing %d possible %s states for bitflip property %03x (%d (%1.2f%%) states eliminated)\n",
+ count[odd_even],
+ odd_even==EVEN_STATE?"even":"odd",
+ bitflip | BITFLIP_2ND_BYTE, (1<<24) - count[odd_even],
+ (float)((1<<24) - count[odd_even]) / (1<<24) * 100.0);
+ #ifndef TEST_RUN
+ write_bitflips_file(odd_even, bitflip | BITFLIP_2ND_BYTE, sum_a0, test_bitarray_2nd);
+ #endif
+ } else {
+ printf("All %s states for bitflip property %03x are possible. No file written.\n", odd_even==EVEN_STATE?"even":"odd", bitflip | BITFLIP_2ND_BYTE);
+ }
+ } else {
+ printf("All %s states for bitflip property %03x are possible. No file written.\n", odd_even==EVEN_STATE?"even":"odd", bitflip | BITFLIP_2ND_BYTE);
+ }
+ }
+
+ ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+ // second run for the remaining "not bitflip" states
+ printf("\n\nStarting search for crypto1 states resulting in bitflip property 0x%03x...", bitflip | 0x100);
+ start_time = time(NULL);
+ last_check_time = start_time;
+ for (uint32_t even_state = next_state(sum_a0_bitarray[EVEN_STATE], -1); even_state < NUM_TEST_STATES; even_state = next_state(sum_a0_bitarray[EVEN_STATE], even_state)) {
+ bool even_state_is_possible = test_bit24(test_not_bitarray[EVEN_STATE], even_state);
+ time_t time_now = time(NULL);
+ if (difftime(time_now, last_check_time) > 5*60) { // print status every 5 minutes
+ float runtime = difftime(time_now, start_time);
+ float remaining_time = runtime * ((1<<23) - even_state) / even_state;
+ printf("\n%1.1f hours elapsed, expected completion in %1.1f hours (%1.1f days)", runtime/3600, remaining_time/3600, remaining_time/3600/24);
+ last_check_time = time_now;
+ }
+ for (uint32_t odd_state = next_state(sum_a0_bitarray[ODD_STATE], -1); odd_state < (1<<24); odd_state = next_state(sum_a0_bitarray[ODD_STATE], odd_state)) {
+ if (even_state_is_possible) {
+ if (all_odd_states_are_possible_for_notbitflip) break;
+ if (test_bit24(test_not_bitarray[ODD_STATE], odd_state)) continue;
+ }
+ // load crypto1 state
+ struct Crypto1State cs;
+ cs.odd = odd_state >> 4;
+ cs.even = even_state >> 4;
+
+ // track flipping bits in state
+ struct Crypto1DeltaState {
+ uint_fast8_t odd;
+ uint_fast8_t even;
+ } cs_delta;
+ cs_delta.odd = 0;
+ cs_delta.even = 0;
+
+ uint_fast16_t keystream = 0;
+ // uint_fast16_t nt = 0;
+
+ // decrypt 9 bits
+ for (int i = 0; i < 9; i++) {
+ uint_fast8_t keystream_bit = filter(cs.odd & 0x000fffff) ^ filter((cs.odd & 0x000fffff) ^ cs_delta.odd);
+ keystream = keystream << 1 | keystream_bit;
+ uint_fast8_t nt_bit = BIT(bitflip|0x100, i) ^ keystream_bit;
+ uint_fast8_t LSFR_feedback = BIT(cs_delta.odd, 2) ^ BIT(cs_delta.even, 2) ^ BIT(cs_delta.odd, 3);
+
+ cs_delta.even = cs_delta.even << 1 | (LSFR_feedback ^ nt_bit);
+ uint_fast8_t tmp = cs_delta.odd;
+ cs_delta.odd = cs_delta.even;
+ cs_delta.even = tmp;
+
+ cs.even = cs.odd;
+ if (i & 1) {
+ cs.odd = odd_state >> (7 - i) / 2;
+ } else {
+ cs.odd = even_state >> (7 - i) / 2;
+ }
+ }
+
+ if (evenparity32(keystream) != evenparity32(bitflip)) {
+ // found valid !bitflip state
+ even_state_is_possible = true;
+ set_bit24(test_not_bitarray[EVEN_STATE], even_state);
+ set_bit24(test_not_bitarray[EVEN_STATE], 1 << 23 | even_state);
+ set_bit24(test_not_bitarray[ODD_STATE], odd_state);
+ }
+ }
+ }
+
+ printf("\nAnalysis completed. Checking for effective !bitflip properties...\n");
+ for (odd_even_t odd_even = EVEN_STATE; odd_even <= ODD_STATE; odd_even++) {
+ count[odd_even] = count_states(test_not_bitarray[odd_even]);
+ if (count[odd_even] != 1<<24) {
+ printf("Writing %d possible %s states for bitflip property %03x (%d (%1.2f%%) states eliminated)\n",
+ count[odd_even],
+ odd_even==EVEN_STATE?"even":"odd",
+ bitflip|0x100, (1<<24) - count[odd_even],
+ (float)((1<<24) - count[odd_even]) / (1<<24) * 100.0);
+ #ifndef TEST_RUN
+ write_bitflips_file(odd_even, bitflip|0x100, sum_a0, test_not_bitarray[odd_even]);
+ #endif
+ } else {
+ printf("All %s states for bitflip property %03x are possible. No file written.\n", odd_even==EVEN_STATE?"even":"odd", bitflip|0x100);
+ }
+ }
+
+ clear_bitarray24(test_bitarray_2nd);
+ for (odd_even_t odd_even = EVEN_STATE; odd_even <= ODD_STATE; odd_even++) {
+ if (count[odd_even] != 1<<24) {
+ for (uint32_t state = 0; state < (1<<24); state += 1<<4) {
+ uint32_t line = test_not_bitarray[odd_even][state>>5];
+ uint16_t half_line = state&0x000000010 ? line&0x0000ffff : line>>16;
+ if (half_line != 0) {
+ for (uint32_t low_bits = 0; low_bits < (1<<4); low_bits++) {
+ set_bit24(test_bitarray_2nd, low_bits << 20 | state >> 4);
+ }
+ }
+ }
+ count[odd_even] = count_states(test_bitarray_2nd);
+ if (count[odd_even] != 1<<24) {
+ printf("Writing %d possible %s states for bitflip property %03x (%d (%1.2f%%) states eliminated)\n",
+ count[odd_even],
+ odd_even==EVEN_STATE?"even":"odd",
+ bitflip | 0x100| BITFLIP_2ND_BYTE, (1<<24) - count[odd_even],
+ (float)((1<<24) - count[odd_even]) / (1<<24) * 100.0);
+ #ifndef TEST_RUN
+ write_bitflips_file(odd_even, bitflip | 0x100 | BITFLIP_2ND_BYTE, sum_a0, test_bitarray_2nd);
+ #endif
+ } else {
+ printf("All %s states for bitflip property %03x are possible. No file written.\n", odd_even==EVEN_STATE?"even":"odd", bitflip | 0x100 | BITFLIP_2ND_BYTE);
+ }
+ } else {
+ printf("All %s states for bitflip property %03x are possible. No file written.\n", odd_even==EVEN_STATE?"even":"odd", bitflip | 0x100 | BITFLIP_2ND_BYTE);
+ }
+ }
+
+ free_bitarray(test_bitarray_2nd);
+ free_bitarray(test_not_bitarray[ODD_STATE]);
+ free_bitarray(test_not_bitarray[EVEN_STATE]);
+ free_bitarray(test_bitarray[ODD_STATE]);
+ free_bitarray(test_bitarray[EVEN_STATE]);
+
+ exit(0);
+}
+
+
+int main (int argc, char *argv[]) {
+
+ unsigned int bitflip_in;
+ int sum_a0;
+
+ printf("Create tables required by hardnested attack.\n");
+ printf("Expect a runtime in the range of days or weeks.\n");
+ printf("Single thread only. If you want to use several threads, start it multiple times :-)\n\n");
+
+ if (argc != 2 && argc != 3) {
+ printf(" syntax: %s <bitflip property> [<Sum_a0>]\n\n", argv[0]);
+ printf(" example: %s 1f\n", argv[0]);
+ return 1;
+ }
+
+ sscanf(argv[1],"%x", &bitflip_in);
+
+ if (bitflip_in > 255) {
+ printf("Bitflip property must be less than or equal to 0xff\n\n");
+ return 1;
+ }
+
+ if(argc == 3) {
+ sscanf(argv[2], "%d", &sum_a0);
+ }
+
+ switch (sum_a0) {
+ case 0:
+ case 32:
+ case 56:
+ case 64:
+ case 80:
+ case 96:
+ case 104:
+ case 112:
+ case 120:
+ case 128:
+ case 136:
+ case 144:
+ case 152:
+ case 160:
+ case 176:
+ case 192:
+ case 200:
+ case 224:
+ case 256: break;
+ default: sum_a0 = -1;
+ }
+
+ printf("Calculating for bitflip = %02x, sum_a0 = %d\n", bitflip_in, sum_a0);
+
+ init_part_sum_bitarrays();
+ init_sum_bitarray(sum_a0);
+
+ precalculate_bit0_bitflip_bitarrays(bitflip_in, sum_a0);
+
+ free_sum_bitarray();
+ free_part_sum_bitarrays();
+
+ return 0;
+}
\ No newline at end of file