diff options
| -rw-r--r-- | A5.1/C/calculate_chain.c | 34 |
1 files changed, 26 insertions, 8 deletions
diff --git a/A5.1/C/calculate_chain.c b/A5.1/C/calculate_chain.c index 5b6d18e..28aec0f 100644 --- a/A5.1/C/calculate_chain.c +++ b/A5.1/C/calculate_chain.c @@ -123,19 +123,37 @@ uint64 calculate_chain (uint64 input, uint32 count) { input = calculate_link(input, i); } return input; -} +} + +/* Linear congruential generator used to whiten start value. + * Numbers stolen from Lawrence Livermore National Laboratory RNG + * library: http://nuclear.llnl.gov/CNP/rng/rngman/node4.html + */ +uint64 start_value_from_index (uint64 count) { + return 2862933555777941757UL * (count + 1) + 3037000493L; +} + +void usage (char* argv[]) { + printf("Usage: %s <startvalue>\n\nSpecify the start value as 16 hex digits, or chain number as 10 hex digits. Calculates one\nchain of the A5/1 rainbow table, and outputs the end value.\n", argv[0]); + exit(1); +} int main(int argc, char* argv[]) { int i,j; uint64 current; - if (argc<2 || sscanf(argv[1], "%16lx", ¤t) != 1) { - printf("Usage: %s <startvalue>\n\nSpecify the start value as 16 hex digits. Calculates one\nchain of the A5/1 rainbow table, and outputs the end value.\n", argv[0]); - exit(1); + if (argc<2) { + usage(argv); + } else if (strlen(argv[1])==16 && sscanf(argv[1], "%16lx", ¤t) == 1) { + printf("Calculating chain from start value 0x%16.16lx\n", current); + current = calculate_chain(current, pow(2, 21)); + } else if (sscanf(argv[1], "%16lx", ¤t) == 1) { + current = start_value_from_index(current); + printf("Calculating chain from start value 0x%16.16lx\n", current); + current = calculate_chain(current, pow(2, 21)); + } else { + usage(argv); } - - current = calculate_chain(current, pow(2, 21)); - - printf("%16.16lx\n", current); + printf("End value: 0x%16.16lx\n", current); return 0; } |