int main()
{
const char * input = "Burning 'em, if you ain't quick and nimble\n"
"I go crazy when I hear a cymbal";
size_t input_size = strlen(input);
const char * key = "ICE";
size_t key_size = strlen(key);
size_t output_max_size = 148;
char output[output_max_size];
size_t output_used_size = repeating_key_xor(input,
input_size,
key, key_size,
output,
output_max_size);
if (output_used_size != 0) {
for (size_t i = 0; i < output_used_size; ++i) {
printf("%c", output[i]);
}
printf("\n");
return 0;
}
else {
return 1;
}
}
void break_repeating_key_xor(const unsigned char *in, size_t in_len,
unsigned char *key, size_t key_max_len, unsigned int *key_len,
unsigned char *out)
{
unsigned int i, j;
unsigned int base_limit, limit, leftover;
unsigned char *buf;
*key_len = get_key_len(in, in_len, key_max_len);
base_limit = in_len / *key_len;
leftover = in_len % *key_len;
buf = malloc(base_limit + !!leftover);
if (!buf)
exit(1);
for (i = 0; i < *key_len; i++) {
limit = base_limit + (leftover > i);
for (j = 0; j < limit; j++)
out[j] = in[j * *key_len + i];
key[i] = crack_single_byte_xor(out, limit, buf);
}
free(buf);
repeating_key_xor(in, in_len, key, *key_len, out);
}
