cryptopals/ex04/main.c
2020-06-03 21:20:38 +02:00

63 lines
1.4 KiB
C

#include "utils.h"
#include <ctype.h>
#include <stdio.h>
int main(int argc, char *argv[]) {
if (argc < 2) {
printf("Usage: %s <filename>\n", argv[0]);
return EXIT_FAILURE;
}
FILE *fp = fopen(argv[1], "r");
if (fp == NULL) {
printf("Error opening file %s\n", argv[1]);
return EXIT_FAILURE;
}
printf("line | key | score | cleartext\n");
printf("-----+-----+-------+-------------------------------\n");
unsigned int line_count = 0;
char *line = NULL;
size_t line_length = 0;
ssize_t nread = 0;
size_t len;
while ((nread = getline(&line, &line_length, fp)) != -1) {
line_count++;
line[60] = '\0';
// printf("%3u: %s\n", line_count, line);
unsigned char buf[512] = {0};
len = hex_to_bytes(buf, line);
unsigned char cur[512] = {'\0'};
for (char c = 32; c < 127; ++c) {
for (size_t i = 0; i < len; ++i) {
cur[i] = buf[i] ^ c;
}
double score = frequency_score(cur, len);
if (score < 40.0) {
printf("%4u | %c | %5.1f | ", line_count, c,
score);
for (size_t i = 0; i < len; ++i) {
if (isprint(cur[i])) {
putchar(cur[i]);
} else if (cur[i] == '\n') {
printf("\\n");
}
}
printf("\n");
}
}
}
free(line);
if (fclose(fp)) {
printf("Error closing file %s\n", argv[1]);
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}