154 lines
3.3 KiB
C
154 lines
3.3 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <getopt.h>
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#include <time.h>
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// Local includes
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#include "strenc.h"
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// Open file and return point to char containing file contents
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unsigned char *openFile(char *fileName, size_t *len) {
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size_t c = 0;
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size_t size = 8;
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unsigned char *buf = malloc(size);
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FILE *fp;
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fp = fopen(fileName, "r");
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for (size_t i = 0; (c = fgetc(fp)) != EOF; i++) {
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if (i == size) { // If size of current buffer need to be doubled
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size *= 2;
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buf = reallocarray(buf, size, sizeof(unsigned char));
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if (buf == NULL) {
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printf("Error resizing array, exiting...\n");
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exit(EXIT_FAILURE);
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}
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}
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buf[i] = c;
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len++;
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}
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fclose(fp);
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return buf;
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}
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unsigned char *genKey(unsigned char *pt, size_t len) {
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unsigned char *key = malloc(len);
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srand(time(NULL));
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// rand() should not normally be used for
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// generating secure numbers, we do not care
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// here
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for (int i = 0; i < len; i++) {
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key[i] = rand();
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}
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return key;
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}
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unsigned char *xorCharArray(unsigned char *text, unsigned char *key, size_t len) {
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unsigned char *ft = malloc(len);
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for (int i = 0; i < len; i++) { // Xor pt & key
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ft[i] = text[i] ^ key[i];
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}
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return ft;
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}
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int printCStyleCharArray(unsigned char *text, unsigned char *key, size_t len) {
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// Print text
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printf("unsigned char text[%zu] = { ", len);
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for (int i = 0; i < len; i++) {
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printf("0x%02X", text[i]);
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if ((i + 1) == len) {
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printf(" ");
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} else {
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printf(", ");
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}
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}
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printf("};\n");
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// Print key
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printf("unsigned char text_key[%zu] = { ", len);
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for (int i = 0; i < len; i++) {
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printf("0x%02X", key[i]);
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if ((i + 1) == len) {
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printf(" ");
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} else {
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printf(", ");
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}
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}
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printf("};\n");
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return 0;
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}
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int main(int argc, char **argv) {
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unsigned char *pt = NULL;
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unsigned char *key = NULL;
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unsigned char *ct = NULL;
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size_t pt_len = 0;
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// Setting up options
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static const struct option long_options[] = {
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{"help", no_argument, NULL, 'h'},
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{"file", required_argument, NULL, 'f'},
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{"string", required_argument, NULL, 's'},
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{0, 0, 0, 0}
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};
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const char* usage =
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"Usage strenc [options]\n\n"
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" -h --help\t\t\tShows this message\n"
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" -f --file\t\t\tInput file to be xored\n"
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" -s --string\t\t\tInput string to be xored\n"
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"\n";
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int c; // Used to grab individual args
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while(1) {
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int option_index = 0;
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c = getopt_long(argc, argv, "hf:s:", long_options, &option_index);
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if (c == -1) { // Break if no more args are present
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break;
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}
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switch(c) {
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case 'h':
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printf("%s", usage);
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exit(EXIT_SUCCESS);
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case 'f':
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if (pt != NULL) { // Exit if string is already set
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printf("Error string input already set\n");
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exit(EXIT_FAILURE);
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}
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pt = openFile(optarg, &pt_len);
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break;
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case 's':
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if (pt != NULL) { // Exit if file is already set
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printf("Error file input already set\n");
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exit(EXIT_FAILURE);
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}
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pt_len = strlen(optarg);
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pt = malloc(pt_len);
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memcpy(pt, optarg, pt_len);
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break;
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}
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}
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if (pt == NULL) { // Exit if plain text is NULL
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printf("Plain text has not been set\n");
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exit(EXIT_FAILURE);
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}
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key = genKey(pt, pt_len);
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ct = xorCharArray(pt, key, pt_len);
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printCStyleCharArray(ct, key, pt_len);
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// Freeing memory and returning
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free(pt);
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free(key);
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free(ct);
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exit(EXIT_SUCCESS);
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}
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