1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
|
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
int main(int argc, char *argv[]) {
//reads a message <4096B and XORs it with key argv[1] in file argv[2]
//message ends with string "@@@" after a white character.
//To retrieve the original message, use onetimebluh.c
FILE * keyfile = fopen(argv[1],"r");
FILE * crypt = fopen(argv[2],"w");
char msg[4096];
printf("Write a message.\n It will be encrypted in file %s ",argv[2]);
printf("with key %s\n",argv[1]);
printf("When you're done, use the EOF sequence @@@. It must follow a white space!\n");
char c_aux;
int i=0,k=0;
//scanf terminates at every white character, must be called by a While
// "i" tells where you are in msg (which is overwritten each time)
// "k" tells where you are in crypt
while(strcmp(msg,"@@@"))
{
scanf("%s",msg);
i=0;
while(msg[i]!='\0') {
fscanf(keyfile,"%c", &c_aux);
fprintf(crypt,"%c",msg[i]^c_aux);
i++;
k++;
}
fscanf(keyfile,"%c",&c_aux);
fprintf(crypt,"%c",' '^c_aux);
k++;
}
while (k<4096){
// fills the message with @s
fscanf(keyfile,"%c",&c_aux);
fprintf(crypt,"%c",'@'^c_aux);
k++;}
fclose(crypt);
}
|
