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/*this program copyright Oren Watson. Do whatever you want with it.
This code has no warranty at all, ever.*/
#include "stdio.h"
#include "stdlib.h"
#include "string.h"
#define DEFAULT_KEYLEN 10
int memxor(char *a, char *b, int len){
int i;
for(i=0;i<len;i++)a[i]^=b[i];
}
int main(int argc, char **argv){
int keylen=DEFAULT_KEYLEN;
if(argc < 2){
fputs("You have to give a key file!\n",stderr);
return 1;
}
if(argc >= 3)sscanf(argv[2],"%d",&keylen);
else fputs("Taking default key length of 10\n",stderr);
char *key=malloc(keylen);
FILE *keyf=fopen(argv[1],"r");
fread(key,1,keylen,keyf);
fclose(keyf);
int i=keylen;
char *buf=malloc(keylen);
int j=0;
while(i==keylen){
i=fread(buf,1,keylen,stdin);
memxor(buf,key,i);
fwrite(buf,1,i,stdout);
if(j++==1 && i) fputs("Be advised that this encryption is only "
"completely secure if the key is at least as long as the text.\n",stderr);
}
return 0;
}
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