int main(void){
uchar s[256];
uchar key[256];
uchar word[256];
size_t key_len;
struct dynamic_str encode, decode;
strcpy((char *)key, "do_or_die"); // > 255 == stack overflow
strcpy((char *)word, "\natirei o pau na dilma, mas a dilma não morreu\n");
key_len = strlen((const char *)key);
ksa(s, key, key_len);
prga(word, s, &encode);
printf("RC4:\n'%s'\n", encode.ptr);
ksa(s, key, key_len);
prga(encode.ptr, s, &decode);
printf("Decoded:\n'%s'\n", decode.ptr);
free(decode.ptr);
free(encode.ptr);
return 0;
}
/* Encrypt or Decrypt */
void rc4(u_char *key, u_char *input, u_char *output, int keylen, int msglen) {
int i;
u_char State[256];
u_char *keystream;
initialize(State);
ksa(State, key, keylen);
printf("\n--- Tamaño del mensaje %d\n", msglen);
keystream = prng(State, msglen);
for(i=0; i<msglen; i++)
output[i] = input[i] ^ keystream[i];
printf("\n--- Key Generation ---\nKey: %s\n\n", key);
printf("Keystream:\n");
for(i=0; i<msglen; i++) {
if(i%16==0) {
printf("\n");
printf("%d:\t", i);
}
if(keystream[i]<16)
printf("0%x ", keystream[i]);
else
printf("%x ", keystream[i]);
}
}
static bool decrypt_file(const char *fname, bool from_update)
{
uint32_t header[5];
size_t datlen;
ksa(secret_key, 16);
FILE *inp;
struct stat fst;
if((inp = fopen(fname, "rb")) == NULL){
printf("Can't open input file '%s'", fname);
return false;
}
if(fstat(fileno(inp), &fst) != 0){
fclose(inp);
printf("Cannot stat file '%s'\n", fname);
return false;
}
if(from_update){
if(fread(&header, sizeof(uint32_t), 5, inp) != 5){
fclose(inp);
printf("Can't read the header - file '%s' is less than 20 bytes long?\n", fname);
return false;
}
datlen = header[4];
}else{
datlen = fst.st_size;
}
if((decoded = (char *)malloc(datlen+1)) == NULL){
printf("malloc failed!\n");
return false;
}
memset(decoded, 0, datlen+1);
size_t i;
size_t len = fread(decoded, 1, datlen, inp);
(void) len;
for(i = 0; i < datlen; ++i) decoded[i] ^= rc4();
fclose(inp);
//inp = fopen("tmp.dump", "w");
//fwrite(decoded, 1, datlen, inp);
//fclose(inp);
return true;
}
