46 lines
960 B
C++
46 lines
960 B
C++
#include "rc4.h"
|
|
#include <iterator>
|
|
|
|
spiceapi::RC4::RC4(uint8_t *key, size_t key_size) {
|
|
|
|
// initialize S-BOX
|
|
for (size_t i = 0; i < std::size(s_box); i++)
|
|
s_box[i] = (uint8_t) i;
|
|
|
|
// check key size
|
|
if (!key_size)
|
|
return;
|
|
|
|
// KSA
|
|
size_t j = 0;
|
|
for (size_t i = 0; i < std::size(s_box); i++) {
|
|
|
|
// update
|
|
j = (j + s_box[i] + key[i % key_size]) % std::size(s_box);
|
|
|
|
// swap
|
|
auto tmp = s_box[i];
|
|
s_box[i] = s_box[j];
|
|
s_box[j] = tmp;
|
|
}
|
|
}
|
|
|
|
void spiceapi::RC4::crypt(uint8_t *data, size_t size) {
|
|
|
|
// iterate all bytes
|
|
for (size_t pos = 0; pos < size; pos++) {
|
|
|
|
// update
|
|
a = (a + 1) % std::size(s_box);
|
|
b = (b + s_box[a]) % std::size(s_box);
|
|
|
|
// swap
|
|
auto tmp = s_box[a];
|
|
s_box[a] = s_box[b];
|
|
s_box[b] = tmp;
|
|
|
|
// crypt
|
|
data[pos] ^= s_box[(s_box[a] + s_box[b]) % std::size(s_box)];
|
|
}
|
|
}
|