71 lines
1.6 KiB
C
71 lines
1.6 KiB
C
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <assert.h>
|
|
#include "aes_core.h"
|
|
|
|
static void rk_init_ctr(struct ctr_state * state, const unsigned char *iv)
|
|
{
|
|
state->num = 0;
|
|
memset(state->ecount, 0, 16);
|
|
memcpy(state->ivec, iv, 16);
|
|
}
|
|
|
|
/* increment counter (128-bit int) by 1 */
|
|
static void rk_ctr128_inc(unsigned char *counter) {
|
|
unsigned int n=16;
|
|
unsigned char c;
|
|
|
|
do {
|
|
--n;
|
|
c = counter[n];
|
|
++c;
|
|
counter[n] = c;
|
|
if (c) return;
|
|
} while (n);
|
|
}
|
|
|
|
static void rk_crypto_ctr128_encrypt(const unsigned char *in, unsigned char *out,
|
|
int len, const void *key, unsigned char *ivec, unsigned char *ecount_buf,
|
|
unsigned int *num)
|
|
{
|
|
int n, l=0;
|
|
|
|
n = *num;
|
|
while (l<len) {
|
|
if (n==0) {
|
|
rk_aes_encrypt(ivec, ecount_buf, key);
|
|
rk_ctr128_inc(ivec);
|
|
}
|
|
out[l] = in[l] ^ ecount_buf[n];
|
|
++l;
|
|
n = (n+1) % 16;
|
|
}
|
|
|
|
*num = n;
|
|
}
|
|
|
|
/* XTS makes use of two different keys, usually generated by splitting
|
|
* the supplied block cipher's key in half.
|
|
* Because of the splitting, users wanting AES 256 and AES 128 encryption
|
|
* will need to choose key sizes of 512 bits and 256 bits respectively.
|
|
*/
|
|
int rk_aes_ctr_encrypt(const unsigned char *in, unsigned char *out,
|
|
unsigned long length, const unsigned char *key, const int key_len,
|
|
const unsigned char *ivec, const int enc)
|
|
{
|
|
RK_AES_KEY ks;
|
|
struct ctr_state state;
|
|
|
|
if(key_len != 16 && key_len != 24 && key_len != 32)
|
|
return -1;
|
|
|
|
rk_init_ctr(&state, ivec);
|
|
rk_aes_set_encrypt_key(key, key_len * 8, &ks);
|
|
rk_crypto_ctr128_encrypt(in, out, length, &ks, state.ivec, state.ecount, &state.num);
|
|
|
|
return 0;
|
|
}
|
|
|
|
|