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/* ... */
#include <tinycrypt/cbc_mode.h>
#include <tinycrypt/constants.h>
#include <tinycrypt/utils.h>
int tc_cbc_mode_encrypt(uint8_t *out, unsigned int outlen, const uint8_t *in,
unsigned int inlen, const uint8_t *iv,
const TCAesKeySched_t sched)
{
uint8_t buffer[TC_AES_BLOCK_SIZE];
unsigned int n, m;
if (out == (uint8_t *) 0 ||
in == (const uint8_t *) 0 ||
sched == (TCAesKeySched_t) 0 ||
inlen == 0 ||
outlen == 0 ||
(inlen % TC_AES_BLOCK_SIZE) != 0 ||
(outlen % TC_AES_BLOCK_SIZE) != 0 ||
outlen != inlen + TC_AES_BLOCK_SIZE) {
return TC_CRYPTO_FAIL;
}{...}
(void)_copy(buffer, TC_AES_BLOCK_SIZE, iv, TC_AES_BLOCK_SIZE);
(void)_copy(out, TC_AES_BLOCK_SIZE, iv, TC_AES_BLOCK_SIZE);
out += TC_AES_BLOCK_SIZE;
for (n = m = 0; n < inlen; ++n) {
buffer[m++] ^= *in++;
if (m == TC_AES_BLOCK_SIZE) {
(void)tc_aes_encrypt(buffer, buffer, sched);
(void)_copy(out, TC_AES_BLOCK_SIZE,
buffer, TC_AES_BLOCK_SIZE);
out += TC_AES_BLOCK_SIZE;
m = 0;
}{...}
}{...}
return TC_CRYPTO_SUCCESS;
}{ ... }
int tc_cbc_mode_decrypt(uint8_t *out, unsigned int outlen, const uint8_t *in,
unsigned int inlen, const uint8_t *iv,
const TCAesKeySched_t sched)
{
uint8_t buffer[TC_AES_BLOCK_SIZE];
const uint8_t *p;
unsigned int n, m;
if (out == (uint8_t *) 0 ||
in == (const uint8_t *) 0 ||
sched == (TCAesKeySched_t) 0 ||
inlen == 0 ||
outlen == 0 ||
(inlen % TC_AES_BLOCK_SIZE) != 0 ||
(outlen % TC_AES_BLOCK_SIZE) != 0 ||
outlen != inlen) {
return TC_CRYPTO_FAIL;
}{...}
/* ... */
p = iv;
for (n = m = 0; n < outlen; ++n) {
if ((n % TC_AES_BLOCK_SIZE) == 0) {
(void)tc_aes_decrypt(buffer, in, sched);
in += TC_AES_BLOCK_SIZE;
m = 0;
}{...}
*out++ = buffer[m++] ^ *p++;
}{...}
return TC_CRYPTO_SUCCESS;
}{ ... }