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#include <mcrypt.h>
#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <time.h>
#include "aes.h"
#include "util.h"
#include "aeswepd.h"
#define MAX_CACHE 10
static MCRYPT m = MCRYPT_FAILED;
struct cache_entry {
uint8_t key[AES_KEY_LEN];
uint8_t data[AES_KEY_LEN];
uint8_t result[AES_KEY_LEN];
time_t timestamp;
};
static struct cache_entry cache[MAX_CACHE];
static int n_cache = 0;
int aes_crypt(uint8_t *key, uint8_t *data, uint8_t *result) {
int r, j;
struct cache_entry *e;
time_t now;
for (j = 0; j < n_cache; j++)
if (!memcmp(cache[j].key, key, AES_KEY_LEN) && !memcmp(cache[j].data, data, AES_KEY_LEN)) {
//fprintf(stderr, "Cache hit\n");
memcpy(result, cache[j].result, AES_KEY_LEN);
return 0;
}
//fprintf(stderr, "Cache miss\n");
if (m == MCRYPT_FAILED) {
if ((m = mcrypt_module_open("rijndael-128", NULL, "ecb", NULL)) == MCRYPT_FAILED) {
fprintf(stderr, "Failed to open rijndael mcrypt module\n");
return -1;
}
}
if ((r = mcrypt_generic_init(m, key, AES_KEY_LEN, NULL)) != 0) {
fprintf(stderr, "Failed to encrypt: %s\n", mcrypt_strerror(r));
return -1;
}
memcpy(result, data, AES_KEY_LEN);
if (mcrypt_generic(m, result, AES_KEY_LEN) != 0) {
fprintf(stderr, "mdecrypt_generic() failed.\n");
return -1;
}
if (mcrypt_generic_deinit(m) != 0) {
fprintf(stderr, "mdecrypt_generic() failed.\n");
return -1;
}
now = time(NULL);
if (n_cache < n_max_keys)
e = &cache[n_cache++];
else {
if (n_cache > n_max_keys)
n_cache = n_max_keys;
e = NULL;
for (j = 0; j < n_cache; j++)
if (!e || cache[j].timestamp < e->timestamp)
e = &cache[j];
}
memcpy(e->key, key, AES_KEY_LEN);
memcpy(e->data, data, AES_KEY_LEN);
memcpy(e->result, result, AES_KEY_LEN);
e->timestamp = now;
return 0;
}
int aes_done(void) {
if (m != MCRYPT_FAILED) {
mcrypt_module_close(m);
m = MCRYPT_FAILED;
}
n_cache = 0;
return 0;
}
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