1 files changed, 94 insertions, 0 deletions
diff --git a/src/aes.c b/src/aes.c
new file mode 100644
index 0000000..5165992
--- /dev/null
+++ b/src/aes.c
@@ -0,0 +1,94 @@
+#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;
+}