diff --git a/mtproto-common.c b/mtproto-common.c
index 7ca8bee..ceeb5c5 100644
--- a/mtproto-common.c
+++ b/mtproto-common.c
@@ -348,6 +348,7 @@ void init_aes_unauth (const char server_nonce[16], const char hidden_client_nonc
   } else {
     AES_set_decrypt_key (aes_key_raw, 32*8, &aes_key);
   }
+  memset (aes_key_raw, 0, sizeof (aes_key_raw));
 }
 
 void init_aes_auth (char auth_key[192], char msg_key[16], int encrypt) {
@@ -387,6 +388,7 @@ void init_aes_auth (char auth_key[192], char msg_key[16], int encrypt) {
   } else {
     AES_set_decrypt_key (aes_key_raw, 32*8, &aes_key);
   }
+  memset (aes_key_raw, 0, sizeof (aes_key_raw));
 }
 
 int pad_aes_encrypt (char *from, int from_len, char *to, int size) {
diff --git a/queries.c b/queries.c
index 53bfdcd..fddc565 100644
--- a/queries.c
+++ b/queries.c
@@ -746,6 +746,7 @@ char *encrypt_decrypted_message (struct secret_chat *E) {
   AES_KEY aes_key;
   AES_set_encrypt_key (key, 256, &aes_key);
   AES_ige_encrypt ((void *)encr_ptr, (void *)encr_ptr, 4 * (encr_end - encr_ptr), &aes_key, iv, 1);
+  memset (&aes_key, 0, sizeof (aes_key));
 
   return (void *)msg_key;
 }
@@ -1290,15 +1291,14 @@ void send_part (struct send_file *f) {
     if (f->encr) {
       if (x & 15) {
         assert (f->offset == f->size);
-        if (x & 15) {
-          secure_random (buf + x, (-x) & 15);
-          x = (x + 15) & ~15;
-        }
+        secure_random (buf + x, (-x) & 15);
+        x = (x + 15) & ~15;
       }
       
       AES_KEY aes_key;
       AES_set_encrypt_key (f->key, 256, &aes_key);
       AES_ige_encrypt ((void *)buf, (void *)buf, x, &aes_key, f->iv, 1);
+      memset (&aes_key, 0, sizeof (aes_key));
     }
     out_cstring (buf, x);
     if (verbosity >= 2) {
@@ -1803,6 +1803,7 @@ int download_on_answer (struct query *q) {
     AES_KEY aes_key;
     AES_set_decrypt_key (D->key, 256, &aes_key);
     AES_ige_encrypt (ptr, ptr, len, &aes_key, D->iv, 0);
+    memset (&aes_key, 0, sizeof (aes_key));
     if (len > D->size - D->offset) {
       len = D->size - D->offset;
     }
diff --git a/structures.c b/structures.c
index 47eb941..ddb8f1f 100644
--- a/structures.c
+++ b/structures.c
@@ -1376,6 +1376,7 @@ int decrypt_encrypted_message (struct secret_chat *E) {
   AES_KEY aes_key;
   AES_set_decrypt_key (key, 256, &aes_key);
   AES_ige_encrypt ((void *)decr_ptr, (void *)decr_ptr, 4 * (decr_end - decr_ptr), &aes_key, iv, 0);
+  memset (&aes_key, 0, sizeof (aes_key));
 
   int x = *(decr_ptr);
   if (x < 0 || (x & 3)) {