diff --git a/main/main.c b/main/main.c
index 91bbe6e..cd9edec 100644
--- a/main/main.c
+++ b/main/main.c
@@ -190,8 +190,8 @@ GroupTextMessage decodeGroupMessage(FrameStruct frame) {
 
   size_t plaintextLen = 0;
 
-  mac_then_decrypt(aes_key, frame.payload + index, frame.payloadLen - index, tmp, &plaintextLen);
-  if (plaintextLen == 0) {
+  unsigned char res = mac_then_decrypt(aes_key, frame.payload + index, frame.payloadLen - index, tmp, &plaintextLen);
+  if (plaintextLen == 0 || res != 0) {
     printf("error decrypting");
   }