diff --git a/Romulus-M/encrypt_wrapper.c b/Romulus-M/encrypt_wrapper.c
index 0737e4a..ffff5f3 100644
--- a/Romulus-M/encrypt_wrapper.c
+++ b/Romulus-M/encrypt_wrapper.c
@@ -125,6 +125,11 @@ int decrypt(packetEx *packet, unsigned char *inBuf, UINT16 len, unsigned char *k
     // n = nonce, CRYPTO_NPUBBYTES size 16
     unsigned char *npub = &inBuf[loc];
     loc += CRYPTO_NPUBBYTES;
+    
+    if ((len - loc) < 0 )
+    {
+        return 1;
+    }
 
     // ciphertext - in, MAX 16 bytes larger than plaintext - defined as CRYPTO_ABYTES
     int clen = len - loc;