diff --git a/src/ciphers/aes/aes.c b/src/ciphers/aes/aes.c
index 8ba1bfcc..0352d209 100644
--- a/src/ciphers/aes/aes.c
+++ b/src/ciphers/aes/aes.c
@@ -295,6 +295,10 @@ int ECB_ENC(const unsigned char *pt, unsigned char *ct, const symmetric_key *ske
     LTC_ARGCHK(skey != NULL);
 
     Nr = skey->rijndael.Nr;
+
+    if (Nr < 2 || Nr > 16)
+        return CRYPT_INVALID_ROUNDS;
+
     rk = skey->rijndael.eK;
 
     /*
@@ -475,6 +479,10 @@ int ECB_DEC(const unsigned char *ct, unsigned char *pt, const symmetric_key *ske
     LTC_ARGCHK(skey != NULL);
 
     Nr = skey->rijndael.Nr;
+
+    if (Nr < 2 || Nr > 16)
+        return CRYPT_INVALID_ROUNDS;
+
     rk = skey->rijndael.dK;
 
     /*