diff --git a/aes.h b/aes.h
index 624b4ab..0edbf77 100644
--- a/aes.h
+++ b/aes.h
@@ -18,22 +18,22 @@
   #define ECB 1
 #endif
 
-#define AES128
+#define AES128 1
 
-#if defined(ECB) && ECB
+#if defined(ECB) && (ECB == 1)
 
 void AES_ECB_encrypt(const uint8_t* input, const uint8_t* key, uint8_t *output, const uint32_t length);
 void AES_ECB_decrypt(const uint8_t* input, const uint8_t* key, uint8_t *output, const uint32_t length);
 
-#endif // #if defined(ECB) && ECB
+#endif // #if defined(ECB) && (ECB == !)
 
 
-#if defined(CBC) && CBC
+#if defined(CBC) && (CBC == 1)
 
 void AES_CBC_encrypt_buffer(uint8_t* output, uint8_t* input, uint32_t length, const uint8_t* key, const uint8_t* iv);
 void AES_CBC_decrypt_buffer(uint8_t* output, uint8_t* input, uint32_t length, const uint8_t* key, const uint8_t* iv);
 
-#endif // #if defined(CBC) && CBC
+#endif // #if defined(CBC) && (CBC == 1)
 
 
 #endif //_AES_H_