diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 1a057a4..a2f1875 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -3863,6 +3863,25 @@
 
 /* \} SECTION: Compile-time SSL configuration */
 
+/**
+ * \def MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH
+ *
+ * Use only 128-bit keys in AES operations.
+ *
+ * Uncommenting this macro removes support for AES operations that are using 192
+ * or 256-bit keys.
+ *
+ * Tradeoff: Uncommenting this macro reduces ROM footprint by ~200 bytes.
+ *
+ * If uncommented, uncomment also MBEDTLS_CTR_DRBG_USE_128_BIT_KEY
+ *
+ * Module:  library/aes.c
+ *
+ * Requires: MBEDTLS_AES_C
+ *
+ */
+//#define MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH
+
 /* Target and application specific configurations
  *
  * Allow user to override any previous default.