diff --git a/boot/zephyr/include/config-rsa.h b/boot/zephyr/include/config-rsa.h
index c6fa05a..d27acf9 100644
--- a/boot/zephyr/include/config-rsa.h
+++ b/boot/zephyr/include/config-rsa.h
@@ -58,6 +58,7 @@
 #define MBEDTLS_MD_C
 #define MBEDTLS_OID_C
 #define MBEDTLS_SHA256_C
+#define MBEDTLS_AES_C
 
 /* Save RAM by adjusting to our exact needs */
 #define MBEDTLS_ECP_MAX_BITS             2048