diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 49fa597..db40dbf 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -251,6 +251,9 @@
 //#define MBEDTLS_SHA1_PROCESS_ALT
 //#define MBEDTLS_SHA256_PROCESS_ALT
 //#define MBEDTLS_SHA512_PROCESS_ALT
+//#define MBEDTLS_DES_SETKEY_ALT
+//#define MBEDTLS_DES_CRYPT_ECB_ALT
+//#define MBEDTLS_DES3_CRYPT_ECB_ALT
 
 /**
  * \def MBEDTLS_AES_ROM_TABLES