diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 2927b2c503411944af6990f9f8139560ba0cb8b4..31df7605bafbf0d42011d5a638a215785a021a30 100755
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -1260,7 +1260,7 @@
  *
  * This enables support for RSAES-OAEP and RSASSA-PSS operations.
  */
-// #define MBEDTLS_PKCS1_V21
+#define MBEDTLS_PKCS1_V21
 
 /**
  * \def MBEDTLS_RSA_NO_CRT