diff --git a/lib/des/rsa.h b/lib/des/rsa.h
index 829781314..56558128b 100644
--- a/lib/des/rsa.h
+++ b/lib/des/rsa.h
@@ -122,6 +122,7 @@ struct RSA {
 #define RSA_FLAG_SIGN_VER		0x40
 
 #define RSA_PKCS1_PADDING		1
+#define RSA_PKCS1_OAEP_PADDING		4
 #define RSA_PKCS1_PADDING_SIZE		11
 
 /*