diff --git a/include/polarssl/oid.h b/include/polarssl/oid.h
index 669ad53..5f20b56 100644
--- a/include/polarssl/oid.h
+++ b/include/polarssl/oid.h
@@ -195,6 +195,7 @@
 
 /* RFC 4055 */
 #define OID_RSASSA_PSS          OID_PKCS1 "\x0a" /**< id-RSASSA-PSS ::= { pkcs-1 10 } */
+#define OID_MGF1                OID_PKCS1 "\x08" /**< id-mgf1 ::= { pkcs-1 8 } */
 
 /*
  * Digest algorithms