diff --git a/lib/asn1/pkinit.asn1 b/lib/asn1/pkinit.asn1
index 6912116b6..e89a7217a 100644
--- a/lib/asn1/pkinit.asn1
+++ b/lib/asn1/pkinit.asn1
@@ -29,6 +29,8 @@ id-pkinit-ms-san OBJECT IDENTIFIER ::=
   { iso(1) org(3) dod(6) internet(1) private(4) 
     enterprise(1) microsoft(311) 20 2 3 }
 
+MS-UPN-SAN ::= UTF8String
+
 pa-pk-as-req INTEGER ::=                  16
 pa-pk-as-rep INTEGER ::=                  17