documentation update

README.md

@@ -189,6 +189,8 @@ if ok, creds, err := serivce.ValidateAPREQ(mt.APReq, kt, r.RemoteAddr); ok {
 [text](https://www.ietf.org/rfc/rfc6806.txt) [html](https://tools.ietf.org/html/rfc6806.html)
 * RFC 6113 A Generalized Framework for Kerberos Pre-Authentication
 [text](https://www.ietf.org/rfc/rfc6113.txt) [html](https://tools.ietf.org/html/rfc6113.html)
+* RFC 8009 AES Encryption with HMAC-SHA2 for Kerberos 5
+[text](https://www.ietf.org/rfc/rfc8009.txt) [html](https://tools.ietf.org/html/rfc8009)
 * [IANA Assigned Kerberos Numbers](http://www.iana.org/assignments/kerberos-parameters/kerberos-parameters.xhtml)
 * [HTTP-Based Cross-Platform Authentication by Using the Negotiate Protocol - Part 1](https://msdn.microsoft.com/en-us/library/ms995329.aspx)
 * [HTTP-Based Cross-Platform Authentication by Using the Negotiate Protocol - Part 2](https://msdn.microsoft.com/en-us/library/ms995330.aspx)

iana/keyusage/constants.go

@@ -1,4 +1,4 @@
-// Key usage assigned numbers.
+// Kerberos 5 key usage assigned numbers.
 package keyusage
 
 const (