http://www.rfc-editor.org/rfc/rfc8129.txt
RFC 8129: Authentication Indicator in Kerberos Tickets, A. Jain, N. Kinder, N. McCallum2017-03-01T23:00:00-00:00This document updates RFC 4120, as it specifies an extension in the Kerberos protocol. It defines a new authorization data type, AD-AUTHENTICATION-INDICATOR. The purpose of introducing this data type is to include an indicator of the strength of a client's authentication in service tickets so that application services can use it as an input into policy decisions.