Specifies the allowable elapsed time in seconds since the last time the End-User was actively authenticated by the OP. If the elapsed time is greater than this value, the OP MUST attempt to actively re-authenticate the End-User.
The max_age request parameter corresponds to the OpenID 2.0 PAPE OpenID.PAPE max_auth_age request parameter.)
When Max_age is used, the Identity Token returned MUST include an auth_time Claim Value.