In:
2.5.1. UPNs and Certificates
Note: If a server is validating data received via iMIP, if the
"ORGANIZER" or "ATTENDEE" property said (e.g.) "ATTENDEE;CN=Joe Random
:juser@xxxxxxxxxxx" then the "juser@xxxxxxxxxxx" part should be
checked against the altSubjectName field of the certificate, and the
"Joe Random User" part should be checked against the CN component of
the altSubjectName DN. This is so the "ATTENDEE" property couldn't be
munged to something misleading like "ATTENDEE;CN=Joe Rictus
juser@xxxxxxxxxxx" and have it pass validation. This validation
will also defeat other attempts at confusion.
Had the ATTENDEE line had "User:" in the ATTENDEE lines:
"ATTENDEE;CN=Joe Random:User:juser@xxxxxxxxxxx"