I’ve implemented tls-authz in GnuTLS but there has been a long discussion of the patent situation for that technology on the IETF list. A few days ago there was a new IPR Disclosure with a patent license for this technology:
https://datatracker.ietf.org/public/ipr_detail_show.cgi?&ipr_id=833
I evaluated this license from a free software perspective, here is my writeup: