XEP-0250 (C2C Authentication Using TLS) has been Deferred because of inactivity.
Abstract: This document describes how to negotiate TLS extensions when using TLS for end-to-end XML streams between two clients. It covers X.509 certificates with an without CA, the use of OpenPGP, Shared Remote Passwords (SRP) and how to use one extension to bootstrap a trust relationship. URL: http://www.xmpp.org/extensions/xep-0250.html If and when a new revision of this XEP is published, its status will be changed back to Experimental.