Actually, ZRTP supports SAS signing. This allows applications that use Axolotl to provide additional signatures to ZRTP, enabling sessions to be confirmed witho

Actually, ZRTP supports SAS signing. This allows applications that use Axolotl to provide additional signatures to ZRTP, enabling sessions to be confirmed without human intervention. See section 7.2 of RFC 6189 for details. Support for Axolotl integration was added to the very popular ZRTPCPP library on August 1, 2015. I think it's still a good idea for clients to display the SAS even when signed with another key. Especially when that session was established with a protocol which uses the TOFU model.