<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">Does anyone know about the end to end messaging protocol used by Viber in the release they announced yesterday? I believe it’s closed source, but I’d be curious to know if they have posted the general protocol anywhere. I’ve not found anything yet. I’m curious to know if it’s based on the ratchet used for Signal or not.</div><div class=""><br class=""></div><a href="https://support.viber.com/customer/portal/articles/2017401-viber-security-faq" class="">https://support.viber.com/customer/portal/articles/2017401-viber-security-faq</a><div class=""><br class=""></div><div class="">What I really like is the improved UX for authentication I’ve not seen yet. They use their own real-time channel (voice) to guide the user through the fingerprint readout. Now, real-time channels are available through many tools, but I think this is the first time I’ve seen a text messaging service do this (ZRTP in video calls and voice calls notwithstanding).</div><div class=""><br class=""></div><div class="">What I’d like to see next: A way to prevent accepting the fingerprint without reading it similar to SafeSlinger, with perhaps a shorter hash to confirm.</div><div class=""><br class=""></div><div class=""><div class="">Cheers,</div><div class="">Mike</div><div class=""><br class=""></div><div class="">Michael W. Farb</div><div class="">Research Programmer, Carnegie Mellon University CyLab</div><div class=""><a href="http://www.cylab.cmu.edu/safeslinger" class="">www.cylab.cmu.edu/safeslinger</a></div></div></body></html>