Still waiting for Google to implement OTR and ZRTP in Hangouts by default...especially now after all this.
1. Google is removing XMPP as protocol http://www.zdnet.com/google-moves-away-from-the-xmpp-open-me...
2. On the other hand, however, duckduck is giving us some alternatives https://duck.co/topic/duckduckgo-s-new-public-xmpp-jabber-se...
Public key cryptography is great for this, because it means if you match one person to a key, you've then reliably matched every message they sent and have fairly strong proof it's the same person.