TextSecure (the predecessor to Signal) used to support encrypted SMS.  You could send all the encrypted messages you want without using their centralized service.  Unfortunately, for whatever reason, they dropped that capability a few months ago.  Then, to add insult to injury, the app disables itself if you don&#x27;t update it for 6 months.<p>On the bright side, there&#x27;s now an open source fork called SMSSecure.  As the name implies, it does encrypted SMS.  It works pretty well.  I just hope the open source maintainers are keeping up with security updates to the protocol and not introducing any new bugs...