Twilio Asterisk Secure Trunking HOWTO
This is a short guide on how to set up an encrypted VoIP system using Twilio and Asterisk. I was a little annoyed that just about everything these days still uses unencrypted RTP for media (though just about everyone supports SIP over TLS). So I spent a weekend looking at options, and settled on a totally overkill solution involving Twilio's secure trunking to an Asterisk PBX. While all bets are off once it hits the PSTN, at least you won't be blasting your conversations over the internet in clear text.