Hi, for SIP signaling, we can use UDP, TCP or TLS transport. TLS is great for encrypting SIP message. However, I only need to use secret key (this is fixed in client and server) to encrypt message. How to create a custom transport that - encrypt message before sending - decrypt message upon receiving it -- Khoa Pham HCMC University of Science Faculty of Information Technology -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.pjsip.org/pipermail/pjsip_lists.pjsip.org/attachments/20130320/15905cdb/attachment-0001.html>