Lumicall

Convenient open source app makes free, encrypted calls using open standards.

The ultimate and most convenient way to make free, fully encrypted calls and text messages, this dialer uses the open standards SIP and ENUM to let you call any friend using Lumicall, as well as anyone using any of the other open-standards based VoIP clients, such as Jitsi, on smartphones and on desktop PCs. Includes support for ZRTP and SRTP encryption, DNS SRV, ENUM, TLS and ICE (Internet Connectivity Establishment), an advanced solution to traverse NAT firewalls.