Baresip app implements a very basic secure and fully open source VoIP User Agent based on baresip https://github.com/alfredh/baresip SIP library .

Currently baresip app supports voice calls and text messages voicemail Message Waiting Indication (MWI) and incoming call transfers via REFER method. Voice is coded with PCMU/PCMA G.722.1 iLBC or Opus codecs. Security is achieved via TLS signaling transport and ZRTP or (DTLS) SRTP media encapsulation.

Development of baresip app is motivated by need for a secure open source SIP based VoIP User Agent for Android that does not depend on proprietary third party push notification services.

Source code is available at GitHub https://github.com/juha-h/baresip-studio where also issues can be reported.