G.O.T.

GOT allows you to connect with your contacts through a dedicated and private GOT server, thus protecting all communications between network users with standard encryption algorithms.
Use geolocation to communicate your location.
Technical details:
• ZRTP key swap with 521-bit elliptic curve (secp521) Diffie-Hellman, AES-256 and SHA-384
• Calls are encrypted and authenticated by SRTP with AES-256 and 80-bit authentication tags
• All communication between GOT client and server is protected by TLS 1.2 with ECDHE, AES-256-GCM and SHA-384
• Makes extensive use of the phone’s data protection features