Apps with 'Encrypted VoIP calls' feature
Telegram is a messaging app with a focus on speed and security. It’s superfast, simple and free. It is like SMS, but more powerful.
TextSecure and RedPhone have been merged to create Signal!
Linphone is an internet phone or Voice Over IP phone (VoIP). With Linphone you can communicate freely with people over the internet, with voice, video, and text instant messaging.
Personal and business use online phone number with free US long distance calls and other free features.
Cloud-based phone centre solution with the 50+ advanced call features, ready to use in a minute. CloudTalk helps more than 1000 smart companies as DHL, Electronic Star, Yves Rocher deliver exceptional customer support & boost their sales.
twinme is a next generation secure instant messaging and High-Definition voice/video call service, protecting your privacy and giving you full control over each of your relationships and exchanged contents.
PBXware is the world’s first and most mature IP PBX Professional Open Standards Turnkey Telephony Platform. Bicom Systems’ softswitch is offered in the Business, Call Center and Multi-Tenant Editions.