Simlar

Simlar offers free, encrypted internet calls. Just pick a contact and call—it's that simple. Contacts using Simlar appear automatically, and you can easily invite friends (works on iPhones too). It uses ZRTP encryption to keep calls tap-proof. Verify a short code on the first call for extra security. Open-source, free, and needs a stable connection (1MB per 2 mins). Learn more at simlar.org.