Encrypted voice and IM for Android

End-to-End Encrypted Cell Phone Calls.

Android app. (Slashdot thread.)

[Schneier on Security]

From the article:

RedPhone uses ZRTP, an open source Internet voice cryptography scheme created by Phil Zimmermann, inventor of the widely-used Pretty Good Privacy or PGP encryption.

[…]

TextSecure uses a similar scheme developed by cryptographers Ian Goldberg and Nikita Borisov known as “Off The Record” to exchange scrambled text messages.

This means that you could talk securely to anyone using Zfone on a computer, and IM securely to anyone with Adium or another app that supports the OTR protocol.

There’s also this rather important distinction from Skype, the “security” of which I’ve criticized before:

Whisper Systems’ apps aren’t the first to bring encrypted VoIP to smartphones. But apps like Skype and Vonage don’t publish their source code, leaving the rigor of their security largely a matter of speculation.