Twitter has made an interesting acquisition… Whisper Systems.

Whisper Systems specializes in developing security and privacy solutions for mobile platforms.

The company has worked on various platforms including Android which is now the most popular smartphone OS in the world.

Whisper Systems spoke about the acquisition deal:

The Whisper Systems software as our users know it will live on (and we have some surprises in store that we’re excited about), but there is unfortunately a transition period where we will have to temporarily take our products and services offline. RedPhone service will be interrupted immediately, but FlashBack users have a month to pull off any backup data they would like before that service also goes offline.