I've used the Red Phone app (Whisper Systems) on Android, and to me, it seems to provide only a half measure of encryption, in that one can easily identify the source.
"RedPhone uses your normal mobile number for addressing, so there's no need to have yet another identifier or account name;" [http://www.whispersys.com]
Seems to me, like the above poster stated, this can easily single you out for a head-kicking.
Of course, the government could always pass a law outlawing civilians from possessing any type of encryption technology. The Egyptian government is on the verge of collapse, and as anyone who has ever watched a war movie knows, the first thing you want to do is to hinder the enemy's communication abilities; which is exactly what they did by shutting everything down. But, one has to fight in a nice way now (unless you are the US) in order to not piss off the western allies, so their next move would probably be something more subtle.
