A great post from [Matthew Green comparing different encryption apps for iOS][1]. Someone (I can’t find the source) on App.net sent this over to me and it is a great breakdown from someone who presumably knows his stuff.

Of the apps listed I use Wickr quite a bit. I thought it was pretty secure, but it looks like it is less secure than I thought. I just signed up for Silent Circle and will be testing that out. It’s a much more complicated system, but it looks to be far more secure of a system.

[1]: http://blog.cryptographyengineering.com/2013/03/here-come-encryption-apps.html?m=1