Want to Keep a Secret?
Well let me tell you how, but keep it quiet! The answer is Espionage by mindquirk.
So you always wanted to be a cipher? Then just type your message into Espionage and your done. It’s that easy! With the added iChat integration, it’s now easier than ever before to transmit secure messages. Scared somebody might just decode it? Then you can switch to one of the thirty codebooks. And, just to make sure that even the FBI can’t decode the message, you can create your own codebook through the builder.

Best of all you don’t have to leave behind a trail of credit card statements as evidence that you got Espionage because it’s totally free! You can download it now, and while your at it, decode this message:
Q”?pt]++bpQph]%”6pAOX!pO%bpH3;[2vW+PMwq9$3tp6]p2PX!p]n6\p


Not an app that i would normally use, but it’s fun to play with
This is quite cool, indeed.
That is a simple substitution cipher. It is very easily broken if one has enough text (a few sentances should do) and knows (or has a good guess at) which language it is in.
Might be fun to use with friends, but do not use this for any sensitive data.