Imagine that you want to send a secret message to your colleague at the CIA. You can encrypt it to prevent counterspies from reading it. But they'll still know you were sending some sort of message. There's a better option—steganography—which means "hidden writing." You tuck your secret away in an unexpected place, like an MP3 or a photo file, to conceal the fact you even shared any information at all.
But you can't hide much in those file types without it being suspiciously large. Executable files, aka applications, on the other hand, come in all sizes—making them an ideal place to embed lots of data. So two computer scientists created an algorithm that packages your encrypted data into an executable file of your choice. Then it spits out a new program that works just like the original—except that your secret cargo is inside. The research is in the International Journal of Internet Technology and Secured Transactions. [Rajesh Kumar Tiwari and G. Sahoo, "A Novel Steganographic Methodology for High-Capacity Data Hiding in Executable Files"]
Ideally, this handy trick would keep your data safe from prying eyes. Until somebody notices that you're sharing an inordinate number of executable files.
[The above text is an exact transcript of this podcast.]