imabonehead

"Steganography uses innocuous documents, usually an image file, as carriers for secret messages. Unlike encryption, steganography encodes the message while at the same time concealing the fact that a message is being sent at all. The Greek-derived name means “covered writing.” The earliest steganographers were said to be Greek generals who tattooed sensitive information onto the shaved heads of messengers. Once the hair grew back, the messenger could travel without suspicion to the intended recipient, who “decrypted” the secret message by shaving the messenger’s head again. In its current incarnation, steganography often makes use of e-mail, an ideal carrier for any corporate spy, disgruntled employee, or terrorist." - imabonehead via Bookmarklet

"Bertolino’s method turns this technology on itself. The key to jamming steganography, he says, is using steganography—what he calls “double-stegging.” Double-stegging adds some noise, scrambling some of the image’s least-significant bits. “As long as you’re damaging at least some part of the file,” Bertolino explains, the hidden file becomes garbled and cannot be deciphered." - imabonehead