Mr Shaddack... That's some interesting thinking there. The interesting thing is that no one might ever even notice the presence of this benevolent worm. It could go pretty much unchecked for a while. As for Variola's comment, you might be right. I just assumed there's some kind of relationship between LSB and those spatial freuencies wherein image information might be stored. Actually, I would still think there's a relationship, in which case an Echelon-like approach based on ffts and "noise templates" might be going on (hence the usefulness of jamming). Anyone got a TLA Operative Handbook? ANy mention in there of what kind of photos are best for Stego? How about cloud photos? (particularly where there are clouds of many different shapes and sizes present in the photo simultaneously.) -TD

From: Thomas Shaddack <shaddack@ns.arachne.cz> To: cypherpunks <cypherpunks@lne.com> Subject: Stego worm Date: Fri, 12 Dec 2003 01:10:24 +0100 (CET)

It's unknown to which extent the Adversary can detect presence of steganography in images being sent over the Net.

But whatever capabilities they have, they can be jammed.

Imagine a worm that spreads from machine to machine, and on the infected machine it finds all suitable JPEG files, generates some random data as source and encrypts them with random key, and stegoes them into the files.

In few days or even hours, a sizeable portion of images on the Net contains potentially detectable stegoed encrypted data.

Any Chinese want to get immortalized in Internet history?

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