Maybe no stego on eBay afterall

[Jon Simon]

At 1:55 PM -0400 7/19/02, Peter Wayner wrote:
>The basic scheme is very simple. Generally the inserted message has 
>higher entropy than the raw LSBs of an image. So the entropy of the 
>picture/message combo should be higher than the picture alone. So 
>you look at the entropy and choose all images that pass a threshold. 
>You can do better by using your understanding of normal images to 
>create more sophisticated statistics. But there's little you can do 
>about large images and small messages. As the proportion of changed 
>pixels drops, the statistics end up closer and closer to the norm.

If this is the case, then wouldn't a thorough stego program filter 
the image post hiding to lower the entropy, making searching by this 
method far less useful than its already sad state?
-Jon Simon

---------------------------------------------------------------------
The Cryptography Mailing List
Unsubscribe by sending "unsubscribe cryptography" to majordomo at wasabisystems.com