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It shouldn't matter so long as redundancy between headers and body result in a smaller cyphertext.


Due to the nature of compression algorithms using BWT, changing a single byte in the uncompressed data might give you +/- 5 bytes difference in the size of the compressed data; that makes pulling off an attack like this much, much, much more difficult. Don't get me wrong, you'll get variance with deflate as well, but it's nowhere near the level of something like bzip2.

I do a lot of experimentation with new compression techniques for web demos, and I recently implemented my own compression algo from scratch based around the same building blocks as bzip2. The variance I saw was just staggering; a tiny change in my source material would totally warp the output.


I would love to see somebody proving or disproving whether BZip2 is susceptible to these type of attacks. My assumption is that small changes in MTF transformation and tweaks in creating encoding table will make it impossible to crack using this method.




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