[Cryptography] Compression before encryption?

Tom Mitchell mitch at niftyegg.com
Fri Jan 9 21:21:35 EST 2015

On Fri, Jan 9, 2015 at 4:22 AM, Stephan Neuhaus <stephan.neuhaus at zhaw.ch>

> Dear list,
> I have come across the recommendation to "compress before you encrypt", on
> the grounds that this makes plaintext recognition through frequency
> analysis much harder.

This is a tempting practice.   Compression after encrypt will see more
apparently random
data and defeat the compression code.   Perhaps making the file bigger.

Known header signatures simplify attacks and weaken the result.

  T o m    M i t c h e l l
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