Re: Using compression before encryption in device-mapper

[Pascal Schmidt]

On Wed, 14 Apr 2004, Guillaume [iso-8859-15] Lacôte wrote:

> You are right that in this very case, the per-bit entropy will be
> (1 - 1/(1+1/8) ) ~ 12% lower than in the original text. The point is
> that this case (which has nothing to do with the case where a text can
> be well compressed or not, this is the worst _relative_ performance of
> dynamic versus static encoding) does not happen "too often".

I was only pointing out a corner case where your argument doesn't
hold. I completely agree that it is rather unlikely to happen with
real world data.

There is one exception, though: data that has already been compressed
before on a higher level; by the user, for example. However, in
that case you could say that what you're trying to accomplish has already
happened before during the original compression run.

-- 
Ciao,
Pascal
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