why compression doesn't perfectly even out entropy

[Andrew Loewenstern]

Perry writes:
>  Furthermore, I suggest you look up the Venona intercept work
>  and tell me again about how far an advesary will go with a
>  tiny toehold.

The Venona breaks came because the NSA had a lot of encrypted traffic and  
some pads were used more than once, which is hardly a tiny toehold.  After  
years of dragging intercepted messages through each other, something finally  
popped out.  Messages encrypted with pads that were only used once are still  
unbroken, AFAIK, even though the pads were simply generated by clerks banging  
on keyboards.

Still, a tiny toehold is all a good analyist needs to break a non-OTP  
cryptosystem, which attempts to protect a lot of information with only a  
little bit entropy.


andrew