1996-04-19 - Re: why compression doesn’t perfectly even out entropy

Header Data

From: Andrew Loewenstern <andrew_loewenstern@il.us.swissbank.com>
To: perry@piermont.com
Message Hash: 225291454e1d8d7eaf81a9dcacce852333f9de0338d95598c5e133e0b558213b
Message ID: <9604191736.AA00569@ch1d157nwk>
Reply To: <199604191221.IAA11773@jekyll.piermont.com>
UTC Datetime: 1996-04-19 21:59:25 UTC
Raw Date: Sat, 20 Apr 1996 05:59:25 +0800

Raw message

From: Andrew Loewenstern <andrew_loewenstern@il.us.swissbank.com>
Date: Sat, 20 Apr 1996 05:59:25 +0800
To: perry@piermont.com
Subject: Re: why compression doesn't perfectly even out entropy
In-Reply-To: <199604191221.IAA11773@jekyll.piermont.com>
Message-ID: <9604191736.AA00569@ch1d157nwk>
MIME-Version: 1.0
Content-Type: text/plain


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





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