mailing-list-archive-generator/_emails/1992/10/3c38d48ebe6788447fca198f92d44a9ffa68121b79032804da9a7944dc97d602.md

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1992-10-24 - entropy measures

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From: Eric Hughes <hughes@soda.berkeley.edu>
To: cypherpunks@toad.com
Message Hash: 3c38d48ebe6788447fca198f92d44a9ffa68121b79032804da9a7944dc97d602
Message ID: <9210240620.AA08036@soda.berkeley.edu>
Reply To: <9210231641.AA11868@xanadu.xanadu.com>
UTC Datetime: 1992-10-24 06:20:44 UTC
Raw Date: Fri, 23 Oct 92 23:20:44 PDT

Raw message

{% raw  %}From: Eric Hughes <hughes@soda.berkeley.edu>
Date: Fri, 23 Oct 92 23:20:44 PDT
To: cypherpunks@toad.com
Subject: entropy measures
In-Reply-To: <9210231641.AA11868@xanadu.xanadu.com>
Message-ID: <9210240620.AA08036@soda.berkeley.edu>
MIME-Version: 1.0
Content-Type: text/plain


Dean:
>Where does uuencoded [compressed] binary lie?  I would suspect it lies
>right around where encrypted text is.  

Right.

>Presumably straight encrypted
>text is statistically random [7..8], but that when you encrypt to
>just the ascii subset is when you lose the entropy.

Exactly.

uuencoding will have a slightly lower single-character entropy than
the ASCII armor PGP uses because just about every line begins with the
letter 'M'.  This will skew the distribution slightly.  But a better
way of distinguishing uuencoding and ascii armor is to see that in
falls in the same entropy class, and then just looking at the
alphabetic subsets used.

Eric




{% endraw %}

Thread

• Return to October 1992

• 1992-10-22 (Thu, 22 Oct 92 09:25:56 PDT) - BBS E-mail policy - omega@spica.bu.edu (The Omega)

  • 1992-10-23 (Thu, 22 Oct 92 23:02:09 PDT) - BBS E-mail policy - Eric Hughes <hughes@soda.berkeley.edu>
    • 1992-10-23 (Fri, 23 Oct 92 14:42:19 PDT) - BBS E-mail policy Now see if this number is in one of the following ranges: - tribble@xanadu.com (E. Dean Tribble)
      • 1992-10-24 (Fri, 23 Oct 92 23:20:44 PDT) - entropy measures - Eric Hughes <hughes@soda.berkeley.edu>
        • 1992-10-26 (Sun, 25 Oct 92 21:41:19 PPE) - Re: entropy measures - Eric Hollander <hh@soda.berkeley.edu>