From: PhneCards@aol.com
Date: Thu, 26 Sep 1996 13:09:17 +0800
To: cypherpunks@toad.com
Subject: Re: An idle thought on CBC and block lengths
Message-ID: <960925181213_529562658@emout15.mail.aol.com>
MIME-Version: 1.0
Content-Type: text/plain


Did you know this company is using your email address as part of
an unlawful email bomb?

I would advise you to write to them at cypherpunks@toad.com
and owner-cypherpunks@toad.com and advise them to stop
using your email address for this type of activity.

It is illegal to use a invalid return email address.  If this continues, I
will
be forced to prosecute the return email address - which they are
making to look like you.

Below is the letter that I received in my email box
=================================================

In a message dated 96-09-25 15:52:17 EDT, you write:

>Subj:	An idle thought on CBC and block lengths
>Date:	96-09-25 15:52:17 EDT
>From:	osborne@gateway.grumman.com (Rick Osborne)
>Sender:	owner-cypherpunks@toad.com
>To:	cypherpunks@toad.com
>
>So I was sitting bored at home and thinking to myself: CBC is cool.
>Without the key, you're screwed because a single bit error propagates
>throughout the entire message.  But then I was thinking, yeah, but you can
>still eventually get the ONE key.  So I began to wonder what the difference
>in security is between encrypting an entire M with just one K in CBC, or
>encrypting M with permutations of K over specific block lengths.
>
>On the one hand you've got just one key, which makes it that much harder to
>find in the keyspace.  On the other hand, If evil interloper Eve gets her
>hands it, she has to find all of the keys to get all of M.  (Assuming she
>is using brute force and can't necessarily find the master K to permute
>into the subkeys.)
>
>The downsides are of course that on the one side you've got just one key,
>and once you get it, you get M.  But on the other hand, you can get any one
>part of the message with less difficulty because of the higher number of
>keys.  And, of course, if your master K is easy to brute force, then it's
>actually worse than the first option.
>
>Does anyone have opinions / knowledge of which is better?
>
>
>____________________________________________________________
>Rick Osborne                     osborne@gateway.grumman.com
>"The universe doesn't give you any points for doing things that are easy."
>
>
>
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>Date: Wed, 25 Sep 1996 08:56:45 -0400
>To: cypherpunks@toad.com
>From: Rick Osborne <osborne@gateway.grumman.com>
>Subject: An idle thought on CBC and block lengths
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