1997-12-01 - Re: Quoting Portions of a Signed Document

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From: nobody@REPLAY.COM (Anonymous)
To: cypherpunks@Algebra.COM
Message Hash: 64eba2a93db934dbd33e387d0c999d3c674267a28ae62f5ebff264dfacb22154
Message ID: <199712010131.CAA03134@basement.replay.com>
Reply To: N/A
UTC Datetime: 1997-12-01 01:38:21 UTC
Raw Date: Mon, 1 Dec 1997 09:38:21 +0800

Raw message

From: nobody@REPLAY.COM (Anonymous)
Date: Mon, 1 Dec 1997 09:38:21 +0800
To: cypherpunks@Algebra.COM
Subject: Re: Quoting Portions of a Signed Document
Message-ID: <199712010131.CAA03134@basement.replay.com>
MIME-Version: 1.0
Content-Type: text/plain

Thanks to everybody for their interesting contributions to the partial
signature problem.

Anonymous <anon@anon.efga.org> writes:
>A more general approach calculates the document hash in a line
>oriented way.  Normally we start at the top and work down through the
>document to get the hash, which is signed.  Instead, we would
>calculate a hash for each line of the document separately, and then
>combine them using a tree.

This approach looks like the best to me.  It's a bit cumbersome for
the person doing the quoting, but that's as it should be.

Brian B. Riley writes:
>  I haven't been follwing this thread that closely, but skimming mch
>of it and then rereading this whole post, I must concur that the
>context issue renders much of the discussion moot unless you can not
>only relate individual sub-blocks to the whole message it came from
>in the proper order ... it seems to me we are right back where we
>started, quoting referenced message(s) in entirety.
>  It occurrs to me that if an issue is important enough that the
>veracity and autheticity of a given passage is that critical,
>including entire messages is of trivial concern. Now it could be
>handled by the discussion participant quoting out of context and
>'footnoting' his quote with a message ID. The message corresponding
>to that ID has its entire text is signed and publicly stored and
>accessible. If it needs to be checked then go check it, if not take
>it on faith and read on.

It's easy to see why we would want other people to sign with
signatures which enable partial quoting, but it's less clear why we
would sign our own messages this way.

For instance, somebody might want to quote my private e-mail out of
context where I say "Yes, I'm real glad I got rid of that guy.  He was
really a pest."  But they might not want to quote the part of the
message where I say "Thanks for the latest shipment of plastic
explosives."  In order to authenticate their claim they have to reveal
the entire message.  If they must quote the entire message for
authentication, it will discourage tacky behavior such as relaying
private messages.

So, this is sort of a solution looking for an application.  It seems
like an interesting problem and I have a strong intuitive sense that a
use for it will present itself at some point.

Monty Cantsin
Editor in Chief
Smile Magazine

Subject: Re: Quoting Portions of a Signed Document
To: cypherpunks@algebra.com
16A5942B6EED349ECF4594C784DFD177 [Cantsin Protocol No. 1]
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