From: Ray Arachelian <sunder@brainlink.com>
Date: Thu, 27 Nov 1997 02:49:45 +0800
To: cypherpunks <cypherpunks@toad.com
Subject: Re: Quoting Portions of a Signed Document
In-Reply-To: <199711252109.WAA05443@basement.replay.com>
Message-ID: <Pine.SUN.3.96.971126131804.24545B-100000@beast.brainlink.com>
MIME-Version: 1.0
Content-Type: text/plain



On Tue, 25 Nov 1997, Anonymous wrote:

> A crude approach would be to sign every paragraph or line separately,
> but that's obviously inelegant.

Or use a MIME attachment to store secure hashes (heck, these could even be
CRC32's if you're not too paranoid which you could pack into 5 bytes of
ascii or something) of each of the lines in the body, then a valid
signature of all the hashes at the end. 

When you reply to such a message, you'll need to reattach the hash
attachment to the reply along with some sort of translation table that
says line 20 in this message is quoted from line 502 in the original.

You'll also need some way to do quotes that won't interfere with the hash
testing... maybe using block quotes such as

:Begin_Quote
text
:End_Quote

or delete the ">" chars.  But you'll get in trouble with auto text
justifications...

i.e. reply signature mime attachment:
*Quoted Lines used: 15=234, 16=235, 17=236, etc...
*From Original Mime attachment:
*Begin body hashes
line1hash line2hash line3hash line4hash line5hash.... lineNhash
*Begin body hash signature
slkdjflskdjfjsdlfjsdlf
*End signature

Or when you quote the message, you could have the begin_quote blocks have
the line translation in them.

If you don't mind shoving HTML in the text, the begin quote blocks in the
body of the reply could include the line number.  i.e.

(using square brackets so those using HTML readers will see this.)

[Strong][QuoteLine55-69]
text_of_lines55-69_from_original_message_here.
[/QUOTE][/Strong]



Problem with this scheme:

But, then what do we do about quoted quotes from the reply of the
reply????  We could recurse the stuff through, but then deep replies will
have a large number of attachments if we chose to retain them...  Possible
solution, don't keep quoted quote signatures, or just keep the message
id's of them so they can be verified from an archive server or
something...


While you will need special mailer clients to decode the attachments and
verify the quotes, you still want some compatibility with regular mail
clients...

=====================================Kaos=Keraunos=Kybernetos==============
.+.^.+.|  Ray Arachelian    |Prying open my 3rd eye.  So good to see |./|\.
..\|/..|sunder@sundernet.com|you once again. I thought you were      |/\|/\
<--*-->| ------------------ |hiding, and you thought that I had run  |\/|\/
../|\..| "A toast to Odin,  |away chasing the tail of dogma. I opened|.\|/.
.+.v.+.|God of screwdrivers"|my eye and there we were....            |.....
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