Subject: Re: Multiple OpenPGP messages per file: legal or not?

From: <[email-masked]>
Date: Mon, 08 Oct 2007 11:00:04 -0400

On Mon, 08 Oct 2007 09:27:27 -0400 Rachel Willmer 
<[email-masked]> wrote:
>On 08/10/2007, Ian G <[email-masked]> wrote:
>> Well, like I say, the spec has to stop somewhere.

>... if 2 apps supporting the same standard (and I mean OpenPGP in 
>its
>wider sense, not just RFC2440) which support the same set of
>algorithms and suitable keys, can't actually talk to each other, 
>then
>I'm not sure what the point of the standard is.

part of the issue is that while there is an open pgp standard,
there are applications that are more liberal in what is 
'acceptable',
and such differences in 'acceptance tolerance' may allow for one 
application to be able to decrypt a message while the other cannot

here is one such trivial example of an encrypted message, and the 
keypair

?;^)-----BEGIN PGP MESSAGE-----
comment: encrypted to aaaa1

qANQR1DBwEwDfcQnSvkBVJYBCAC7wNF8JslX1QT3OOOnzGSEfb5+kqjBknsboyVi
g6vM0nGAhv8Gyr6kbgBU4tEd9naO046t5Nrn41m5o8uIaGqCnSIsqPkazHKL3ksn
4eUvKRdvib+/rNMRzLmHjIOW+qiAOekzKcx2qMRJjcgjglZHIybHRTbvixD8rYFn
GOs0pg9dQU3xYaHy5i7GCbg6K+N2CBXtBz9QTo4pU6mj6iUyGswO2xu0fqxmfJmi
z+SjfhETu/BzEhQJH5X8JCoPMh33Q/FHMtSkTYj9NioFHE60fknPWg69afIYip+Q
8L7TTT9ZAm9yzq8L9QJUQttZ1Pu5zXwnf9PfIQ5n9ErmDwHm0kIBuaX+JW6I3JVO
qdb9J0GXfqAjOIFQqWjWUG1n2PftBy4teKKRP6BvUzeC8OyIRQRVp4HYrkHpjKMj
FDqcahUq6Rg=
=nTQP
-----END PGP MESSAGE-----

PGP is tolerant of the question mark and smiley in front of the 
armor heading, and decrypts it

GnuPG considers it an improper armor heading and stops attempts at 
further decryption

(to be fair,
PGP does not generate the encrypted message with the altered armor 
heading,
but in the past, has generated long statements in the version line, 
which did cause 'improper heading' error messages when wrapped to a 
separate line)

so,
a possible way of dealing with this,
might be to have applications have a 'default mode'
where whatever is generated is 'within the letter of the law' of 
the standard,
and an 'expert mode'
to allow for special features that might be convenient to a user or 
co-application,
with the understanding that other applications might not be able to 
process messages done in that mode

(btw,
have lots of examples of similar 'oddities' in case anyone is 
interested)

vedaal 

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