Re: PGP support

[sascha@meta-x.de (Sascha Lüdecke)]

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Josh Huber <huber@alum.wpi.edu> writes:

> Per Abrahamsen <abraham@dina.kvl.dk> writes:
>
>> Actually, I can't.  Probably because of 
>>
>>           X-MIME-Autoconverted: from quoted-printable to 8bit by
>>           sheridan.dina.kvl.dk id WAA23581
>>
>> Would such convertions affect PGP?
>
> Well, did the message verify for you?

This message is in the 'old'format.  You should be able to verify it.

>
> I suspect that the message is signed first, and then encoded QP,
> which would explain the QP encoding of the PGP headers.

Thats exacly what mml1991 does.  Since the message body can contain
non 7-bit characters, one has to protect them from certain MTAs.
mml2015, which I took the code from, does that by QP encoding the
message body and signing afterwards.  This works fine, since the body
is a separate MIME part.

As far as I can guess/see there are two options with old PGP style:

   - using ASCII armouring as protection, which renders the messages
     unreadable without PGP

   - protecting the 8bit characters after signing.


RFC 2045 (Multipurpose Internet Mail Extensions, Part one) states on
page four (ASCII version), talking about MIME headers:

    ...

    (3)   A Content-Transfer-Encoding header field, which can be
          used to specify both the encoding transformation that
          was applied to the body and the domain of the result.
          Encoding transformations other than the identity
          transformation are usually applied to data in order to
          allow it to pass through mail transport mechanisms
          which may have data or character set limitations.

    ...




RFC 2049 (Multipurpose Internet Mail Extensions, Part five) states:

   A mail user agent that is MIME-conformant MUST:

    (1)   Always generate a "MIME-Version: 1.0" header field in
          any message it creates.

    (2)   Recognize the Content-Transfer-Encoding header field
          and decode all received data encoded by either quoted-
          printable or base64 implementations.  The identity
          transformations 7bit, 8bit, and binary must also be
          recognized.

          ...

Thus I assumed the QP transfer encoding is safe.  Unless your
recipient doesn't have a MIME capable mail tool.

> FWIW mutt does not do this.  Does Outhouse Express support PGP
> signed messages that are QP encoded like this?

I haven't tested how it works with other mail tools beside Gnus yet.
Unfortunately the reason for hacking mml1991 together, an OutOfLuck
user who coudln't make use of PGP/MIME, refused to further test it --
installation of plugins seemed to be too compilcated.

Best regards,
Sascha

- -- 
Nothing is free in this world, so go get some nothing before they
charge for it!
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