I'm changing the subject of my replay, to denote that UI think that this is a
somewhat separate issue from whether the preference notation packets should
be added to RFC 2440bis.
On Sunday 16 January 2005 10:58 am, Simon Josefsson wrote:
I believe that inline/partitioned should never be recommended by any
RFC, at least without more specification. I believe RFCs should
clearly recommended against its use in e-mail because we have PGP/MIME
that, to my knowledge, solve all known problems, if implementors were
to actually support it. RFC 2440 does this correctly.
A question was raised earlier in this WG why 2440bis do not include
the same text, but I'm not sure there was consensus declared.
I'd be disappointed if IETF approved a standard that implied use of
PGP in e-mail in any other way than PGP/MIME.
Here's my issue with PGP/MIME (RFC 3156) The PGP/MIME standard defines
placing an email-specific Content-Type header inside the section covered by
the signature, making verification of binary content difficult outside of a
mail client. Further, almost all implementations generate a single signature
across all parts, generating a signature for the entirety of the
email-specific MIME structure, and not signing individual attachments. I
believe that this is a serious flaw in RFC 3156.
One of the users of the GPG Plugin for Squirrelmail the I am the primary
implementor of is human rights workers (via the CryptoRights Foundation).
For evidentiary reasons in this implementation, it is critical that each
binary attachment (documents, pictures, whatever) have independently
verifiable signatures. The 'partitioned' method accomplishes this, by
encrypting/signing each part, so that each part is independently
decryptable/verifiable, even outside of an MUA. I think that independent
verification of a signature on each part, and a signature across the whole,
are a feature that should be required of any email implementation (although
this is a bit out of scope for the current discussion of preference
notations).
If you are seriously proposing to make inline/partitioned a standard
scheme for PGP in e-mail, you should describe how it should be
implemented. I have experience with the inline style, and
non-deployed experience with the "partitioned"-style. The problems
that need to be addressed to make this a serious alternative is RFC
1991-compatibility wrt dash-escaping, interaction with non-ASCII (both
in bodies and PGP headers), trailing white space interaction with
format=flowed, interaction with QP and '-' and '=' in the PGP armor.
Many MUA's have chosen to not support inline or partitioned methods of
Encrypting/Signing mail content. This seriously limits interoperability, and
I think that this needs to be addressed in RFC 2440bis (because that is what
is under discussion now) and in any future revision of RFC 3156.
The problems that need to be addressed to make this a serious
alternative is RFC 1991-compatibility wrt dash-escaping,
interaction with non-ASCII (both in bodies and PGP headers),
trailing white space interaction with format=flowed,
interaction with QP and '-' and '=' in the PGP armor.
I do not believe that support for partitioned in the notation packet implies
RFC 1991 compatibility. We have decided that 2440bis will obsolete RFC 1991,
if I recall the concensus of the group correctly. We have also otherwise
addressed dash-escaping and trailing whitespace issues. I think that a
'partitioned' scheme is the only option currently available to implementors
who require independent verification of each part, as well as verification of
the whole.
Regards,
- Brian