ietf-openpgp
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Dash-escaping and the Usenet sig convention

2000-12-12 03:23:43

It has been suggested that our mail/news client offer an option to "fix
up" the Usenet sig separator in clear-signed messages to
newsgroups/mailing lists - the problem being that the "-- " gets stuffed
to "- -- " with the result that recipients' clients will no longer
recognize and strip the personal signature in response messages.

The dash-escaping leads to complaints about clear-signed messages to
some groups and some users have taken to removing the dash-escaping by
hand. Although this breaks RFC2440, (NAI)PGP clients still seem to
correctly "de-escape" the message and verify the PGP signature.

The question is, how do openPGP clients cope with such messages and what
do other client vendors think about this? Since [open]PGP clients only
need to be able to correctly parse nested ASCII-armored header lines,
and these all begin with five hyphens, it would be possible to make an
exception for lines such as "-- " when doing the dash-escaping.

Munging the "- -- " back to "-- " does seem to yield benefits in inter-
operability (for the sig-sep convention) and acceptability of PGP-signed
messages, but it is important that it doesn't break inter-operability
between PGP clients.

Should RFC2440bis be updated to mention this? Do any existing clients
fall over by spotting that some lines are escaped at the "wrong" depth?

-- 
Ian Bell                                           T U R N P I K E