[Users] nonASCII chars in OpenPGP signature

[Slavko]

Hi,

recently i got one mail which i wrote in CM rejected with message:

    550 5.6.0 improper use of 8-bit data in message header

As the message was attached in bounce, i inspect it, and only
suspicious message's headers i found is Content-Description: in OpenPGP
signature:

    Content-Type: application/pgp-signature
    Content-Description: Digitálny podpis OpenPGP

(raw translated "OpenPGP digital signature")

As one can see, it contains nonASCII char -- the "á", but the message
itself (nor that signature) has not Content-Transfer-Encoding: defined,
which AFAIK defaults to 7bit. I sign all outgoing messages for years,
and i meet this problem first time, but as it was working i never
inspect outgoing message encoding, thus i cannot tell if and when it was
changed.

The guess about signature problem is near to 100% right, as when i
resend that message not signed, it was accepted. The recipient's MTA is
postfix and i read, that postfix's 8BITMIME/SMTPUTF8 implementation is
prone to be badly configured, and target system advertise 8BITMIME
(only), thus i do not know if that matter (i never used postfix, i
only fight with similar problem with Subject: but that was not CM
related).

Now i am not sure what i want to ask ;-) But that comes in my minds is
if that signature's "Content-Description:" header was added by CM or by
gnupg? If it is added by CM, why is not 8bit transfer encoding used?

Is it possible to force message's Content-Transfer-Encoding: 8bit in
CM? Or how i can ensure, that message content fits its transfer
encoding?

regards

-- 
Slavko
https://www.slavino.sk
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