Daiki Ueno <ueno@unixuser.org> writes:

>>>>>> In <87ps7k9anj.fsf@lrde.org> 
>>>>>>	michael@cadilhac.name (Michaël Cadilhac) wrote:
>>   	  (setq process
>>   		(apply #'start-process "pgg-gpg" buffer pgg-gpg-program args)))
>>         (set-default-file-modes orig-mode))
>> +     (set-process-coding-system process 'utf-8)
>
> At least, this change will cause a problem on encryption, if the
> plain text is encoded in non-UTF-8 encoding.

You're right, sorry.  Maybe the following?