Ihor Radchenko <yantar92@posteo.net> writes:

> "Christopher M. Miles" <numbchild@gmail.com> writes:
>
>> - [X] Then I check out Emacs source code file "epg.el" & "epa.el" file
>>   git log. -> have not found obvious gpg command-line options related to
>>   the problem. One small possible commit might be
>>   "82388dff8ed006cecb65ea7a4afd8667ec44b5e3".
>
> One of the reddit comments mentioned that the newer gpg hangs when not
> provided input. If this is true, I notice that `epg-start-encrypt' first
> calls (epg-wait-for-status context '("BEGIN_SIGNING")) and only then
> sends the buffer string for encryption (process-send-string).

Indeed, I'm superised by myself that haven't notice this steps.

(epg-wait-for-status context '("BEGIN_ENCRYPTION")), it suspended and
wair for "BEGIN_ENCRYPTION" input. But The real input is from bellowing
(process-send-string (epg-context-process context) (epg-data-string plain)).

Finally found the reason in Elisp code.

I will send this update info to Emacs bug report.