GnuPG - signed Telefax communication

[Стефан Васильев]

Ángel wrote:

> On 2022-01-14 at 16:42 +0000, Стефан Васильев wrote:
>> Hi all,
>> 
>> If people have a modern Telefax machine, have you ever
>> tried out to send a GnuPG signed Fax?
>> 
>> I was thinking about the following:
>> 
>> One prepares his message in the following way:
>> 
>> ---begin message---
>> 
>> Message.
>> 
>> --end message---
>> 
>> Then saves the message, detach signs it and converts the
>> detached signature as QR-code which is put then also on
>> the Fax document, while the receiver then OCR scans the
>> document and decodes the QR-code.
> 
> 
> What's wrong with simply using a PGP clearsign signature?

I tried in the past to OCR scan armored GnuPG payloads, but
it introduced errors in some characters. And in case this
happens to others, how can users not having the original digital
document correct then errors?

If this works 100 percent reliable for you, you could explain the
required (standard) settings for printed/scanned documents.

Regards
Stefan