Hi Tom,

well a timestamp only may be not enough, i would strongly
suggest at least to use the free GnuPG (in case you can't use
qualified signatures with .pdf's. to detach sign the the model
file(s) etc. with your secret key and then timestamp those
detached GnuPG signature files.

Regards
Stefan

Hi Tom,

the qualified digital signature and the qualified timestamp
is done by services in Germany, which users with a German
ID-Card can sign-up. Those qualified signatures cost a little
money, for each session, also the time stamping service i
use for the .pdf. cost a little money per each session.

In case you live in Europe you have to check out what
service in your country is available to create eIDAS
conform signatures. Google for the word eIDAS regulation.

In case you live in the U.S. look for similar services
which offer qualified digital signatures or use GnuPG
and opentimestamp.org.

If you need help with GnuPG google for tutorials on
how to create a key pair and how to detach sign
files or documents. Opentimestamp with the blockchain
solution is easy. Simply visit their site and drag and drop
a file and then download the timestamp (.ots file).

In case you get stuck with GnuPG i will help you.

Regards
Stefan

a blockchain will increase the global electricity consumming!

And 3 or more billion Facebook users, each month, with their
computers and Facebook usage and WhatsApp Twitter etc.
usage and mobile phones etc. will do so too ...

Regards
Stefan

For MoI users who have a German-ID card and are interested in this
topic, I use these two services:

https://cloud.sign-me.de/signature/start
for the qualified digital signature

and
https://www.dgn.de/dgn-zeitstempeldienst/

for the timestamp.

The timestamp service can be set-up in Adobe
Reader DC, with your login-credentials, while
for the qualified digital signature you have to
upload your .pdf to sign-me.

Regards
Stefan

Thank you very much, Stefan for your very valuable tips - I appreciate that !

You're welcome Tom!

Regards
Stefan