Slightly OT - i need the proper wording for a signed document

Stefan Claas stefan.claas at
Fri Nov 2 12:53:31 CET 2018

On Fri, 2 Nov 2018 12:20:43 +0100, Wiktor Kwapisiewicz wrote:
> On 02.11.2018 10:53, Stefan Claas wrote:
> > Simply one can use a time stamping service, based on blockchain
> > technology. I can then time stamp the .pdf. and put also a
> > statement in the .pdf that the file is timestamped and don't must
> > worry in the future if one MITM would try (and why?) to alter my
> > documents.  
> PDFs can be also timestamped when signing with standard RFC 3161 [0]
> timestamping service.
> Here's one example:
> But there are numerous free RFC 3161 timestamping services.
> Of course that's not the same as blockchain, but it's already
> supported by numerous tools (like Adobe Acrobat).

> [0]:

Hi Wiktor,

thanks a lot! Now this is awesome... i just timestamped my already
signed .pdf with Adobe Reader DC and this does not invalidate my
qualified signature, when saving the document again! :-) I must admit
i did  not know this.



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