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Digital Sign PDF with digital hash

I’m newbie with aspose.pdf, and I wonder if someone could explain if it is possible to digital sign a pdf with a extenal digital signed hash.
Our web application will digital sign pdf, with a 3rd party Entity.
The all process will be more or less like this

  • 1º Choose a document, submit to the server
  • 2º In the server we compute document SHA256 hash, and send to the 3rd party.
  • 3º The 3rd party send a sms token to the customer mobile
  • 4º The customer, submit a form with the token,
  • 5º After the 3rd party validate the token, return a the document hash digital signed.
  • 6ª After that we have to bind the hash digital signed to the document.
    It is possible to do this?


At the moment, Aspose.PDF supports signing PDF documents using .pfx certificates and smart card. We need to investigate whether signing the document with digital hash is feasible or not. For the purpose, we have logged a ticket as PDFNET-48741 in our issue tracking system. We will further investigate it and let you know about our feedback as soon as it is resolved. Please have patience and give us some time.

We are sorry for the inconvenience.


At the moment, you can sign a document and calculate its hash. But cannot store this value within the document because it changes the hash. You may store hash values in a separate file. Can you please share some extra information about your requirements so that we can further proceed with investigation?