of the inSign signature

Technical understanding of the electronic signature

You have received an electronic document processed with inSign containing digital signatures? Please find here everything you need to know.

Are the digital signatures legally binding?

inSign signatures correspond to the so-called “advanced electronic signature”, AES, under European eIDAS regulation. All biometric data contained in the document verify whether a certain person has provided a certain signature.

How can I find out who really signed?

For a simple electronic signature (SES), proof is difficult. It is hardly possible to determine whether the signature in question was placed by a specific person.

With the advanced electronic signature (AES), biometric data is recorded in addition to the signature image. A handwriting expert can analyze the signature’s metadata in order to assign it to a person by means of an expert opinion.

With the qualified electronic signature (QES), identification takes place before the signature. This means that the identity of the signatory is certain at the time of each signature.

How can I find out which key was used to encrypt the biometric data?

How can I find out which key was used to encrypt biometric data? Since December 2020, information and metadata about the creator of the key are stored in the PDF document. To retrieve this information, start by opening the document in Adobe Reader. Then click on a signature field and then on “Signature Properties”.
signature properties in PDF

How do I recognize if my document has been tampered with?

Opening your document using a corresponding application (e.g. Adobe Acrobat Reader), various metadata in addition to the actual content can be viewed. Please ensure that the document and all revisions have been signed with a certificate. This verifies that the document’s contents have not been subsequently modified.

If your document has been tampered with after signing, it gets marked by a red X and the following message
“The signature is not valid. After signing the document has been altered or tampered with.”
signature validation status invalid
signature validation status valid

How to recognize a genuine inSign document?

It depends how you open your PDF document.

Adobe Reader

Open your document in Adobe Reader. Click the signature field, then “Signature properties” followed by “Display signatory’s certificate”. The “Summary” tab should display any of the following certificates:

Foxit Reader

If you use “Foxit Reader”, you can proceed in the same way as you would using Adobe. Click the signature field, then “Signature properties” followed by “View certificate”.


In Nitro the certificate can be viewed by clicking the signature field, selecting signature properties and clicking “View certificate”.


Unfortunately, the Chrome, Firefox, Edge and Safari browser viewers cannot display any certificate information. Therefore, it cannot be verified if the document is a genuine inSign document.

Please note: All documents containing a certificate issued before 06/12/2019 will be marked with the status “UNKNOWN”. Most documents that contain a certificate issued after 12/06/2019 will be marked with the status “VALID”. The status depends on whether the certificate used is based on a ROOT certificate listed on the EUTL (European Trust List). The biometric data is stored in the PDF document correctly in both cases.

What are the advantages of digitally signed documents?

A document containing digital signatures will be existing in its original quality in years to come. Ink-on-paper signatures, however, fade over time. This makes it nearly impossible to provide evidential value by subsequent digitization of the signature, i. e. by scanning and destroying the original.
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