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Signature is invalid - SwissSign

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Posted: 08/31/2015 14:53:15
by Philipp Egger (Basic support level)
Joined: 08/31/2015
Posts: 1

Dear Support Team,

I am evaluating the PDF SecureBlackBox for signing PDF documents.

I used the demo C# project TinySigner that you provide with the evaluation files together with a USB token from swisssign.

When signing the PDF I get a success message from the TinySigner tool (I had to give the password).

But when I open the signed PDF file in the Acrobat Reader DC 2015 I get an error message with a red cross: "Signature is invalid"

Further messages are:

There are errors in the formatting or information contained in this signature
Signer's identity has not yet been verified
Signing time is from the clock on the signer's computer.

By the way, I passed the TSA URL: http://tsa.swisssign.net (but still get the message that the clock on the signer's computer was used).

I have put the signed PDF in a text file in the attachments.

The first file is the SecureBlackBox output. The second file is a valid signature in the PDF signed with the SwissSign tool.

Any ideas what I am missing here?

Best Regards,


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Posted: 08/31/2015 15:39:51
by Ken Ivanov (EldoS Corp.)

Hi Phil,

Thank you for contacting us.

Unfortunately, the files were apparently corrupted by the text editor so we can't check what's wrong with them. We inspected the signatures though, and both made by SBB and SwissSign look just fine. There are some differences in them (the one made by SwissSign uses SHA256 as a hash algorithm, while the one made by SBB uses SHA1, to be exact). Yet, these differences should not affect the verifiability of the signature.

I would kindly ask you to try to send us the files again. I have created a ticket for you in Helpdesk, our private and secure online ticketing system. It would be great if you upload both files there.





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