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How to validate a signature on a digitally signed document

Guidance on how to validate a signature on a digitally signed PDF export certificate or document received through this service.

You only need to validate a digital signature once per device. Once you have added DBT as 'trusted', all future documents will automatically be validated on that device.

Before you start

You will need:

• your export certificate
• a Windows or Mac computer or laptop - you cannot validate a digital signature using a mobile phone
• the latest version of Adobe Acrobat Reader installed

Validating the digital signature

If you need to validate the digital signature you will see a message that says 'At least one signature has problems' at the top of the document.

Follow these steps to validate the digital signature:

1. Open the PDF in Adobe Acrobat Reader.
2. Right-click (or control-click) the digital signature and select Show signature properties.
3. In the 'Signature properties' window, select Show signer's certificate.
4. In the 'Certificate viewer' window, select the Trust tab.
5. Select DBT in the left-hand panel and select Add to trusted certificates.
6. Select OK on the pop-up message to change the trust settings.
7. In the 'Import contact settings' window, make sure the 'Use this certificate as a trusted root' checkbox is ticked and select OK.
8. In the 'Certificate viewer' window, select OK.
9. In the 'Signature properties' window, select Validate signature. The message at the top of the window will change from 'Signature validity is UNKNOWN' to 'Signature is VALID, signed by DBT'.
10. Select Close.

The message at the top of the document should now say 'Signed and all signatures are valid'.

Learn more about how to validate digital signatures (Adobe Help Center).