Issue
I received a PDF that has a banner at the top saying, "At least one signature is invalid". How do I fix this error?
Explanation
Adobe does not recognize the certificate used for one or more of the signatures in the PDF. Commonly, this is because the signer used the UTD-issued certificate they got by following CKCS #180: Digital Certificates. If you are the recipient of a PDF that was signed using a UTD-issued certificate, you will need to "trust" UTD's main certificate (the one all individual UTD certificates are validated against) in Adobe.
Trust the Certificate
- Click the Signature Panel button in the banner where the error is.
- Then, click on the Signatures iconin the left-hand sidebar.
- You will be able to see all the signatures which are causing the issue. However, you need to validate only one signature to remove this error.
- To do that, expand a signature and then the Signature Details section by clicking the arrows adjacent to them. Then, select Certificate Details.
- Select the row above the one with a warning sign in the new window. The row should state "The University of Texas at Dallas RSA".
- In the window, navigate to the Trust tab and select Add to Trusted Certificates.
- Select OK in the first dialog box after reading the instructions displayed.
- In the Import Contact Settings window which opens next, check the option "Use this certificate as a trusted root".
- Select OK to close all windows and finish the task.
- Close the document and reopen it. You should not get the error again.