We have 2 versions of Acrobat, 9 and XI. We are using e-certificate from Hong Kong Post (HK government). Each certificate has a validity of 3 years, after 3 years a new certificate will be assigned to the owner.
We have a user who used her e-certificate to sign a document in 2013, her certificate, back then, is vaild til 2015. When the old ceritficate past the last vaild date, she got a new one from Hong Kong Post.
When we try to open documents she signed in 2013 with Acrobat 9, it said the signature has expired and the little yellow triangle shows up when we validate the signature. When the same documents are opened by Acrobat XI, it said the signed signature is valid and when click into the detail, it said Signature is not LTV enabled and will expired after 2015.
I would like to know why it show the signature is not valid in Acrobat 9?
When I open a signed PDF whose signature is not LTV enabled, I get the same information in the signature properties in Acrobat 9.5.5 as I do in Acrobat XI (and in Acrobat DC, too).
In all cases, I have trusted the signer's certificate or a certificate in the signer's certificate chain.
In both versions, I see a yellow warning triangle (and not a red invalid X).
And I see the following Signature Validation status in both versions:
Signature validity is UNKNOWN.
- The Document has not been modified since this signature was applied.
- The signer's identity was valid when it was issued, but no revocation checks could be made to validate the identity at this time.
Again, I obtain the above status with Acrobat 9 Professional 9.5.5 and Acrobat XI Professional 11.0.18.
There may be other factors that are causing different results.
One might be whether the signing certificate or another certificate in the chain has been manually trusted or trusted via an AATL download.
You may also want to confirm the signing application. You can determine the application used to apply a signature by clicking the Advanced Properties… button in the Signature Properties dialog.
Without having a copy of the PDF, that’s about all the info I can provide.