Why is digital signature "not validated" when sent to another person

When I send a document with my digital signature to a user that only has adobe reader, the signature will say "not validated." How can I make my digital signature valid for reader users?


Chris Cole


4 Answers

Have you sent them the public version of your digital certificate used for signing the PDF or a accessible link to that certificate.

The digital signature and associated certificate are need to verify the PDF has not been changed since it was signed.


George Kaiser   

I am brand new to adobe writer 10.0- When I send the digitally signed document to a coworker sitting next to me, and they click on the signature, the following message pops up:

Signature validity is UNKNOWN

-The Document has not been modified since this signature was applied.

-The signer's identity is unknown because it has not been included in your list of trested identities and none od its parent certificates are trusted identities.

Is this what will normally be shown if I send a digitally signed document to another individual? It makes the signature seem less trustworthy...


Chris Cole   

"-The signer's identity is unknown because it has not been included in your list of trusted identities and none or its parent certificates are trusted identities" indicates your co-worker needs to add something to his copy of Acrobat/Reader. What he is missing a certificate and only you can provide him with a copy of the certificate you created to sign the PDF. After you send him or make available a copy of the certificate, then your coworker will need to import that certificate into his copy of Acrobat.

Look in the Help documentation for Acrobat and Reader for more information.




George Kaiser   

Digital signatures with Acrobat are very difficult to get your head around to start with, but if you want your PDF signature to be valid on your co-worker computer, as mentioned you need to supply them with your Public certificate. To do this you need to export it out as an .fdf file, if in Acrobat X, choose Edit – Protection – Security Settings, select your ID that you used to sign the PDF with and choose Export, you can then either save it to disk, or directly email your certificate, get your co-worker to double click it in Adobe Reader and follow the prompt, when you see Set Contact Trust, select it and check Use Certificate as Trusted Root. Then click OK. Now open the PDF and it should now be valid.

I definately recommend reading the help files though, as this will give you a better understanding of Signatures, Digital IDs and the different kind of certificates.

Hope this helps?


Sean Mitchell   


Please specify a reason: