Signature invalid

[Prashanth_SN]

In PDF file, signature shows as invalid. Please guide how to resolve this issue.

[MikelKlink]

If that signature had originally been valid at all, the file meanwhile has been changed somehow which broke the signature. Such a change may have been an explicit manipulation of the file or it may have been the result of damage in the file caused by inappropriate storage (e.g. storage in a database field configured for text content).

No matter how that change came up, to resolve the issue you need to ask the source of the file for another, not broken copy of the file. 

PS: Another option could be that the signature had been broken from the start. In that case you should inform the signer. 

[Prashanth_SN]

Again I have downloaded the file from original source but still it shows Signature invalid. When we click on the Signature invalid option, it shows "Error during signature verification." Signature contains incorrect, unrecognized, corrupted or suspicious data. Support Information: SigDict /Contents illegal data.

[MikelKlink]

Again I have downloaded the file from original source but still it shows Signature invalid.

Then you should contact the original source, inform them, and ask them for further steps. There are two major possible causes:

• The original source currently has a problem and produces invalid signatures.
  In this case you can hope they recognize their mistake and fix it.
• The signing scheme used by the original source is non-standard and you are expected to use a different validator than Adobe Acrobat to validate.
  In this case you can hope they'll point you towards a tool that validates their custom signature scheme.

[S. S]

Hi @Prashanth_SN,

Hope you are doing well. Sorry for the trouble, and the delayed response.

In case you are still looking for a solution, we would like to investigate further.

Would you mind sharing the file with me over a private message? This will be purely used to investigate and later discarded once we are done with testing.

To send a private message, click on my profile name followed by the blue "Send Message" button.

-Souvik