I'm trying to sign PDF files. While FoxIt it happy with them, Reader is not. There are actually several issues.
The main one is that Reader is telling me "The document has been altered...". It provides no clue regarding the reasons for that. Since Foxit it happy, it indicates that the problem is not with the hash/digest/encrypt process but with something else.
There is a 2nd issue that might be related. Reader is telling me that the signing certificate is "the selected certificate path has errors not valid for usage". Again, no explanation is given.
Any help will be appreciated. I tried several paths: certificate syntax errors, certificate policies, missing extensions but I can't seem to find the issue. I'm attaching the document plus two certificates: the signer's one and the CA's one (certication path is just 2 items).