Secured by certificate in Acrobat DC.
If you download the PDF document with a certificate from another PC and import the certificate
Even if you delete the certificate later, it will not be secure when you open the PDF document, so anyone can see it.
I am wondering which path stores the certificate when it is imported.
I am wondering how to prevent PDF documents from being opened when a certificate is deleted.
Sorry for the delayed response and inconvenience caused. As per the description above, you want to know about the Signatures with Certificates and Security in Acrobat, Is that correct?
A certificate-based signature, like a conventional handwritten signature, identifies the person signing a document, a certificate-based signature is difficult to forge because it contains encrypted information that is unique to the signer. It can be easily verified and informs recipients whether the document was modified after the signer initially signed the document.
For detailed information, you can refer to Adobe article Certificate-based signatures, Adobe Acrobat
You can also refer to Securing PDFs with certificates, Adobe Acrobat
To find the Signature stored, you can navigate to Acrobat>Edit>Preferences>Signatures>Identities & Trusted Certificates>More>Digital IDs.
To locate the file, you can navigate to C:\Users\username\AppData\Roaming\Adobe\Acrobat\DC\Security\xxxxx.pfx.
Feel free to update this discussion for any further assistance.