Every month, I receive an encrypted Portable Document Format (PDF) file with my payslip. I can open the file for reading with my password. Without providing my password, I cannot open the file at all.
Does that mean whoever created the PDF file has access to my password in a recoverable format? Or can they encrypt the PDF by using the hash or some other non-recoverable function or pair of my password, similar to how public/private key encryption works?
The format is PDF-1.4.
Note that, as I understand it, my question is different from this question. The other question is about a PDF that can be opened with restrictions, such as restrictions to copy-paste or printing. My question is about a PDF file that cannot be opened at all before decryption. Secondly, the answers there do address that the security is weak, but do not answer my core question whether this encryption implies the creator of the PDF has access to a recoverable password (plaintext or encrypted).
Edit: I mean to ask whether it is stored on their system. I do not mean to ask whether it is stored in the file.