Password-protected PDF (content uninspectable)

Unlike a permission/DRM-sealed PDF that opens with an empty user password (billing statements, signed invoices — the reader decrypts transparently and the analyzer can inspect the content via qpdf), this document requires a real user password to open, so every string and stream is cryptographically inaccessible to static analysis. This is a recognised malware-delivery evasion: the open-password is supplied in the phishing e-mail body so the recipient can open the file while automated AV/sandbox pipelines cannot. It is not malicious on its own (confidential documents are also password-protected), but it means the content was not inspected and should be treated as unknown, not clean.