Is a PDF Password Secure?
A PDF password (AES-256 when set properly) blocks opening or editing, but weak passwords and old formats are breakable, and "permissions" passwords are easy to remove. Treat it as a speed bump, not a vault.
What a password does
- Open password — required to open the file (encrypts content)
- Permissions password — restricts printing/editing (easy to bypass in many tools)
Where it fails
- Weak or reused passwords can be brute-forced
- Old "40-bit RC4" PDFs are trivially breakable
- Permissions-only passwords are often removable in seconds
What we recommend
A password is fine for low-stakes sharing. For IDs, tax returns, or contracts, do not rely on it alone — and do not upload the file to a server to "add a password." Keep it local. PDFzen processes files in-browser and never uploads them, which removes the transport risk even if it does not add encryption.
Honest note: to actually add a strong open password, use a desktop app (Acrobat, PDF24) or a local tool built for encryption. Browser libraries we use do not write real encryption, so we do not offer a "password" tool — we would rather be honest than mislead.
FAQ
Is a PDF password secure?
A strong AES-256 open password blocks casual access, but weak passwords and old formats are breakable.
Are permissions passwords safe?
Not really — print/edit restrictions are often removable in seconds.
How should I share sensitive PDFs?
Avoid uploading; keep files local and use a real encryption tool, not just permissions.