🔐 Protect PDF with Password

User password (also called "open password") is required to open the PDF at all — without it, the document cannot be viewed.

Owner password (also called "permissions password" or "master password") unlocks the PDF without restrictions. When someone opens the PDF with the user password, the permission restrictions still apply. When they open it with the owner password, all restrictions are lifted.

Most people use the same password for both. If you want stricter control, use different ones.

AES-256 (recommended) — the strongest option, used by banks and governments. Supported by every PDF reader released after ~2006.

AES-128 — still very secure, slightly better compatibility with older software (Acrobat 7+, 2004).

RC4-128 — legacy encryption. Only use it if you need compatibility with truly ancient PDF readers. It has known weaknesses and should be avoided otherwise.

No. PDF encryption is designed so that without the password, the file's content is mathematically unrecoverable. There is no "reset" option, no recovery email, no backdoor. If you lose the password, you lose access to the document's content permanently.

Always write your passwords down in a password manager before locking a document you care about.

Partially. The permission flags (no printing, no copying, etc.) are part of the PDF spec and are respected by mainstream PDF readers. However, they aren't cryptographic — a determined person with a tool like qpdf, pdftk, or advanced software can remove the permissions without knowing the password.

The actual encryption (the user password) is what protects the content — that's mathematically solid. Treat permission restrictions as strong deterrence rather than absolute control.

Yes. Modern browsers' built-in PDF viewers support AES-encrypted PDFs with password prompts. When you click an encrypted PDF in a browser, it will ask for the password before displaying the content.

No. Everything happens in your browser. The password you type is used locally by the encryption library and never transmitted anywhere. You can verify this by disconnecting from the internet after the page loads — the tool will still work.

No. If the PDF is already encrypted, you need to remove the existing password first using the Unlock PDF tool, then re-protect it with a new password.