PDF guides
Protect PDF vs Unlock PDF: What Each One Does
Protect PDF and Unlock PDF do opposite things. This guide clarifies which one you need and what to do if your file already has a password.
Ready to try the tool this guide describes?
Protect PDF: adding a password
Protect PDF takes a PDF that currently has no password and encrypts it with AES-256, so it can only be opened with the password you choose. It is for documents you want to lock down before sharing.
Unlock PDF: removing a known password
Unlock PDF is the reverse workflow: given a PDF that already has a password you know, it removes that protection so the file opens freely. This tool is planned but not yet available.
If your PDF already has a password
Protect PDF does not currently support re-protecting a file that is already encrypted — it treats an already-password-protected PDF as unsupported input. Remove the existing password with a password-removal tool first, then run the unprotected file through Protect PDF if you want to set a new password.
Protect vs Unlock a PDF FAQ
- I have a password-protected PDF and want a different password. What do I do?
- Remove the existing password first, then use Protect PDF to add the new one. Protect PDF does not re-encrypt an already-protected file directly.
- Is Unlock PDF available yet?
- Not yet — it is on the roadmap. Protect PDF (adding a password) is available now.
- Does Protect PDF work on a PDF that already has a password?
- No. An already-encrypted source PDF is treated as unsupported input.
- What if I don't know the existing password?
- Neither Protect PDF nor the planned Unlock PDF can bypass a password you don't know — that is the intended behavior of PDF encryption.
- Can I add a new password without knowing the old one?
- No. You need the current password to remove existing protection before a new one can be applied.
Related guides
- How to Protect a PDFAdd a password to a PDF in your browser: choose a password, confirm it, and download an AES-256 encrypted copy that only your password can open.
- AES-256 PDF Encryption ExplainedUnderstand what AES-256 encryption means for a password-protected PDF, how it compares to older methods, and why a lost password cannot be recovered.
- How to Watermark a PDFStamp text or an image watermark onto a PDF in your browser: choose a mode, position, opacity, and page range, then export a stamped copy.