Password Protect PDF
Add a password and AES encryption to a PDF, or remove a password you already know — free and entirely in your browser. Your file and password are never uploaded.
How to password protect a PDF
- Add your PDF. Drag and drop it onto LambiPdf, or click “Choose files.”
- Open the Encrypt tool, set a user password (needed to open the file), and choose whether to allow printing, copying, or editing.
- Encrypt & save. Your protected PDF is created on your device and downloaded.
Remove a PDF password
Already know the password? Add the file — LambiPdf will ask for the password to open it — then use the Decrypt tool to save an unprotected copy.
Encrypt PDFs privately
Because encryption and decryption run in your browser, neither your document nor your password is ever sent to a server. It's a fast, private way to lock a sensitive PDF before sharing it — no account, no watermark. LambiPdf uses AES-128 encryption for broad compatibility with PDF viewers.
More free PDF tools
Protect PDF — FAQ
Is my password or file uploaded?
No. Encryption and decryption happen entirely in your browser; nothing is sent to a server.
What encryption is used?
AES-128 — strong encryption that's supported by virtually all PDF viewers, including browsers and mobile apps.
Can I remove a password from a PDF?
Yes, if you know it — open the file with the password, then use the Decrypt tool to save an unlocked copy.
Is this free?
Yes — free, no sign-up, no watermark.