How do I add a password to a PDF?

Drop your PDF onto the tool. re;file labs checks whether it is already encrypted and opens a password dialog. Enter and confirm a password, then click "Lock PDF". Your browser downloads the protected file.

How do I remove a password from a PDF?

Drop your password-protected PDF onto the tool. A password dialog opens automatically. Enter the current password and click "Unlock PDF". The downloaded file opens without any password prompt.

What encryption standard is used?

Locking uses AES-256 under the PDF 2.0 standard (revision 6). AES-256 is the same cipher used by governments and banks. All permissions are preserved, meaning authenticated users can print, copy, and edit the document normally.

What happens if I enter the wrong password?

Nothing! No file is downloaded. An error message appears letting you know the password was incorrect. Just re-enter the correct password and try again.

Can I recover a PDF if I forgot the password?

No. AES-256 encryption is designed to be unbreakable without the key. This tool cannot brute-force or bypass passwords. Keep your passwords in a password manager.

Are my files or passwords sent to any server?

No. Everything runs locally in your browser using a Rust library compiled to WebAssembly. Your files and passwords never leave your device. There is no upload, no server, and no logging.

Is there a file size limit?

No fixed limit. Processing happens in your browser tab using available device memory. Most documents, including large ones, process in under a second.

Can I lock a PDF that is already password-protected?

Yes. Drop it in and the tool detects the existing encryption and warns you. Locking will replace the existing password with the new one you set.

Does locking a PDF prevent editing or printing?

No. This tool sets an open password (required to view the file) but grants full permissions once unlocked. Restricting editing or printing separately is not currently supported.

Will the locked PDF work in all PDF viewers?

AES-256 (PDF 2.0) is supported by Adobe Acrobat, Preview on macOS, Chrome, Edge, Firefox, and all modern PDF viewers. Very old viewers (pre-2017) may not support PDF 2.0 encryption.

Also try the PDF Editor

PDF Password

Drop a PDF. re;file labs detects whether it is locked or not and prompts for the right action. No uploads, no data sent to external servers.

Click to upload or drag and drop

Drop a PDF to lock or unlock it

How it works

Browser-only PDF encryption

Drop a PDF and re;file labs reads its encryption status instantly. For unprotected PDFs, it prompts for a password and encrypts using AES-256 via a Rust library compiled to WebAssembly. For protected PDFs, it prompts for the existing password and decrypts using the same library. Both operations complete in your browser tab. No file is ever sent to a server, and no account is required.

Use cases

When to password-protect a PDF

Contracts and legal documents

Lock signed contracts, NDAs, and agreements before emailing. Only recipients with the password can open them.

Exam papers and answer keys

Distribute locked exams to prevent early access. Unlock and share the answer key after the exam ends.

Financial reports

Add a password to salary sheets, audit reports, or invoices before sharing with clients or stakeholders.

Personal documents

Protect scanned passports, tax returns, or insurance documents stored in cloud drives or sent by email.

FAQ

Common questions

Everything you need to know about PDF password protection.