Where does encryption run?

On your device. We never receive the file or the password. If the file is already encrypted, unlock it first.

Yes — free, no watermark, no account.

How should I share the password?

Send the password on a different channel from the file — a phone call or chat, not the same email thread.

Short answer

Encrypt PDF runs entirely in your browser. Password-protect a PDF so it cannot be opened without the password. No account, no watermark, and the file never leaves your device.

Stays on your device·No upload·No account·No watermark·Offline after install·How it works Methodology Privacy

Encrypt PDF Online

Password-protect a PDF so it cannot open without the password — free and local.

Drop a file or browse

Drop an unlocked PDF — add a password locally (AES). Already encrypted? Unlock first.

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About this tool

Encrypt PDF online for free — password-protect a file so it cannot be opened without the password. Encryption uses standard PDF crypto in your browser — we never see the file or password.

If the file is already encrypted, unlock it first, then encrypt again with the password you want recipients to use.

How to use Encrypt PDF Online

1Open an unlocked PDF.
2Set a password you will remember.
3Encrypt and download the protected file.

You need

An unlocked PDF
A password you will remember

Common use cases

Protect a confidential PDF before emailing it.
Add an open password after redacting sensitive pages.
Students or freelancers locking drafts before sharing externally.

Frequently asked questions

Where does encryption run?
On your device. We never receive the file or the password. If the file is already encrypted, unlock it first.
Is encrypt PDF free?
Yes — free, no watermark, no account.
How should I share the password?
Send the password on a different channel from the file — a phone call or chat, not the same email thread.