Does my file or password get uploaded?

No. The encryption runs entirely in your browser, on your own device. The file never leaves your computer, and the password is never transmitted — it exists only in your browser's memory while the encryption runs.

What encryption does it use?

AES-256 — the same standard used in Acrobat and other professional tools. The output is a standard password-protected PDF that opens in any PDF reader: Acrobat, Chrome, Preview, and others.

What happens if I forget the password?

Because the encryption runs on your device and we never see the password, we have no way to recover it. Keep the password somewhere safe before encrypting.

How is this different from other PDF encryption tools?

Most online PDF encryptors upload both the file and the password to their servers — handing both halves of the secret to a third party. Filum encrypts entirely in your browser: the file and password never leave your device.

PDF Tools

Protect PDF

Add a password to a PDF with AES-256 encryption — entirely in your browser. The file and your password are never uploaded. No account, no email.

Frequently asked questions

Does my file or password get uploaded?: No. The encryption runs entirely in your browser, on your own device. The file never leaves your computer, and the password is never transmitted — it exists only in your browser's memory while the encryption runs.
What encryption does it use?: AES-256 — the same standard used in Acrobat and other professional tools. The output is a standard password-protected PDF that opens in any PDF reader: Acrobat, Chrome, Preview, and others.
What happens if I forget the password?: Because the encryption runs on your device and we never see the password, we have no way to recover it. Keep the password somewhere safe before encrypting.
How is this different from other PDF encryption tools?: Most online PDF encryptors upload both the file and the password to their servers — handing both halves of the secret to a third party. Filum encrypts entirely in your browser: the file and password never leave your device.

Guide

Password protect a PDF — add encryption that actually works

Add a password to a PDF so it can only be opened by people who know it. This guide explains PDF encryption, password strength, and what protection actually prevents.

Read the guide →

Frequently asked questions

Password protect a PDF — add encryption that actually works

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