Protect PDF
Upload a PDF below, choose a password, and click Protect PDF to encrypt it. Anyone opening the result will need the password before they can read it. Optionally set a separate owner password that controls permissions. The original pages are kept exactly as they were — only the encryption layer is added. Everything happens locally in your browser — your file and password never leave your device.
Read the guide: How to password-protect a PDFInput
Output
Processed locally in your browser — nothing is uploaded.
How the Protect PDF works
- Your PDF is read into the browser and encrypted with qpdf, a PDF engine compiled to run locally via WebAssembly.
- It's re-saved with 256-bit AES encryption, using your password as the user password required to open the file.
- Optionally a separate owner password is set to control permissions like printing and copying.
- The result is a standard encrypted .pdf file that can't be opened without the password, ready to download and share.
Useful tips
- Use a strong password — at least 8 characters, mixing letters and numbers; a 12-character passphrase is even better.
- Share the password through a different channel than the file itself.
- There is no recovery — store the password somewhere safe before sharing the protected file.
Frequently asked questions
Is my PDF or password sent to a server?+
No. The entire encryption runs in your browser using JavaScript. Your PDF and your password are never uploaded to any server, so it is safe to protect sensitive documents like contracts or invoices.
What does the password do?+
It becomes the user password — anyone opening the PDF must enter it before the pages appear. Without it, the file can't be read, printed, or copied.
What is the owner password for?+
The owner password is optional and separate. It also opens the file and controls permissions (printing, copying, editing). If you don't set one, the user password is used for both.
Can I recover a forgotten password?+
No. This tool does not store your password anywhere and cannot recover it. Keep it safe — if you lose it, the protected file is unreadable.
Does it reduce the quality of the original content?+
No. Only the encryption layer is added — text, images, vectors and links all carry over without re-rendering or recompression. The output is identical to the original apart from the encryption.
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