Protect PDF
Add an opening password with AES-256 encryption, privately in your browser.
Your files never leave your devicePreparing local PDF tools…
How to use Protect PDF
Encrypt an unlocked PDF with AES-256 and an opening password. This protects access to the file; it does not stop an authorized reader from copying or photographing content.
- Choose an unlocked PDF of up to 20 MB.
- Enter and confirm a strong opening password. Save it separately.
- Protect, download, and test the opening password before sharing.
A practical example
Share a protected document and send its password using a different communication channel.
Before you share the result
- Use a unique password of at least eight characters; a longer passphrase is better.
- Forgotten passwords cannot be recovered by Omnikitz. Modern PDF readers are required.
- Existing certificate signatures can become invalid when a PDF is rewritten.
Useful things to know
Are my files private?
Yes. All document operations run locally in your browser. We don’t upload your files, and files are not saved between visits. Close or reload the page to clear the workspace.
What are the file limits?
PDF inputs: up to 20 MB and 1,000 pages; interactive editing/signing: up to 200 pages. Scanning: up to 20 photos, 30 MB per photo and 80 MB combined, downsampled to two megapixels per page. Mobile devices may need smaller files.
What should I expect from this tool?
Use a unique password of at least eight characters; a longer passphrase is better. Forgotten passwords cannot be recovered by Omnikitz. Modern PDF readers are required. Existing certificate signatures can become invalid when a PDF is rewritten.
Is Protect PDF free, and how is my privacy handled?
Yes. Protect PDF is free to use without registration. Tool inputs are processed in your browser rather than uploaded to our servers. Optional usage analytics follows your cookie preferences; it does not receive your files or tool inputs. Keep your browser updated and review results before sharing.