Password protect PDF
Encrypt a PDF with AES-256 so only people with the password can open it.
100% Browser-Based — Files Never Leave Your Device
About Protect PDF
Uploading a confidential document to a website just to protect it defeats the purpose. Here the encryption happens on your own device, using AES-256, the strongest algorithm in the PDF standard. Optionally restrict copying and editing for recipients.
How to protect PDF
- Select a PDF.
- Enter and confirm a password (optionally restrict copying and editing).
- Click "Protect PDF" and download the encrypted file.
Frequently asked questions
Is it safe to encrypt confidential PDFs here? Are my files uploaded?
Nothing is uploaded. PDFToolsFast runs entirely in your browser using JavaScript and Web Workers, so your files stay on your device. You can even disconnect from the internet after the page loads and the tool keeps working.
How strong is the encryption?
AES-256 (PDF 2.0, revision 6). It is supported by Adobe Acrobat, Chrome, Edge, Firefox, macOS Preview and most modern PDF readers.
What if I forget the password?
We never see or store it, so it can’t be recovered. Keep the original unprotected file or store the password safely.
What does "restrict copying and editing" do?
Recipients can open and print the PDF with the password, but compliant readers block copying text and editing. These restrictions depend on the reader honouring them.
Is it really free? Are there limits or watermarks?
Yes, it is free with no sign-up, no daily task limit and no watermark. Because your own device does the work, we have no per-file server costs to pass on.