Protect PDF with a Password
Lock a PDF with a password before you email or share it. The file is encrypted with AES-256, the strongest standard PDF encryption, right here in your browser.
Runs in your browser
How to use
- Drop the PDF you want to protect.
- Type the password twice.
- Choose whether printing, copying and editing stay allowed.
- Click Protect PDF and download the encrypted file.
How it works
The tool runs qpdf, a widely used open-source PDF library, compiled to WebAssembly so it works inside your browser. It encrypts every page, image and font with AES-256 (the security handler introduced with PDF 2.0 and Acrobat X), which Adobe Reader, Preview, Chrome, Edge and Firefox all open.
The password you type is the only way to open the file. A second, random password is generated for the permissions, so the opening password alone cannot be used to change them. Permissions such as “no printing” are honoured by standard readers, but they are instructions to the reader rather than encryption: anyone who can open the file could still photograph or re-type it.
Nothing is uploaded: the PDF and the password stay on your device, and the password is not stored anywhere — if you forget it, the file cannot be recovered.
Examples
- Payslip or tax form by email
- Protect the PDF, send it, then give the password by phone or text message — never in the same email.
- Read-only report
- Allow printing but block copying and editing, so the text is not pasted elsewhere by mistake.
Common uses
- Emailing documents with personal data
- Sharing contracts or HR files
- Storing scans of IDs in shared folders
Privacy & security
This tool runs entirely in your browser. Your files and text are never uploaded to our servers — processing happens on your device and results are created locally. How each tool handles files
Frequently asked questions
How strong is the protection?
AES-256 with a good password is not practically breakable. The weak point is the password: use at least 12 characters, or a passphrase of four or five random words.
Is my password sent anywhere?
No. Encryption runs in your browser; neither the file nor the password leaves your device, and nothing is stored.
What if I forget the password?
The file cannot be opened. Keep your original unprotected copy, or store the password in a password manager.
Can I protect a PDF that is already protected?
Unlock it first with its current password, then protect it again with the new one.
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