Encrypt PDF
Add a password and encryption to protect a PDF.
- 100% Private
- No Limits
- Works Offline
or drag and drop here
Add real AES-256 password protection to a PDF using qpdf — the same trusted engine many desktop and server tools rely on — compiled to run entirely in your browser.
How to Use Encrypt PDF
- 1
Upload your PDF
Click the upload area or drag in the document you want to protect.
- 2
Set a password
Type a password and confirm it.
- 3
Encrypt and download
Your password-protected PDF downloads immediately — nothing is uploaded first.
Why Choose PurePDF for Encrypt PDF
Nothing leaves your device
Encryption runs locally via qpdf compiled to WebAssembly — your document and password never touch a server.
Real AES-256 encryption
Uses qpdf's standard security handler, not a simplified or custom scheme.
One password, fully protected
The same password is required to open and to change permissions — simple to use and remember.
Common Use Cases for Encrypt PDF
Protect sensitive documents
Add a password before emailing contracts, financial statements, or personal records.
Secure an archive
Password-protect documents before storing them long-term.
Share safely
Send a protected file and share the password separately through a different channel.
Pro Tips for Encrypt PDF
- There's no way to recover a lost password — store it in a password manager.
- Share the password through a different channel than the file itself (e.g. a text message, not the same email).
- Use Remove Password later if you no longer need the protection.
Frequently Asked Questions About Encrypt PDF
Will my PDF file be uploaded to a server?
No — nothing is uploaded. This tool runs entirely in your browser via WebAssembly/JavaScript; your file never leaves your device.
Is there a file-size limit, a usage cap, or a hidden fee?
It's free and unlimited, with no watermark and no forced file-size cap — the only real limit is your own device's memory for very large files.
Do I need to create an account or sign up?
No — no account, email, or sign-up is required for any tool. Just start using it.
Can I use this on my phone (iPhone or Android)?
Yes — it works in any modern mobile browser, no app install needed.
What encryption standard is used to protect the PDF?
It uses genuine AES-256 encryption powered by qpdf to protect the document.
Can I recover the PDF if I forget the password?
No. There is no way to recover a lost password, so make sure to save it in a password manager.