Password Protect PDF Online Free
Password-protect your PDF with AES-128 encryption — free, in-browser.
Drop a PDF here or click to select
The file will be encrypted with AES-128 in your browser
Required to open the document
Controls editing permissions
⚠️ Important
Store your password safely. If you lose it, the PDF cannot be recovered. Your password is never sent to any server.
About Protect PDF
Encrypt any PDF with a user password so it cannot be opened without the correct credentials. Uses AES-128 encryption — the same standard used by professional PDF software. All encryption is performed entirely in your browser; no file is ever uploaded anywhere.
Use Cases
Protecting confidential documents before emailing, locking PDFs with sensitive financial or personal data, securing contracts before sharing with clients.
How It Works
Uses pdf-lib to re-save the PDF with AES-128 encryption applied. The encrypted file is downloaded directly to your device. The password you set is never transmitted to any server.
FAQs
What encryption standard is used?
AES-128, the same algorithm used by Adobe Acrobat and other professional PDF tools.
Can I remove the password later?
You can use a PDF password-removal tool if you know the correct password. Without the password, recovery is not possible.
Is my password stored anywhere?
No. The password is only used inside your browser to encrypt the file and is never sent to any server.