Free PDF Password Protector - Encrypt Your PDF with a Password
Add password protection to your PDF file to restrict access. 128-bit or 256-bit AES encryption. Runs entirely in your browser — files never leave your device.
What is Protect PDF?
Guard your sensitive PDF documents with password encryption using our free browser-based PDF Protector. Set an owner password to control access and optionally a user password to restrict operations like printing, copying, or editing.
The tool uses pdf-lib to apply AES encryption (128-bit or 256-bit, your choice) to the document. Once protected, the PDF will prompt for a password whenever it is opened in any PDF viewer — Adobe Reader, Chrome, macOS Preview, or any other standard reader.
You can also set permission flags: prevent printing, prevent copy-pasting of text, prevent editing. This is useful for distributing documents where you want readers to view but not modify or copy the content.
All encryption happens client-side in your browser using pdf-lib's built-in encryption support. Your document's content is never transmitted to any server in its original unprotected form. This is essential when protecting confidential contracts, financial documents, or proprietary reports.
Powerful Features
Everything you need in one amazing tool
AES Encryption
Apply 128-bit or 256-bit AES password encryption — the same standard used by banks.
Owner & User Passwords
Set separate open and permissions passwords. Control who can open vs. who can modify.
Permission Flags
Restrict printing, copying, editing, and form-filling independently per document.
Universal Compatibility
Protected PDFs work in Adobe Reader, Chrome, Firefox, macOS Preview, and mobile viewers.
Client-Side Encryption
Your unprotected document never leaves your browser. Encryption is fully local.
Instant Protection
Password is applied and the protected PDF is ready to download in under a second.
How It Works
Get started in 4 easy steps
Upload Your PDF
Select or drop the PDF you want to password-protect.
Set Password
Enter your chosen password. Optionally set an owner password and permission flags.
Choose Encryption
Select 128-bit or 256-bit AES. Higher bit strength offers greater protection.
Download Protected PDF
Click Protect. pdf-lib encrypts and downloads your password-protected PDF instantly.
Why Choose Our Protect PDF?
Stand out from the competition
Strong Encryption
AES-256 encryption is industry-standard and effectively unbreakable with strong passwords.
No Server Access
Document content never leaves your browser. Privacy guaranteed by design.
Granular Permissions
Control exactly what operations are permitted beyond simply opening the file.
Works Everywhere
Protected PDFs open in all standard PDF viewers that support password-protected files.
Instant Encryption
AES encryption is applied in milliseconds in your browser. No delay regardless of file size.
Free & Private
No cloud service needed. Documents are encrypted locally and never uploaded anywhere.
Perfect For
See how others are using this tool
Confidential Reports
Password-protect financial or strategy reports before emailing to stakeholders.
Client Deliverables
Protect deliverables so only clients with the password can open them.
Exam Papers
Encrypt exam PDFs to prevent early access. Share the password separately.
Personal Documents
Protect scanned IDs, certificates, and personal records stored in cloud storage.
Intellectual Property
Password-protect proprietary design documents or tech specs before sharing with contractors.
Board Documents
Secure board meeting packs and financial disclosures before distributing to directors.
Frequently Asked Questions
Everything you need to know about Protect PDF
AES-256 is recommended for sensitive documents. AES-128 is compatible with a wider range of older PDF readers but is slightly less secure.
The user (open) password is required to open the file. The owner (permissions) password is required to change the permission settings or remove restrictions.
The PDF is encrypted at the file level. Anyone who opens it in a PDF viewer will be prompted for the password. It can be removed only with the correct password using our Unlock PDF tool.
No. Encryption is performed entirely in your browser using pdf-lib. Nothing is uploaded.
You need to unlock it first with the existing password, then apply a new password protection.
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