Protect PDF - Encrypt PDF & Add Password
Encrypt PDF documents with user passwords and custom security permissions.
Processed 100% locally in your browser. Passwords and files are never sent to a server.
About Protect PDF - Encrypt PDF & Add Password
Applies AES-128 encryption and user passwords to protect PDF files from unauthorized viewing, printing, or copying.
What Can You Use This Tool For?
Students, legal professionals, administrative teams, and business owners use Protect PDF with Password to quickly manage, convert, and optimize sensitive PDF contracts, assignments, and reports with guaranteed local browser privacy.
How to Encrypt PDF with Password
1. Select your PDF document.
2. Enter a strong password and confirm it.
3. Click "Encrypt PDF" to apply 128-bit AES encryption.
4. Download your password-protected PDF file.
Usage Examples
Password Protecting Confidential PDF
Input: Financial_Audit.pdf Password: "Secur3#PassWord2026" Result: Financial_Audit_Protected.pdf (Requires password to view)
Frequently Asked Questions
Are my PDF documents uploaded to a remote server?
No. Unlike traditional PDF conversion sites, Numvax processes PDF documents entirely inside your web browser using WebAssembly and client-side JavaScript. Your confidential files never leave your device.
What is the maximum PDF file size supported?
Because processing occurs in your local browser memory, you can manipulate large multi-page PDF documents smoothly without server upload timeout errors.
Will the formatting and fonts of my PDF be preserved?
Yes, the tool utilizes precision document rendering engines to maintain original text layout, font structures, vector graphics, and embedded images.
Can I process password-protected PDF files?
If a PDF requires a password, unlock it using our Unlock PDF tool first before merging, editing, or splitting.
What encryption level is applied?
Applies standard 128-bit AES encryption compatible with Adobe Acrobat and standard PDF viewers.
Related PDF Utilities
Explore complementary tools and calculators