Lock PDF

Add password protection to secure your PDF files

Browser Limitation Notice

PDF password protection requires server-side encryption libraries that cannot run in web browsers due to security restrictions. This tool would need a backend server to encrypt PDFs with passwords. For now, please use desktop PDF tools like Adobe Acrobat, PDFtk, or online services that support PDF encryption.

Select PDF File Password protection not available in browser environment

Password

Confirm Password

Recommended Alternatives

Desktop Software: Adobe Acrobat, PDFtk, PDF24 Tools
Command Line: QPDF, PDFtk Server, GhostScript
Online Services: Smallpdf, ILovePDF, Sejda (require server upload)
Programming: PyPDF2 (Python), iText (Java), pdflib (PHP server-side)

How to Use Lock PDF

Upload PDF

Choose the PDF file you want to protect with a password.

Set Password

Enter a strong password to encrypt and secure your PDF.

Apply Protection

Click Lock to add password protection to your document.

Download Secure PDF

Save your password-protected PDF file.

About Lock PDF

The Lock PDF Tool provides information about PDF password protection and encryption. While browser-based PDF libraries have limitations with password encryption, this guide explains PDF security options and best practices for protecting your documents.

Understanding PDF password protection:

User Password - Restricts who can open and view the PDF document
Owner Password - Controls permissions like printing, editing, and copying
Permission Settings - Fine-grained control over document interactions
Encryption Levels - Various encryption strengths from 40-bit to 256-bit AES
Professional Tools - Desktop software like Adobe Acrobat for full encryption
Server-Side Solutions - Advanced encryption requires server processing

Browser Limitation: Modern browser-based PDF libraries like pdf-lib cannot add password encryption due to complexity of encryption algorithms. For password-protected PDFs, we recommend professional desktop applications like Adobe Acrobat Pro, PDFtk, or qpdf command-line tools that implement full PDF encryption standards.