Free Protect PDF with Password (AES-256 Encryption) Online
Encrypt sensitive financial, medical, and legal PDF documents with military-grade 128-bit or 256-bit AES password encryption. — 100% free online utility, zero sign-up, zero paywalls, and private client-side processing.
How It Works
Select Document
Drop your PDF file into the encryption workspace.
Set Secure Password
Enter your custom document open password.
Configure Permissions
Optionally disable printing, editing, and text copying.
Download Locked PDF
Save the encrypted PDF file safely.
Frequently Asked Questions
Related PDF & Documents Calculators & Utilities
Interlinked precision tools in the PDF & Documents collection.
Unlock PDF (Remove Password & Print Restrictions)
Remove owner security restrictions and decrypt passwords from your authorized PDF files for unrestricted printing and copying.
Add Watermark to PDF (Confidential, Draft & Custom Logo)
Stamp custom text or transparent image watermarks (e.g. 'CONFIDENTIAL', 'SAMPLE', company logo) across all PDF pages.
Flatten PDF Forms (Lock Form Fields & Annotations)
Flatten interactive AcroForm text fields, checkboxes, and digital signatures into permanent, un-editable background text.
Merge PDF (Combine Multiple PDF Files)
Combine multiple PDF documents into a single organized file with drag-and-drop page reordering 100% in your browser.
Split PDF (Extract Pages & Separate Files)
Split a multi-page PDF into individual single-page files or extract specific page ranges (e.g. 1-3, 5, 8-12) with instant download.
Compress PDF (Reduce PDF File Size)
Compress PDF document size to 100KB, 200KB, or 500KB for government job portals, university applications, and email limits.