Protect PDFs without uploading them
Add password protection to PDF files on your Windows device. PDF LockSmith encrypts documents locally — nothing leaves your machine.
How it works
Drop a PDF into PDF LockSmith, set a password, and the app creates an encrypted copy with AES-128 encryption. Pro users can upgrade to AES-256 and set granular permissions for printing, copying, and editing.
Your original file is never modified. The protected copy saves automatically next to the original or in your chosen output folder.
Why protect PDFs locally
Privacy by design — files never leave your device
No account needed — download and start immediately
Original untouched — protected copy is saved separately
Built-in password generator — create strong passwords instantly
Free vs Pro
The free tier includes password protection, removal, drag-and-drop, and auto-save. Pro adds owner passwords with granular permissions (printing, copying, editing restrictions), AES-256 encryption, metadata removal, and a searchable Password Vault. One-time purchase, no subscription.
Frequently asked questions
How does PDF LockSmith protect my files?
PDF LockSmith adds AES-128 password encryption (AES-256 in Pro) to your PDF files. You drag a file in, set a password, and the protected copy is saved automatically. The original remains untouched.
Are my PDFs uploaded during protection?
No. PDF LockSmith processes every file locally on your Windows device using a bundled copy of QPDF. Nothing is uploaded, transmitted, or stored externally.
What is the difference between Free and Pro?
Free gives you password protection, removal, drag-and-drop, auto-save, and a password generator. Pro adds owner passwords with granular permissions, AES-256 encryption, metadata stripping, and a searchable Password Vault.
Is there a subscription?
No. PDF LockSmith Free is free indefinitely. Pro is a one-time purchase — pay once, own forever. No recurring charges.