Lock PDF

Password-protect your PDF files for free directly in your browser. Set a strong password to secure sensitive documents. No uploads, no account needed.

Drag & Drop PDF File Here

or

No file selected.
Security Options

Setting a Permissions Password enables the options below.

User Permissions (If Permissions Password is set):
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PDF Security

Lock PDF

Secure your PDF document with strong password encryption to control opening, editing, printing, and copying permissions.

Strong Encryption
STEP 01

Upload PDF

Drag and drop your PDF or click to browse files from your computer.

STEP 02

Set Password

Enter a secure user password to protect against unauthorized open requests.

STEP 03

Set Permissions

Select optional access restriction settings (printing, copying, form edits).

STEP 04

Lock & Download

Click to apply security settings and download your secure PDF file instantly.

Your Privacy Matters

All processing stays in your browser

No Server Uploads

Files never leave your device

Auto-Cleared

Data removed when you close

Capabilities

Document Encryption Features

File cryptography

Dual Password Layers

Configure distinct open password criteria or separate owner permission bypass hashes.

Fine-Tuned Restrictions

Limit capability options including content extracting, form edits, or paper printing.

High-Grade AES Security

Applies industry standard AES-128 or AES-256 cryptographic containers to encapsulate objects.

Fast Offline Cryptography

Encryption routines run client-side using JavaScript, providing instant downloads.

100% Client-Side Privacy

Your password keys, encryption calculations, and documents stay completely on your computer. We never store or transmit your security codes or files over the network.

Support

Common Questions Answered

Quick help
Q1 What is the difference between User and Owner passwords?
A User password is required to open and read the file, while an Owner password controls permission configurations, letting you restrict copying, printing, or form filling.
Q2 What encryption standards does the Lock tool use?
We apply standard 128-bit and 256-bit AES encryption schemes, which are widely accepted and compatible with all modern PDF readers (like Adobe Acrobat, Chrome, and system viewers).
Q3 Can someone bypass or crack the locked PDF?
No. Standard AES encryption algorithms secure files cryptographically. Without the correct password string, standard readers cannot parse or display the document parameters.
Q4 What happens if I forget my password?
Because we run 100% client-side and value privacy, we do not store, track, or index passwords. We are unable to recover or reset forgotten PDF passwords.
Q5 Are my private files or password codes sent to your server?
No. All cryptographic algorithms run inside your local browser memory sandbox. Your security passwords and files never leave your machine.