Edit PDF
PDF Security · AES-256

Password-Protect
Your PDF

Encrypt supported PDFs with AES-256 for readers that support standard encrypted PDF files.

Drop your PDF here

Drag & drop or click to browse
Up to 100 MB · Stays private

100% IN-BROWSER · ZERO UPLOAD · ZERO STORAGE

AES-256

The tool configures QPDF to create an AES-256 encrypted PDF for compatible readers.

Instant download

Click Lock PDF and your encrypted file downloads automatically — no extra step.

Universal

Opens in Adobe Acrobat, macOS Preview, Chrome, Edge, Firefox — any modern reader.

Before you start

Verified facts

Check access, supported files, limits, and processing before choosing a document.

Free

The core task does not require an account.

A PDF password lock applies standard PDF encryption so compatible readers request an open password before displaying the document. This tool configures QPDF to create an AES-256 encrypted PDF.

Price
Free — no account needed
Account
Not required
Processing
Processed locally in your browser via WebAssembly
Formats
PDF
File limit
No fixed application limit; practical capacity depends on browser memory and device performance
Browser support
Chrome, Firefox, Safari, Edge
Clear, practical guidance

What is a PDF password lock?

PDF Password Lock is a browser-based tool that lets you encrypt your PDF with AES-256 password protection. Choose PDF, use the controls above to configure the result, then download or use the resulting PDF. The core workflow runs locally in your browser without an application document-processing request. See formats, limits, and processing.

A PDF password lock applies standard PDF encryption so compatible readers request the open password before displaying the document. EditPDF AI applies AES-256 encryption.

You can also set PDF permission flags for printing, copying, or editing. Reader applications may choose how to enforce those flags. Encryption runs locally in your browser.

Practical examples

Common ways people use this tool in real documents and day-to-day workflows.

HR & payroll teams

Password-protect payslips, salary letters, and personal employee records before emailing them to individuals.

Legal & financial professionals

Lock contracts, settlement documents, and financial reports so only the intended recipient can access the content.

Educators

Protect exam papers and answer sheets with a password that is shared only after the assessment window closes.

Individuals

Secure personal documents — tax returns, ID scans, medical records — stored in cloud services or shared via messaging apps.

At a glance

Focused workflow

Encrypt your PDF with AES-256 password protection.

Supported workflow

Accepts PDF and produces PDF. Practical capacity depends on file size, browser memory, and device performance

Access and processing

Core tool with browser-based document processing.

Three simple steps

How it works

  1. 1

    Choose your PDF

    Select the PDF you want to protect. It is read locally in your browser.

  2. 2

    Set a password

    Enter an open password (required to view) and optionally a permissions password (controls printing and editing rights).

  3. 3

    Download the protected file

    Click Protect PDF. Encryption runs locally in your browser and downloads a protected file for compatible PDF readers.

Know before you upload

Formats, limits & privacy

Confirm that your file is supported and understand how this tool handles document data.

Input formats
PDF
Output formats
PDF
File limit
Practical capacity depends on file size, browser memory, and device performance
Privacy & security

Encryption runs locally in your browser without an application document-processing request.

Optional comparison

PDF Password Lock vs. doing it manually

Open this comparison if you are deciding between the browser workflow and a manual process.

Compare the workflows
Doing it manually

Trust that email or file-sharing permissions alone keep a sensitive PDF private.

With PDF Password Lock

Apply AES-256 encryption so a password is required before the document opens at all.

Doing it manually

Rely on a paid desktop suite to set PDF permissions and encryption.

With PDF Password Lock

Set an open password and permission flags for printing, copying, or editing, entirely in the browser.

Doing it manually

Hope every recipient handles the file responsibly once it's sent.

With PDF Password Lock

Even if the file is forwarded, it can't be opened without the password.

Quick answers

Frequently asked questions

What encryption does the PDF password use?
The tool creates an AES-256 encrypted PDF.
Can I set different passwords for viewing and editing?
Yes. The "open" password is required to open the file. The "permissions" password controls whether the viewer can print or copy text, even after opening.
Can I remove the password from a PDF I own?
If you know the password, yes — open the protected PDF in our tool and use the Remove Password option.
Does password protection prevent copying text?
The tool can set a PDF permission flag that requests copying restrictions. Reader applications may differ in how they enforce permissions.
Is my PDF or password sent to a server when locking?
AES-256 encryption runs locally in your browser via WebAssembly. Neither your document nor your password is ever sent to a remote server.
Can I set a permissions password without an open password?
Yes. You can set only a permissions password to restrict printing or editing while leaving the file openable without a password, or set both together.
Learn more

Guides & real-world workflows

Step-by-step guides

How to password protect a PDFPassword protect vs. redact a PDF: which do you need?

Common use cases

Password-Protect a PDF Before Sharing Personal Data
Used in workflows for: Small Businesses · Accountants · Healthcare Teams
All role workflows →
Core PDF tool

Ready to use PDF Password Lock?

Encrypt your PDF with AES-256 password protection Return to the tool above to choose your file, or browse the complete PDF toolkit for another task.

Use PDF Password LockBrowse all PDF tools