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PDF Lock

Password-protect and encrypt your PDF files to prevent unauthorized access.

Drag & drop a PDF file here

or click to browse

or import from

How to Use PDF Lock

1

Upload your PDF

Select or drag and drop the PDF file you want to protect. The file stays on your device and is never uploaded to any server.

2

Set a password

Enter a strong password that will be required to open the PDF. Choose different user and owner passwords for granular access control.

3

Encrypt and download

Click lock to encrypt your PDF with AES encryption. Download the password-protected file instantly — it cannot be opened without the correct password.

About PDF Lock

PDF lock tool online — password-protect and encrypt PDF files instantly for free. Add strong AES encryption with user and owner passwords to prevent unauthorized access to your confidential documents. Set a password required to open the PDF and restrict editing, printing, and copying permissions. Perfect for protecting contracts, financial reports, medical records, legal documents, and sensitive business files. All encryption happens entirely in your browser using pdf-lib — your files are never uploaded to any server. No signup, no watermarks added.

Key Features

  • Password-protect PDF files with industry-standard AES encryption to prevent unauthorized access
  • Set both user password (to open) and owner password (to restrict editing and printing)
  • Client-side encryption ensures your PDF files never leave your device or get uploaded to any server
  • Download the fully encrypted and password-protected PDF file instantly after processing
  • Protect confidential documents, contracts, financial reports, and sensitive business files
  • 100% free PDF encryption — no signup, no watermarks, no file size restrictions

Frequently Asked Questions

How to password protect a PDF file online?▾
Upload your PDF, set a strong password, and click lock. The tool encrypts your file with AES encryption and downloads a password-protected copy. No signup required.
How to encrypt a PDF with a password for free?▾
Use our free PDF lock tool to add password protection. Upload the PDF, set your desired password, and download the encrypted file. All processing happens in your browser.
How to add a password to a PDF without Adobe Acrobat?▾
Our browser-based PDF lock tool works without any software installation. Upload your PDF, set a password, and download the protected file — no Adobe Acrobat needed.
How to protect a PDF from editing and printing?▾
Set an owner password to restrict editing, printing, and copying permissions. The user password controls who can open the document.
How to lock a confidential PDF document?▾
Upload the confidential PDF, set a strong password with mixed characters, and encrypt. The resulting file requires the password to open, keeping your information secure.
How to password protect a PDF on Mac or Windows?▾
Our tool works on any operating system through the browser. Upload your PDF on Mac, Windows, Linux, or mobile and get a password-protected file instantly.
How secure is the PDF encryption?▾
The tool uses standard PDF encryption with AES algorithm. Choose a strong password (12+ characters with mixed case, numbers, symbols) for maximum security.
How to remove the password from a locked PDF later?▾
Use our PDF Unlock tool and enter the correct password. The tool removes the encryption and downloads an unprotected copy of the PDF.