Lock PDF
Password-protect and encrypt your PDF files online for free. Add open and permissions passwords, restrict printing, copying, and editing. Fast, secure, and 100% browser-based.
Lock PDF With Password — Protect Your Documents Online
Sending a contract, a salary slip, or an Aadhaar copy over email without protection is like mailing a postcard — anyone who intercepts it can read everything. Adding a password to the PDF means only the person who has the password can open the file. It is the simplest form of document security and one that every bank, employer, and government portal already uses.
Our Lock PDF tool adds password encryption to any PDF in seconds. Choose an open password that the recipient must type before the file opens, and optionally restrict printing, editing and copying for anyone who opens it. The file is encrypted with 256-bit AES. No watermark and no cost, and your first 2 tasks a day need no account.
How to Password-Protect a PDF
There are two kinds of PDF passwords. An open password prevents anyone from viewing the document without typing it. A permissions password lets the file open but blocks printing, editing, or copying. You can use both at the same time.
1. Upload Your PDF
Drag a file from your device, Google Drive, or Dropbox. Any standard PDF is accepted, including ones that are already partially locked.
2. Set Your Password
Type a strong password. Optionally set separate permissions to allow viewing but restrict printing, copying, or editing.
3. Encrypt the File
The engine encrypts the PDF’s text, images and document details with 256-bit AES. Without the correct password, nobody can open it to read them.
4. Download the Locked PDF
Save the encrypted file and share it securely. The password you entered is never stored — only you and the recipient know it.
Why Protect Your PDF With a Password
Email is not encrypted end-to-end by default. Cloud links can be forwarded. USB drives can be lost. A password on the PDF itself is the one layer of protection that travels with the file no matter where it goes.
AES 256-Bit Encryption
The same encryption standard used by banks and governments. Breaking it by brute force would take billions of years with current hardware.
Open Password + Permissions
Require a password to open the file and separately restrict printing, editing, or copying. Use one or both layers depending on your needs.
Content Stays Untouched
The pages, text, images, and metadata inside the PDF are not altered. Only an encryption wrapper is added around the existing content.
Instant Encryption
Encryption runs in your browser, so most PDFs (up to 50 MB) are locked in seconds, with no upload and no queue.
Any Device, Any Browser
Lock a PDF from Windows, macOS, Android, iPhone, or Chromebook. No desktop software to install.
Zero Knowledge
We never see, store, or log the password you enter. If you forget it, we cannot recover it — that is the point of real encryption.