Tool
Lock PDF
Password protect any PDF in seconds. Set a password — anyone trying to open the file will need it.
Drop a PDF here, or click to browse
About PDF Password Protection
Locking a PDF adds 128-bit RC4 encryption to the file. When someone tries to open the document in any PDF reader — Adobe Acrobat, Preview, Chrome, or any other viewer — they will be prompted for the password before the contents are displayed.
This is useful for sending sensitive documents by email, sharing PDFs on shared drives, submitting forms that contain private information, or any situation where you want to control who can read the file.
The encryption runs entirely in your browser using the Web Crypto API. Your PDF is never uploaded to a server. Choose a strong password — the longer and more random it is, the harder it is to crack. Do not forget it: if you lose the password, the file cannot be opened.
Password strength matters. A short dictionary word can be cracked in seconds; a random 16-character string combining letters, numbers and symbols would take years. Use the Password Generator to create a strong one. After downloading the locked file, open it in your PDF reader to confirm the password works before sending to anyone.
Need to remove a password instead? Unlock PDF →
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