Password protect a PDF using this free, browser-based tool that encrypts your document so only recipients with the correct password can open it. Set a strong password, apply it to your file, and download the protected PDF instantly. No signup is required, and the encryption process runs entirely in your browser without transmitting your file to any server.
PDF Password Protect is a free browser-based tool that adds password protection to a PDF file. Users upload a PDF, set an owner password, optionally set a user password for opening the document, and download an encrypted PDF. Password-protecting a PDF prevents unauthorised users from opening the file or, depending on the settings, from editing, printing, or copying its content. This is useful for sharing sensitive documents such as financial reports, legal agreements, HR records, and personal identification documents over email or through file sharing services where access control matters. The tool uses pdf-lib to apply AES-based encryption directly in the browser, so the original file is never sent to a server. The protected PDF is compatible with all standard PDF viewers that support encryption. No account or installation is required.
PDF password protection works at two levels. The user password restricts who can open the document: anyone who does not know the password cannot read the file at all. The owner password restricts what actions are permitted once the document is open: it controls whether the content can be copied, printed, or modified. Setting both passwords provides the most complete protection. Setting only an owner password allows anyone to open the file but restricts what they can do with the content. A common use case is distributing a report that recipients may read and print but should not be able to copy and redistribute as their own. PDF encryption uses AES-128 or AES-256 depending on the compatibility level selected, which is the same encryption standard used for sensitive data in many industries. However, password strength matters: a short or obvious password can be brute-forced with freely available tools. Using a long random password stored in a password manager provides meaningful security. For workflows where a document needs both watermarking and password protection, applying the watermark first using PDF Watermark and then password-protecting the result with this tool creates a document that is visually marked and access-controlled. The tool processes files entirely in the browser with no server upload, which is particularly important when handling documents that are sensitive enough to require password protection.