Password Protect PDF — Free, No Upload
Encrypt documents locally with a password. Zero data leaves your device.
Drag & drop a PDF here
Files never leave your device.
Password-protect a PDF without emailing it to a stranger first
There is a particular absurdity in using an upload-based service to encrypt a confidential document: to protect the file from third parties, you first send it to one. This tool applies password encryption in your browser, so the unprotected original is never transmitted. It is worth understanding what PDF passwords actually do, because the format offers two quite different kinds and people routinely apply the weaker one believing it is the stronger.
How This Local-First Tool Works
- A user password — sometimes called an open password — is real encryption. Without it the file cannot be decrypted and the contents are genuinely inaccessible. This is the one worth using.
- An owner or permissions password is a different mechanism: it marks the file as "do not print" or "do not copy" and relies on the reader to honour that. Plenty of readers do not. Treat permissions as a courtesy, never as protection.
- The strength of the encryption is bounded by the strength of the password. A short, guessable password on an AES-encrypted PDF falls to an offline brute-force attempt quickly, because the attacker has the file and unlimited attempts.
- Send the password through a different channel from the document. A protected PDF and its password in the same email thread is functionally an unprotected PDF, and this is the most common mistake made with encrypted attachments.
Frequently Asked Questions
- What is the difference between a user password and an owner password?
- A user password encrypts the file — without it the content cannot be read at all. An owner password only sets permission flags such as no-printing or no-copying, which the PDF reader is trusted to enforce and many simply ignore. If you want the document actually protected, set a user password.
- Can the password be removed or recovered?
- Not by us, and not by anyone without the password — that is what encryption means. Store it somewhere you will not lose it, because a protected PDF with a forgotten password is unrecoverable for practical purposes.
- Is this secure enough for a client contract or an ID document?
- The encryption is standard PDF encryption and is appropriate for ordinary confidential business documents, provided you choose a strong password and transmit it separately. For highly sensitive material, encryption at rest in a managed system is a better fit than a password-protected email attachment.
- Does protecting a PDF stop someone screenshotting it?
- No, and no tool can. Once a recipient can read a document they can photograph the screen. Encryption controls who can open the file, not what a legitimate reader does with what they see.
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