Set a password on your PDF to prevent unauthorized access. Encryption runs in your browser, nothing is sent to a server.
PDF password protection encrypts a PDF with a password of your choice using AES-256, the level defined by the PDF 1.7 extended specification and read by Adobe Acrobat, macOS Preview and most modern viewers.
This matters for sensitive documents: salary slips, legal drafts, personal records. The password you choose is the only key, with no recovery mechanism by design, so store it in a password manager, a file encrypted here cannot be opened again without it.
No. Every operation runs inside your browser tab using JavaScript and WebAssembly. Your file is read into memory on your own device, processed there, and the result is offered as a local download. Nothing is transmitted to Sunasty or any third party. You can verify it yourself: open your browser DevTools, go to the Network tab, and watch, no request carries your file.
The tool applies AES-256 encryption, which is the level used by the PDF 1.7 extended specification and is recognised by Adobe Acrobat, Preview on macOS, and most modern PDF readers. The password you choose is the only key, Sunasty does not store or know it.
The tool encrypts with a single user password that restricts opening the document. If you need fine-grained permission controls (print-only, copy-restricted, and so on) with a separate owner password, use a local desktop application that supports the full PDF permission model.
There is no recovery mechanism, by design, only the password unlocks the file. Keep it in a password manager. If you lose the password to a file you encrypted here, the content is unrecoverable.
Yes, once the page has loaded. Because the processing happens on your device, you can disconnect from the network and the tool keeps working. This is the clearest proof that your data never leaves your machine.
It is completely free and requires no sign-up. There are no watermarks, no daily limits and no tracking cookies needed to use the tool.