Password-protect a PDF so it cannot be opened without the password: type a password of at least 6 characters twice, and download the locked copy. Use it before emailing a payslip, a tax return, a signed contract or a scan of your passport. The file is encrypted, not re-rendered, so the pages are exactly the same once it is unlocked. Encryption happens in your browser, and neither the PDF nor the password is sent anywhere. Several PDFs can be locked with the same password in one go and come back as a ZIP.
How it works
- Drop one PDF, or several to lock with the same password. A file that is already encrypted, or a PDF/A archive copy (that standard forbids encryption), is refused with a message.
- Type a password of at least 6 characters, then type it again to confirm. The button stays disabled until both match.
- Press Protect & download. For a single file, the result line names the exact cipher used, for example AES-128 (PDF 1.7, /V 4), and the size before and after.
Questions
- Is the PDF encrypted with AES-256?
- No, and the result line will not claim it. The cipher follows the version your file declares: PDF 1.6 and 1.7 get AES-128, PDF 1.4 and 1.5 get 128-bit RC4, and any other version gets 40-bit RC4, which is weak. The result line names the one used. Whatever the cipher, a long password matters more than a clever short one.
- Can I stop people printing or copying from my PDF?
- Not with this tool. It sets one password as both the open password and the owner password, and adds no print, copy or edit restrictions. The point is that nobody can open the file without the password; anyone you give the password to gets the whole document.
- Can I remove a PDF password or recover a forgotten one?
- No to both. There is no unlock mode, and an already-encrypted PDF is refused rather than locked twice. The password is only used in your browser and is never sent anywhere, so there is no reset and no copy to recover: keep it in a password manager. To change a password, export an unlocked copy from an app that knows the current one, then protect that.
- Does my file get uploaded?
- No. The models and all processing run inside your browser on your own device. You can verify this yourself: open your browser’s DevTools, watch the Network tab, and process a file: there are no uploads. After the first visit most tools also work fully offline.
- Is merge/split lossless?
- Yes. Merging, splitting, reordering and rotating copy pages intact: text stays selectable, links keep working, quality is untouched. Only the compress pages re-encode content, and they say so.
- How strong is the password protection?
- Without the password the file cannot be opened. The cipher follows the PDF’s own version: AES-128 for PDF 1.6 and 1.7, and the older RC4 cipher for other versions. Choose a real password: the encryption is only as strong as it.
- Can it compress any PDF to 100 KB?
- No, and it will not pretend to. Image-heavy pages compress well; a born-digital text PDF may already be near its floor. The tool reports the size it achieved rather than silently overshooting.