Send a confidential document
Encrypt a contract, payslip or medical report with AES-256 before it goes out by email or messenger.
Files never leave this device
Local encryption
Password-protect a PDF without it ever leaving your device.
Encrypt with AES-256 directly in your browser. The file and the password stay on this device — and if the password is lost, this tool cannot get the document back.
Reading files…
What it solves
Real encryption, done where the secret is safe.
This tool encrypts your PDF with modern AES-256 using qpdf compiled to WebAssembly, so the work happens inside your browser. That matters more here than anywhere: a password typed into a website that uploads your file is a password shared with a server. Here, both the document and the password stay on this device. You type the password twice (at least 6 characters) to rule out typos, then export the protected copy.
Keep the password safe: encryption this real cuts both ways, and a lost password means the tool cannot recover the document.
Common uses
Work on your own locked file
Make an unlocked working copy of a PDF whose password you know, so you can merge, edit or print it without retyping the password.
Rescue a broken file
Rebuild a truncated download or a scan with a broken structure, and see exactly how many pages survived.
Quick guide
Protect, unlock or repair — always on this device.
- 01Add the PDF. It is read on this device only; nothing is uploaded anywhere.
- 02Set what the task needs: a new password to protect, the file's known password to unlock — a repair needs no input at all.
- 03Run the action. qpdf, compiled to WebAssembly, does the work inside your browser.
- 04Read the honest result report and download the new copy. The original file on your device is never touched.
Limits worth knowing
Honest about what it cannot do.
- 01
Unlock only removes protection when you provide the correct password. It cannot crack, bypass or recover a password you do not know.
- 02
If you protect a file and later lose the password, this tool cannot restore access. Store the password somewhere safe.
- 03
Some damaged files are beyond repair. When that happens, the tool says so instead of exporting a garbled document.
- 04
Very large files are limited by the memory this device can spend on a browser tab.
Frequently asked questions
Protecting a PDF — FAQ.
01Do my file and password leave this device?
No. qpdf runs as WebAssembly inside your browser, so the file and any password you type are processed on this device and sent to no server.
02Can it remove a password I don't know?
No. Unlock produces an unprotected copy only when you enter the file's correct password. It does not crack, bypass or recover unknown or forgotten passwords.
03How strong is the protection?
Protect encrypts with modern AES-256. The practical strength depends on the password you choose — and this tool cannot recover a lost one.
04What happens when a file cannot be repaired?
The repair reports exactly how many pages could be rebuilt. If the structure is too far gone, the tool declares the file unrepairable rather than producing garbage — and your original stays untouched either way.
Related tools
Keep working on the document.
01 / PDF
All PDF toolsUnlock PDF with the Known Password
Use the password you already know to decrypt a PDF locally and create an unlocked working copy.
Open tool02 / PDFRedact PDF Safely
Mark sensitive areas, rebuild the visible pages, remove the original searchable layer and verify the exported copy before sharing.
Open tool03 / PDFRemove PDF Metadata
See the document title, author, subject, keywords, creator and producer, then create a clean copy with those fields removed.
Open toolShare this tool
Referencing this tool on a website?
Copy an attribution link. It is optional and does not change free access.