Encrypt PDF
Password protect a PDF free, entirely in your browser — set a password to open the file, optionally an owner password and print, copy or edit limits, and it is encrypted with AES-256.
- Add
- Adjust
- Make
- Keep
How to use this tool
- Open Encrypt PDF and drop in the PDF you want to protect.
- Set a strong user password (anyone opening the file will need it), repeat it to catch typos, and optionally add a separate owner password to control permission changes.
- Watch the password-strength indicator, then choose which actions (printing, copying, modifying content, filling forms) should stay allowed.
- Read the recovery warning, tick the confirmation, run the tool and download the protected copy. Encryption happens on your device with AES-256.
About this tool
Password protect a PDF free, entirely in your browser — set a password to open the file, optionally an owner password and print, copy or edit limits, and it is encrypted with AES-256. Nothing is uploaded; a forgotten password cannot be recovered by anyone, and the permission limits depend on the viewer.
Privacy & limitations
A lost user or owner password cannot be recovered by this app or by anyone else. Encryption is irreversible by design, so keep the password somewhere safe. Permission switches (printing, copying, editing) are advisory: they rely on the PDF viewer honouring them, and some tools ignore them. Only the user password truly stops people opening the file. If you leave the owner password blank, a random one is generated and discarded. This tool encrypts a new file and cannot re-encrypt a PDF that is already password-protected; remove the existing password first. Very large files can run out of memory on a phone, and the original, unprotected file you started with is not deleted.
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Frequently asked questions
How do I password protect a PDF without uploading it?
Add the PDF, choose a user password and repeat it, pick which actions stay allowed, tick the recovery warning, and run. The file is encrypted inside your browser and downloaded as a new copy, so the original and the password never leave your device.
What kind of encryption does Encrypt PDF use?
AES-256, the strongest standard PDF encryption (PDF 2.0, security handler revision 6), written by qpdf compiled to WebAssembly. Current versions of Acrobat Reader, Chrome and Preview open it with the password; very old PDF readers may not support AES-256.
Can a forgotten PDF password be recovered?
No. Nothing is stored and there is no reset or back door, so neither this app nor anyone else can open the file without the password. Save the password in a password manager and keep the unprotected original somewhere safe until you have tested the new copy.
Do the print and copy options really stop people?
Only partly. Printing, copying and editing limits are flags that well-behaved viewers respect, but some software ignores them or removes them. Only the user password reliably stops someone opening the file, so rely on that when the content is sensitive.