FREE TOOL · ON YOUR DEVICE
Password protect a PDF for free
Create an encrypted copy that requires a password to open. qpdf performs AES-256 encryption in a local browser engine. Keep the password safe: Cocuyo does not save or recover it.
- Real AES-256
- Opening password
- 30 free uses
- Load the original
- Enter the password
- Encrypt and verify
HOW TO USE IT
Three steps.
Load the original
Choose an unencrypted PDF.
Enter the password
Use at least 8 characters. The password is not saved; make sure you can remember or retain it.
Encrypt and verify
Process, inspect the local preview and download the copy. Test opening it in your reader using the password.
NEXT STEP
Keep going with these tools
Protect PDF: common questions
Is the document really encrypted?
Yes. qpdf creates an AES-256 encrypted PDF with an opening password. Protection is not simulated using a watermark or a notice.
Can I recover a forgotten password?
Cocuyo does not store or recover passwords. Keep the original PDF and password. Up to 127 UTF-8 bytes are accepted; empty passwords, line breaks and null characters are rejected.
Does it prevent an authorised person from copying content?
After opening with the password, a reader can display the content. This tool requires an opening password; it does not promise to prevent screenshots or every later copy.
Is it free and where is the PDF processed?
You can load and process the PDF before signing up; to download it, we ask for a free account. That account comes with 30 welcome uses; after that, each use costs 1 credit. PDFs and passwords are processed on your device; only the session is checked and local Cocuyo engines are downloaded.
What are the limits?
PDFs up to 50 MB and 100 pages. Output is limited to 100 MB. You can cancel processing; device memory and speed may limit complex files.
What happens to signed or encrypted PDFs?
Always keep the original. PDFs with existing digital signatures and XFA forms are not modified. For an encrypted PDF, use Unlock PDF with a known password and permission to do so.
Are my PDFs uploaded to a server?
No. The tool runs inside your browser: documents are read and processed on your device and are not sent to Cocuyo or to any third party. The PDF libraries are served from our own site, with no external services. You can check it in your browser’s network tools: your file is not sent.
Is it really free?
Yes. You can try it before signing up; to download the result we ask for a free account, with no subscription. Your free account comes with 30 welcome uses; after that, each use costs 1 credit (top-ups from US$1), and they are unlimited with Basic or Pro. It never adds a watermark.
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WHEN YOU WANT TO CREATE
Make new images with AI.
Cocuyo’s Studio brings 30+ AI models for image, video and voice together. You see the credit cost before generating, and credits never expire.