Password protect a PDFwith AES-256 encryption
Lock a PDF with a password so only the people you share it with can open it.
- Free during beta
- No sign-up
- 25 MB per file
Guest session. Files automatically expire after 60 minutes.
In short
EnDocs AI encrypts a PDF with AES-256 and the password you choose, so the file cannot be opened without it. Printing, copying and annotating remain allowed once it is opened.
What it is
What is Protect PDF?
Password protection encrypts the contents of a PDF. Without the password, viewers show a prompt and the text, images and pages cannot be read.
It is the simplest way to send a contract, payslip or statement over email and know that a forwarded or lost copy is not readable on its own.
Try saying
“Protect this PDF with the password "Blue-Harbour-42".”
How to use it
Protect PDF in 3 steps
- 1
Upload your PDF
Drop your file in the box above or choose it from your device. No account is needed.
- 2
Set a password
Say "protect this with the password …". Choose something you can share separately and remember.
- 3
Download the result
Your encrypted PDF is ready. Download it, or keep working on it in the same workspace.
Behind the scenes
How your file is processed
AES-256 encryption
The file is encrypted with AES-256, a strong standard encryption used for sensitive documents.
Open password and owner password
The password you give is required to open the file. A separate owner password can be set; if you do not, the same password is used.
Permissions after opening
Once opened, the document can be printed, copied and annotated.
Already protected files
If the PDF is already locked, you are asked for its current password before it can be re-protected.
Your file stays yours
- Files are deleted automatically about 60 minutes after upload, when your guest session ends.
- Names, numbers, emails and addresses are swapped for placeholders before text reaches an AI model, then restored in the reply.
- No account is created. Your guest session is the only thing that identifies your files.
At a glance
Protect PDF facts
- Input
- One PDF
- Output
- One encrypted PDF
- Encryption
- AES-256
- File size
- Up to 25 MB per PDF
- Account
- Not needed, guest session
- Price
- Free during the beta
- Files kept for
- About 60 minutes, then deleted
Who uses it
When Protect PDF helps
Contracts and offers
Send agreements by email with the password shared another way.
Payslips and statements
Protect personal financial documents in transit.
Client deliverables
Release a report to the right person only.
Personal records
Lock scans of IDs, medical letters or tax papers before storing them.
Tips for better results
- Use a long phrase rather than a short word, and send it by a different channel than the file.
- Keep the password somewhere safe. A lost password cannot be recovered by us.
- Add a watermark first if you also want the pages marked, then protect the final file.
FAQ
Protect PDF: common questions
Upload the PDF, tell EnDocs AI the password to use, and download the encrypted PDF.
Keep going
Related PDF tools
Ready to use Protect PDF?Start with your file.
Upload a PDF and EnDocs AI will take it from there. You can also summarize it or ask it questions in the same workspace.
Free during the beta. Files are removed after 60 minutes.