How to protect a PDF with a password

  1. 1

    Upload your PDF

    Upload the PDF you want to protect.

  2. 2

    Set a password

    Enter the password you want to use. Keep it safe — if you lose it, no one can open the file.

  3. 3

    Download the protected PDF

    Click Protect PDF. Download the password-protected file.

About PDF password protection

Password-protecting a PDF prevents unauthorised access to sensitive documents. Once protected, the PDF requires the password to be entered before it can be opened in any PDF reader. DocumentFlipper applies AES-256 encryption — the same standard used by financial institutions and governments — to lock your document.

The tool supports two levels of protection: a user password that must be entered to open the document, and an owner password that controls permissions such as printing and editing. You can apply both for maximum control, or just a user password for a simple open-to-read restriction.

Your file is processed on our server over a secure HTTPS connection and deleted within two hours. The password is never stored or logged.

Frequently asked questions

What encryption standard does DocumentFlipper use?
DocumentFlipper applies AES-256 encryption, which is a military-grade standard used by financial institutions and governments.
What happens if I forget the password?
There is no recovery. If the password is lost, the file cannot be opened. Store your password somewhere safe.
Can I set printing or editing restrictions too?
Yes. You can set an owner password to restrict permissions like printing, copying text, and editing.
Will the password work in all PDF readers?
Yes. The encrypted PDF opens normally in Adobe Acrobat, Preview, and all standard PDF readers when the correct password is entered.
How long are my files stored?
Your uploaded PDF and the protected output are automatically deleted from our servers within two hours. Passwords are never stored.