Protect PDF at a glance
- Price
- Free
- Account
- Not needed
- Watermark
- None
- Privacy
- Files are processed inside your browser and are never uploaded.
- Works on
- Windows, Mac, Linux, Android and iPhone – in any modern browser
- Install
- Nothing to install
AES-256 encryptionThe same strong standard used by Adobe Acrobat and banks.
Optional restrictionsBlock printing, copying or editing even for people who can open the file.
Strong password helperA strength meter and a one-tap strong password suggestion. Your PDF and password never leave your device.
How to use Protect PDF
- Press Select PDF file.
- Type a password twice (and set restrictions if you like).
- Press Protect PDF and download the locked file.
Choosing a good password
- Use at least 8 characters, mixing letters, numbers and symbols.
- Do not use your name, phone number or date of birth.
- Send the password separately from the file, for example by phone or a different chat.
- Write it down: a lost password cannot be recovered – not even by us.
Which apps can open the protected PDF?
Every modern PDF reader – Adobe Acrobat Reader, Chrome, Edge, Safari, Firefox, Preview on Mac and phone PDF viewers – will ask for the password and open the file.
Choosing a strong password
- Use at least 10 characters with words, numbers and symbols – for example a short sentence like Blue-Tea-at-7pm!.
- Do not use your name, phone number, CNIC or date of birth.
- Send the password in a different way than the file – for example the file by email and the password by phone or SMS.
Good to know
- The PDF is encrypted with AES, the same strong standard used by Adobe Acrobat. Without the password it cannot be opened.
- We cannot recover a forgotten password – keep it somewhere safe.
- To remove the password later (when you know it), use Unlock PDF.
Frequently asked questions
Is Protect PDF free?
Yes, free with no sign-up and no watermark.
How strong is the protection?
Your PDF is encrypted with AES-256 using the PDF 2.0 security handler (revision 6), the same standard used by Adobe Acrobat X and later. With a good password it cannot be opened without that password.
How do I choose a good password?
Use at least 10 characters with a mix of words, numbers and symbols, and avoid names or birthdays. Send the password to the receiver separately from the file, for example by SMS.
Can you see my password?
No. Encryption happens in your browser. Neither the file nor the password is sent anywhere.
I forgot my password. Can you help?
No. Strong encryption means a forgotten password cannot be recovered, so keep an unprotected copy of the original file in a safe place.
Will it open on phones?
Yes. Modern PDF readers on Android, iPhone, Windows and Mac open AES-256 PDFs after you type the password.
Guides for this tool
PDF GuidesWhat Does "Flatten a PDF" Mean, and When Should You Do It?Flattening turns form fields, comments, stamps and signatures into a fixed part of the page. Learn when to flatten, the two ways to do it, and the mistakes to avoid before sending a filled form.
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Privacy & Security"Are Online PDF Tools Safe? How to Protect Your Private Documents"Most online converters upload your files to a server. Learn the risks, how browser-based tools differ, how to check what a site does with your file, and a privacy checklist.
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PDF GuidesHow to Add a Watermark to a PDF (Text or Logo)Stamp CONFIDENTIAL, DRAFT or your logo on every page of a PDF. Learn which position, transparency and layer to use, and what watermarks can and cannot protect.
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