Free Password Protect PDF
Add a password to a PDF so only people who know it can open it. AES-256 encryption, done in your browser, nothing is uploaded.
Choose a PDF and type a password twice. Your browser scrambles the file with AES-256 and gives you a protected copy that asks for the password before it opens. The file and the password never leave your device.
How to use the Password Protect PDF
- Choose your PDF. Pick the file you want to protect. It opens in your browser and is not uploaded.
- Set a password. Type the password twice. Longer is stronger, and a few unrelated words work well.
- Download the protected copy. The new file asks for the password before it opens. Open it once to check, and keep the original somewhere safe.
What is the Password Protect PDF?
A password on a PDF means the file stays scrambled until someone types the password. Without it, the pages, text and images cannot be read, even by a person who gets hold of the file.
This tool adds that password in your browser using AES-256, the strongest standard encryption defined for PDF. Your file is never uploaded, so the unprotected original and the password stay on your device.
How the protection works
The tool uses the standard PDF security handler with AES-256 (PDF 2.0, revision 6). Your browser turns the password into an encryption key and scrambles every page, image and text string in the file. Anyone who opens it later needs the password, and PDF readers ask for it automatically.
Most current PDF programs can open AES-256 files. Very old programs may not, so test the protected file with the program the other person uses.
Open password and owner password
The password you type first is the one needed to open the file. Under the optional settings you can also set an owner password and choose whether printing, copying text and editing are allowed. If you leave the owner password empty, a random one is used that nobody knows, so the restrictions cannot be changed later with this file alone.
Restrictions are a request to the program opening the file. Some programs ignore them, so do not rely on them to stop someone who has the password.
What this does not do
- It does not hide the file name or its size.
- It does not stop a person who knows the password from sharing the contents.
- It cannot be undone without the password. If you forget it, nobody, including us, can open the file.
- It is not a digital signature and does not prove who created the document.
When it is worth protecting a PDF
- Payslips, tax forms and bank statements before you email them.
- Contracts and ID copies you send to someone you do not know well.
- Medical or legal papers that you keep in cloud storage.
- Any file you share through a channel you do not control.
To remove a password later, use Unlock PDF.
Tips for better results
Use a long password, such as four unrelated words, rather than a short one with symbols.
Send the password by a different route than the file, for example the file by email and the password by message.
We cannot recover a lost password. Store it in a password manager and keep an unprotected original.
Restrictions such as no printing depend on the program that opens the file, and some ignore them. The password to open the file is what protects it.
Related tools
Privacy and where your data goes
This tool runs entirely in your browser. The PDF and the password are used on your device to encrypt the file and are never sent to Signplify. We cannot see them and cannot recover the password for you.
Frequently asked questions
How strong is the protection?
It uses AES-256 encryption, the strongest standard encryption defined for PDF. The weak point is usually the password, so choose a long one that you do not use anywhere else.
Can you recover my password if I forget it?
No. The password is never sent to us and the file cannot be opened without it. Keep it in a password manager.
Will the person I send it to be able to open it?
Yes, if their PDF program supports AES-256, which most current programs do. Very old programs may not, so check with the program they use.
Are the printing and copying restrictions secure?
Not completely. They depend on the program that opens the file, and some ignore them. The password to open the file is the real protection.
Is my file uploaded?
No. The file and the password stay in your browser.
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