Protect PDF with a Password — AES-256, Free, No Upload

Add a password to a PDF in your browser with AES-256 encryption. Optionally restrict printing, copying and editing. Files up to 30 MB never leave your device.

Convert in your browser · No sign-up

One PDF · up to 30 MB · encrypted on your device

Password to openRepeat password

Choose a password. Length matters most: 12 or more characters, or a few unrelated words.

Show passwords

EncryptionAES-256 (recommended) — opens in Acrobat Reader X (2010) or later, browser PDF viewers and other up-to-date readersRC4 128-bit — only for very old PDF readers

Permissions after opening

Allow printingAllow copying text and imagesAllow editing pages and contentAllow comments and form filling

Permissions are a request to the reader app. Acrobat and most viewers follow them, but some apps ignore them, and anyone with the open password can make an unrestricted copy. Only the open password actually protects the content.

Permissions password (optional)

Lets you change the permissions later in an editor such as Acrobat. Must differ from the password to open.

How to use

Choose a PDF up to 30 MB, or drop it on the page.
Enter the password twice. Optionally untick permissions such as printing or copying.
Select Protect PDF, then download the encrypted copy. The original file is not changed.

Example

report.pdf + password → report-protected.pdf, which asks for the password before showing any page.

Details and limitations

AES-256 encrypts the page content, images and metadata. The file is read and encrypted in your browser and is never uploaded. There is no way to recover a forgotten password, so keep it somewhere safe.

The PDF is rewritten during encryption, so existing digital signatures stop validating. Pages and their content are kept unchanged.

FAQ

Can I stop people from printing or copying my PDF?

You can set those permissions, and Acrobat and most viewers respect them. They are not enforced by encryption, though: some apps ignore them, and anyone who can open the file can produce an unrestricted copy.

Which password protection should I choose, AES-256 or RC4?

AES-256. It is the current PDF standard and works in all current readers. RC4 128-bit exists only for very old readers and is easy to break.

Can I use Chinese, Japanese or emoji characters in the password?

Yes, with AES-256. Make sure the people who open the file can type the same characters on their device.

Format references

Tool page updated: 2026-09-27