Protect PDF with Password
Password-protect a PDF with AES encryption in your browser — free, fast and private.
How to use Protect PDF with Password
- Choose a PDF file.
- Set and confirm a password.
- Click Encrypt & Download — you get an AES-encrypted .enc file.
- To open it later, use the Unlock PDF tool on this site with the same password.
Note: this tool runs in your browser. Nothing is uploaded.
Honest limit: Browsers cannot apply standard PDF (128-bit) encryption, so this tool AES-encrypts the whole file into a .enc file instead of a standard password-protected PDF. Adobe Reader will not prompt for its password — decrypt it with the Unlock PDF tool.
Frequently Asked Questions
Is Protect PDF free?
Yes, it is 100% free with no sign-up.
Will Adobe Reader ask for the password?
No — and that is important to know. Browsers cannot apply standard PDF encryption, so this tool AES-encrypts the whole file instead. The result is a .enc file, not a standard password-protected PDF.
How do I open the encrypted file?
Use the Unlock PDF tool on this site and enter the same password — it decrypts the file back into a normal PDF.
Is my file uploaded?
No. Encryption happens entirely in your browser.