🔒 Protect PDF with a Password

Lock your PDF so it opens only with a password — free, secure, and watermark-free.

We only use your file to generate the protected PDF.
Use at least 4 characters. Avoid easy-to-guess passwords.

Secure Your PDF in Seconds

Add an open password to keep your documents private. Upload your PDF, set a password, and download the protected file — no watermarks, no sign-up.

Frequently Asked Questions

Yes, protecting your PDF is completely free and watermark-free on SmartAssPDF.

We add an open password so the PDF can only be opened after entering the password. Your script can also apply permission settings if supported.

Files are processed securely and removed automatically after protection to safeguard your privacy.