What encryption strength does PDFWix use?

AES-256 (PDF 1.7 Extension Level 8) — the strongest encryption the PDF specification supports. The same standard banks and law firms require. Use a strong password (12+ characters, mixed case, numbers, symbols) to make it meaningful.

Does the password get sent to your servers?

No. Encryption runs in your browser using JavaScript and WebAssembly. Your PDF and password never leave your PC — verify in Edge DevTools (F12) > Network tab during the encrypt step.

Home / How-to

How to Password-Protect a PDF on Windows

A simple step-by-step guide to password-protect a pdf on Windows using PDFWix's free online tools.

How to Password-Protect a PDF on Windows

Password-protect a PDF on Windows 10/11 with PDFWix in your browser — AES-256 encryption, files never leave your device. Free, no install, no signup today.

Tip: use a strong password and send it separately

Use a 16+ character password with mixed case, numbers and symbols — AES-256 is computationally unbreakable with a strong password, but a 6-character dictionary word is brute-forceable in minutes. Send the password through a different channel than the PDF itself (text the password if you email the file, or vice versa) so a compromised mailbox doesn't leak both at once. If you forget the password there is no recovery — that's the point — so save it in a password manager before you encrypt.

How it works

Open PDFWix Protect PDF — Open Edge or Chrome on Windows and go to pdfwix.com/protect-pdf.
Add the PDF — Drag the PDF from File Explorer onto the dropzone, or click Select file.
Set a strong password — Type a password of 12+ characters using mixed case, numbers, and symbols.
Optionally set an owner password — Add a separate owner password to control printing and copying permissions.
Download the encrypted PDF — Click Protect PDF — the AES-256 encrypted file downloads to your Downloads folder.

Frequently asked questions

Does Windows 11 have a built-in way to password-protect a PDF?

No. File Explorer, Edge, and the free Adobe Reader cannot apply PDF passwords. Microsoft 365 Word can encrypt on Save As (AES-128), and Acrobat Pro can ($19.99/month). For free AES-256 encryption, use Protect PDF.

Can the free Adobe Acrobat Reader password-protect a PDF?

No. Adding passwords requires Acrobat Pro, which is a paid subscription. The free Reader can only open and verify already-protected PDFs.

Is zipping a PDF with a password in 7-Zip the same as encrypting the PDF?

No. Zip encryption protects the archive, not the PDF inside — once the recipient extracts the file, it's unprotected. PDF-level encryption applied by Protect PDF stays with the file even after forwarding or extraction.