converteo.app

Protect PDF with Password

Encrypt a PDF with a password — processed in your browser

Processed in your browser — 100% private

Password-protecting a PDF is one of the simplest ways to add a layer of confidentiality: contracts, invoices, medical results and HR documents should never be forwarded in plain form. Our tool encrypts your PDF with AES-256 using a password you choose, directly in your browser — the password never travels over the network, because nothing is uploaded. Recipients open the PDF in any viewer (Adobe Acrobat, Preview, Chrome, Edge) by entering the password.

How to password-protect a PDF

  1. Drop the PDF you want to protect into the window.
  2. Enter a strong password twice to confirm.
  3. Click "Protect PDF" and download the encrypted file.

Supported formats

Input: any standard PDF. Output: AES-256 encrypted PDF compatible with all major viewers.

Why protect with converteo.app

  • Your password never leaves your device — we couldn't read your file even if we wanted to.
  • Industry-standard AES-256 encryption.
  • No account, no file size limit, no watermark.
  • Works offline once the page is loaded.

Protect PDF — Frequently asked questions

What happens if I forget the password?
We can't recover it. The password is never transmitted to or stored by us. Pick a password you can remember — or store it in a password manager.
Which PDF viewers accept this encryption?
All major viewers: Adobe Acrobat, Apple Preview, Chrome's built-in PDF viewer, Edge, Firefox, Foxit, and most mobile apps.
How strong is the encryption?
We use AES-256, the same algorithm used for classified government documents. Brute-forcing a strong password against AES-256 is computationally infeasible.
Is my file uploaded?
No. Encryption happens entirely in your browser using @cantoo/pdf-lib. Your file and password stay local.