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Category: PDF tools

Encrypt PDF

System ideaMissing a tool?

Password-protect a PDF locally with AES-256 or RC4, then download it

Add a password and permission restrictions to an unencrypted PDF, then download the protected file. Encryption runs entirely in your browser; the password is never uploaded.

No file selected.

Choose an unencrypted PDF to password-protect.

The password never leaves your device: encryption runs entirely in your browser, and the password is never stored, logged or sent anywhere.

Everything on this page is processed in your browser. Nothing is uploaded.

What this tool does

The password you set becomes the PDF's own "document open" password, using the same AES-256 (or, if chosen, RC4) standard security handler built into the PDF format, so the protected file opens in Adobe Acrobat, Chrome, Firefox and other compliant readers exactly as a PDF encrypted by desktop software would. An optional owner password controls the permission flags (printing, copying, editing, annotating) independently of the password needed to open the file; leaving it blank reuses the open password for both. This tool refuses to re-encrypt a PDF that already has a password, since doing so without first removing the existing protection would leave the file's contents unreadable under any password.

How to use it

  1. Choose an unencrypted PDF file.
  2. Enter a password, and optionally a separate owner password and permissions.
  3. Press Encrypt PDF and download the protected file.

Privacy

This tool runs entirely in your browser. Your input is never uploaded, stored or shared — closing the tab removes it.

Frequently asked questions

Which encryption mode should I choose?
AES-256 unless you specifically need to support a very old PDF reader; it is the stronger, modern option and opens in every current PDF viewer.
What do the permissions actually control?
Flags a compliant reader checks before allowing printing, copying or editing. They are enforced by well-behaved software, not a cryptographic guarantee, so the password is still what actually protects the content.
Can I encrypt a PDF that is already password-protected?
No. Unlock it first, then encrypt the result; re-encrypting an already-encrypted file without removing its existing protection would corrupt it.
Is my password uploaded anywhere?
No. Encryption runs entirely in your browser tab; the password is never stored, logged or sent to a server.

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