TinySandyFree Online Tools

PDF Password Protection Utility

Add a password to a PDF so it cannot be opened without it. The file is encrypted in your browser with AES-256 or AES-128, the same standard encryption that desktop PDF programs use, and you can also switch off printing, copying or editing for people who open it. Your document and your password never leave your device.

PDF Tools Runs in your browser

Protect Your PDF with a Password

Use this only on documents you own or are authorised to protect. If you forget the password, nobody can recover the file, including this site.

Drag and drop a PDF here, or click to browseAccepted: PDF. Up to 100 MB.
Standard keyboard characters only.
Needed to change the restrictions later. Leave blank and a random one is generated for you; it must differ from the opening password.

How to Use the PDF Password Protect

  1. Choose the PDF you want to protect.
  2. Type the password twice. Optionally add an owner password and untick the permissions you want to restrict.
  3. Pick AES-256 (recommended) or AES-128 if the recipient uses an older PDF reader.
  4. Press Protect PDF and download the encrypted file. Open it once yourself to confirm the password works before you send it.

About This Tool

People sending contracts, payslips, ID scans or medical letters by email, and anyone who wants a quick way to put a password on a PDF without installing software.

Input: PDF  ·  Output: Encrypted PDF.

Features and Limitations

Features

  • Real PDF encryption (AES-256 revision 6 or AES-128), not just a flag.
  • Optional owner password plus printing, copying and editing permissions.
  • A random owner password is generated if you leave the field blank, so the restrictions cannot be undone with the opening password.
  • Text stays selectable for screen readers (accessibility extraction is always allowed).
  • Everything happens locally; no upload, no account.

Limitations

  • There is no password recovery. If you lose the password the document cannot be opened.
  • The open-password is the real protection. Print, copy and edit restrictions are requests that compliant viewers honour; some programs ignore them.
  • AES-256 files need a reasonably modern reader (Acrobat X or later and current browsers). Choose AES-128 for older software.
  • Passwords may use standard keyboard characters only; accented or non-Latin characters are rejected because viewers treat them inconsistently.
  • PDFs that are already encrypted must be unlocked first. Requires a current browser with the Web Crypto random generator.
  • Processing happens on your device, so very large files depend on your browser's available memory.

Example

Protect a payslip with the password Blue-Heron-2291, keep printing allowed, and untick copying. The recipient needs the password to open it and cannot copy text in compliant viewers.

Frequently Asked Questions

How secure is the protection?

With a long, unique password AES-256 encryption is considered strong. The weak point is nearly always the password itself, so use a long one and share it through a different channel from the file.

What is the owner password?

PDFs can have two passwords. The user password opens the file; the owner password lets someone change permissions. If you leave it blank we create a random one and show it in the result, so keep it if you may need to lift the restrictions later.

Will every PDF viewer respect the restrictions?

No. Printing, copying and editing limits depend on the viewer being well behaved. They deter casual use, but the password to open is the only strong barrier.

Is my PDF or password uploaded?

No. Encryption runs entirely in your browser; neither the file nor the password is sent anywhere.

Can I remove the password later?

Yes, with the PDF Unlock tool, as long as you know the password. We cannot recover or guess forgotten passwords.

Related Tools

More like this: all PDF Tools tools, all Files & Documents tools or the TinySandy home page.