Protect PDF
Add or remove a password with AES encryption and permission controls - 100% in your browser.
Drop a PDF here
or click to browse
About this tool
Password Protect a PDF
You need to email a tax return, share a medical report, or send a contract — but first, you want to lock it with a password so only the intended recipient can open it.
Here is the problem with most "protect PDF" tools: you upload your unencrypted document to their server, type your password into their form, and trust that they will encrypt it and forget both. That defeats the entire purpose of encryption. Your sensitive file and your password were both exposed to a third party.
KuroPDF encrypts your PDF entirely in your browser using a WebAssembly build of qpdf — the same battle-tested library used in enterprise document workflows. Your file is never uploaded. Your password is never transmitted. The encryption runs on your device and the encrypted output downloads directly.
You can choose between AES-256 (recommended for maximum security), AES-128 (compatible with older readers), or RC4-40 (legacy only — not secure, but required by some ancient systems). You can also set granular permissions: allow or block printing, copying text, editing, and form filling independently.
The result is a standards-compliant encrypted PDF that opens in any PDF reader. Share it via email, Slack, or cloud storage, and only people with the password can access the contents.
How to use
- Drop your PDF
Load the PDF you want to protect. It is parsed locally — your unencrypted document never touches a server.
- Set a strong password
Enter a password. Use something long and unpredictable. The tool shows password strength. Consider a passphrase like "correct-horse-battery-staple" for memorability.
- Choose encryption level
Select AES-256 for maximum security (default), AES-128 for wider compatibility, or configure permissions (print, copy, edit) independently.
- Download the encrypted PDF
Click protect. The encrypted file downloads immediately. Share it via any channel — only the password holder can open it.
Encrypt a PDF
Secure sensitive PDFs with strong encryption before sharing or storing them.
Because it is local, your confidential documents stay confidential.
Remove a Password from a PDF
Have a PDF that asks for a password every time? If you know the password, remove it for good.
Decryption happens locally - your file and password are never uploaded.
Frequently asked questions
How strong is the encryption?
AES-256 is the gold standard used by governments, military, and financial institutions worldwide. It is computationally infeasible to crack with current or foreseeable technology.
Does my password get sent anywhere?
No. Encryption runs entirely in your browser via WebAssembly. The password and file never leave your device. There is no server involved in the process.
Can I set different permissions (print, copy, edit)?
Yes — you can independently allow or block printing, text copying, editing, form filling, and annotation. These permissions are enforced by PDF readers that respect the standard.
Will the recipient need special software to open it?
No. Any standard PDF reader (Adobe Reader, Preview, Chrome, Firefox) can open password-protected PDFs. The recipient just needs the password you share with them.
Can I also remove a password from a PDF?
Yes — the same tool can decrypt a PDF if you know the current password. Enter the existing password and download an unlocked copy.
Is AES-256 compatible with all PDF readers?
AES-256 works in Adobe Reader 9+ and all modern readers (2008 onwards). For older software, use AES-128 or RC4-40 — though RC4 is no longer considered secure.
What encryption is used?
AES-256 by default, with AES-128 and RC4-40 options for compatibility.
Is it private?
Everything runs locally in your browser using WebAssembly. Because no data is uploaded to a cloud server, your files remain strictly private, and the entire process generates zero server carbon emissions, making it highly eco-friendly.
Do I need the password?
Yes. This removes protection from PDFs you can already open with the correct password; it is not a password cracker.
Can it unlock a PDF without the password?
No - you must know the password. This is not a cracking tool.
Is this HIPAA compliant?
KuroPDF processes everything locally - no data is transmitted, stored, or accessible by any third party, which supports HIPAA data minimization principles.
Does this work on iPhone?
Yes - KuroPDF works in any modern browser on iPhone. No app download required.
Does this work on Android?
Yes - KuroPDF works in any modern browser on Android. No app download required.
Does this work on Mac?
Yes - KuroPDF works in any modern browser on Mac. No app download required.
Does this work on Chromebook?
Yes - KuroPDF works in any modern browser on Chromebook. No app download required.
Does this work on iPad?
Yes - KuroPDF works in any modern browser on iPad. No app download required.
Does this work on Windows?
Yes - KuroPDF works in any modern browser on Windows. No app download required.
How do I password protect a PDF?
Open the tool, drop your file, adjust any settings, and click the action button. The result downloads to your device instantly.
Do I need to create an account?
No - KuroPDF is completely free with no sign-up required.
Are my files uploaded?
Everything runs locally in your browser using WebAssembly. Because no data is uploaded to a cloud server, your files remain strictly private, and the entire process generates zero server carbon emissions, making it highly eco-friendly.
How do I remove a PDF password?
Open the tool, drop your file, adjust any settings, and click the action button. The result downloads to your device instantly.
How do I encrypt a PDF?
Open the tool, drop your file, adjust any settings, and click the action button. The result downloads to your device instantly.