Password Protect PDF – Encrypt PDF Online Free
Add a password to your PDF and lock it from unauthorized access. Encrypt any document securely in your browser – no sign‑up, no uploads, works offline.
Make sure you remember the password – there is no recovery.
How to Password Protect a PDF
Locking your PDF with a password is simple and takes only a few clicks:
- Upload your PDF – Drag and drop the file onto the upload area, or click to browse.
- Create a strong password – Enter a password (at least 4 characters) and confirm it. The tool will encrypt the PDF with this password.
- Encrypt and download – Click “Encrypt & Download”. The protected PDF is saved directly to your device. Nobody can open it without the password.
All encryption happens locally in your browser. Your original file is never uploaded to any server, so it stays completely private.
What Is PDF Encryption?
PDF encryption transforms your document into a secure format that requires a password to open. Our tool uses the AES‑128 encryption algorithm, which is the industry standard for protecting sensitive documents. When you set a password, the PDF content is scrambled, and only someone with the correct password can decrypt and view it. This is essential for:
- Confidential business reports
- Personal financial documents
- Legal contracts
- Any file you want to keep private
Even if someone gains access to your computer or cloud storage, they won’t be able to open the PDF without the password.
Why Use Nyxbo’s Password Protect PDF Tool?
- 100% free – No subscription, no hidden costs.
- Privacy first – Your PDF never leaves your device. Encryption is performed locally in your browser.
- No sign‑up – Just upload, encrypt, and download.
- Works offline – After the page loads, you can continue encrypting PDFs without an internet connection.
- Strong encryption – Uses AES‑128 encryption, the same standard trusted by governments and banks.
Frequently Asked Questions
How do I password protect a PDF for free?
Upload your PDF to our tool, set a password, and click “Encrypt & Download”. The process is free, instant, and completely private.
Can I encrypt a PDF without Adobe Acrobat?
Yes, our tool works entirely in your browser — no software installation required. It’s a perfect free alternative to Adobe Acrobat.
Is my PDF uploaded to a server?
No. Encryption happens client‑side. Your file never leaves your device, so it remains 100% private.
What encryption algorithm is used?
We use AES‑128 encryption, which is a modern, secure standard for PDF protection.
Can I remove the password later?
To remove a password, you need the original password. Use our Remove PDF Password tool to unlock it.
Does this tool work on mobile?
Yes, the interface is fully responsive and works on iOS and Android devices.
Is there a file size limit?
The tool works best with files up to 100 MB. Larger files may take longer to process depending on your device.
What if I forget the password?
There is no way to recover a lost password. Keep it in a safe place; we cannot help you decrypt the file.
Can I restrict printing or copying?
The encryption includes basic permissions (e.g., preventing modification), but for advanced restrictions you may need a dedicated PDF editor.
Is this tool completely free?
Yes, no payments, no sign‑up. You can encrypt as many PDFs as you need.
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