Protect PDF

Secure your PDF documents with password protection and encryption. Set open passwords, permission restrictions, and choose encryption strength. Keep sensitive documents safe.

100% Private — files never leave your browser

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Select Files

Configure

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0/3 free today

Drop your PDF to protect with a password

or click to browse from your device

Select Files

Your files stay on your device — 100% private

PDF, APPLICATION/PDF

How it works

Upload your file

Drag & drop or click to select. Files stay on your device — nothing is uploaded.

Adjust settings

Configure options and preview before processing.

Download result

Get your file instantly. No signup, no email required.

Frequently Asked Questions

You set a password that recipients must enter to open the PDF. The document is re-saved with security metadata applied entirely in your browser.

Yes — you can control whether the recipient can print or copy text from the protected PDF.

There is no way to recover a forgotten password. Make sure to save it in a secure location.

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What Is PDF Password Protection?

PDF password protection encrypts a PDF document so that only people with the correct password can open and view it. This is the standard way to restrict access to confidential documents, preventing unauthorized viewing, printing, or copying of sensitive content.

PDF encryption uses industry-standard algorithms (AES-128 or AES-256) to secure your documents. You can set an open password that recipients must enter to view the document, and optionally set a separate permissions password that controls whether the document can be printed, copied, or edited.

One23PDF's protection tool encrypts your PDFs entirely in your browser. Your documents and passwords are never sent to any server, eliminating the risk of interception or unauthorized access during the protection process. It's 100% free with no credit card, no file size limits, and no restrictions on the number of documents you can protect.

Benefits of Protecting PDFs with One23PDF

Restricted Access

Only people with the password can open your document. Keep confidential reports, contracts, and personal files safe from unauthorized viewers.

Prevent Copying

Set permissions to prevent copying, printing, or editing of your PDF content. Control exactly what recipients can do with your document.

Industry-Standard Encryption

One23PDF uses AES encryption — the same standard used by banks and governments — to secure your documents. Your protection is robust and widely recognized.

Local Processing

Encryption happens entirely in your browser. Your documents and passwords never leave your device, ensuring the protection process itself is completely secure.

How to Password Protect PDFs with One23PDF

1
Upload Your PDF
Drag and drop the PDF you want to protect or click to browse. One23PDF accepts documents of any size and page count.
2
Set Password & Permissions
Enter your desired password and choose permission settings — control whether the document can be printed, copied, or edited. Set different passwords for opening and permissions if needed.
3
Download Protected PDF
Click protect and download your encrypted PDF. The document now requires the password to open and respects the permissions you configured.

Common Use Cases for PDF Protection

Securing confidential business reports and financial statements
Protecting client deliverables and proposals from unauthorized distribution
Encrypting HR documents with employee personal information
Securing legal files and contracts during transit
Protecting medical records and patient information for compliance
Password-protecting tax documents and financial records

One23PDF vs. Other PDF Protection Tools

Adobe Acrobat Pro provides comprehensive PDF protection but costs $19.99/month. Free online protection tools like SmallPDF and Sejda encrypt your documents on their servers — which means your supposedly confidential content is being processed by a third party, potentially undermining the very security you're trying to achieve.

One23PDF encrypts PDFs entirely in your browser using industry-standard AES encryption. Your documents and passwords never leave your device, making the protection process itself completely secure. There's no subscription, no account, and generous daily limits.

For organizations handling sensitive data — law firms, healthcare providers, financial institutions, HR departments — One23PDF provides the security of local encryption with the convenience of a web-based tool. You don't have to choose between security and accessibility.