Protect PDF
Protect PDF files online for free. Add password protection, restrict access, and secure your PDF document in your browser.
Drop your PDF file here
Max file size: 50 MB
Uploading...
Securing PDF file...
Applying password encryption algorithms. Please wait.
PDF Protected!
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Secure
Your files are transferred and processed securely over encrypted HTTPS.
Fast
Protect your PDF files in seconds with our high-performance servers.
Easy to Use
Simple and intuitive interface makes protecting PDFs easy and quick.
Protect PDF Files Online
Use MarsPDF to password protect PDF files online for free. Our browser-based security tool lets you add strong encryption to your PDF documents to restrict access, prevent editing or copying, and download your secured file safely in seconds. No registrations or desktop installations are required.
Whether you have financial sheets, private legal agreements, personal medical scans, or design drafts, you can easily restrict actions and shield sensitive information from unauthorized eyes directly inside your web browser.
How to Protect a PDF
Upload Your PDF
Drag and drop or select the PDF document you want to secure from your device.
Set Restrictions
Enter an open password, or switch to permission protection to check checkboxes restricting print, edit, and copy actions.
Secure & Download
Click "Protect PDF" to apply standard security metadata and download your secured PDF instantly.
Add Password Protection to PDF
Prevent unauthorized people from opening your documents. By setting an open password (user password), anyone trying to open the file will be prompted to enter the correct code.
MarsPDF uses standard cryptographic encoding algorithms to wrap your PDF files, ensuring they remain encrypted and protected when sent by email or uploaded to cloud storage platforms.
Restrict PDF Permissions
If you want people to be able to read your PDF document but prevent them from altering or stealing the contents, you can configure permission protection (owner password).
Our tool lets you toggle granular restriction flags, including:
- Prevent Printing: Blocks printing actions so users cannot create physical copies.
- Prevent Editing: Restricts changes to text, images, page order, and other content structures.
- Prevent Copying: Disables selection and copying of text, graphics, and annotations.
- Prevent Annotating & Form Filling: Blocks adding notes, markings, or inputting data into form fields.
Why Protect PDF Files?
PDF files are the standard for distributing official documents. However, sending unchecked contracts, invoices, corporate books, or certificates leaves them vulnerable to unauthorized alterations and text copying.
By encrypting the file, you guarantee the integrity of your layout and restrict reader actions to only what you permit.
Secure Online PDF Protection
Your privacy and document security are fully guaranteed. All files uploaded to MarsPDF are transferred and processed securely over encrypted HTTPS connections.
We do not store, review, or share your passwords or files with any third party. Your documents remain completely private.
Frequently Asked Questions
Is the Protect PDF tool free to use?
Yes. MarsPDF offers this online security tool completely free for any user with no registration required.
What is the difference between open and permission passwords?
An open password prevents unauthorized users from opening and reading the PDF document. A permission password allows users to view the file but restricts actions like printing, editing, and copying.
Can I restrict copy-pasting text from my PDF?
Yes. By enabling permission protection and selecting "Prevent copying", users will not be able to select or copy text and images from your file.
Are my passwords secure?
Yes. We do not store or track the passwords you enter. Passwords are used solely to encrypt the PDF file and are processed instantly under secure HTTPS connection.
How long are my files kept?
All files are processed securely and are not stored or retained on our servers.