Protect PDF
Add strong password encryption to your PDF documents to prevent unauthorized viewing. 100% secure browser processing.
Upload PDF
Upload the PDF you want to protect
Keep this password safe. You'll need it to open the PDF later.
How to add a password to PDF?
Upload PDF Document
Click the upload area or drag & drop the PDF file you want to protect. All processing happens safely in your browser.
Set Password
Enter a strong password. This password will be required every time someone tries to open the document.
Protect & Download
Click 'Protect PDF'. The file will be encrypted using standard AES encryption and will be ready to download.
What is Protect PDF?
Protect PDF is a free, highly secure tool that encrypts your PDF documents with a strong password. Whether you are sending confidential financial records, personal health information, or proprietary business data, adding password protection ensures only authorized individuals can open your file.
We utilize industry-standard encryption algorithms natively within your browser. Because the encryption process happens locally on your machine, your unencrypted original file and your chosen password are never transmitted over the internet, providing true end-to-end security.
Key Features
Strong Encryption
Applies standard encryption to prevent unauthorized access.
Password Security
Require a custom password to open and view the document.
Local Processing
Encryption happens offline in your browser for maximum safety.
No File Size Limits
Secure large documents without hitting server limits.
How It Works
- 1
Upload PDF
Click the upload area or drag and drop your PDF file.
- 2
Set Password
Enter your desired password. Choose a strong password with letters, numbers, and symbols.
- 3
Set Permissions (Optional)
Optionally restrict printing, copying, or editing in the permissions settings.
- 4
Protect & Download
Click "Protect PDF". The encrypted PDF downloads to your device instantly.
Common Use Cases
- ▸Protecting legal contracts before sharing with clients
- ▸Securing financial reports and confidential business documents
- ▸Protecting personal identification documents for digital storage
- ▸Restricting printing of proprietary materials or exam papers
- ▸Securing research papers and academic dissertations
- ▸Protecting copyrighted content from unauthorized editing
Supported Formats
Privacy & Security
PDF encryption is performed entirely in your browser. Your PDF content and password are never transmitted to our servers. ConvertAllNow has zero access to your documents or the passwords you set.
💡 Pro Tips
- ▸Use a strong password combining uppercase, lowercase, numbers, and symbols.
- ▸Store your password in a secure password manager — we cannot recover it if lost.
- ▸For documents shared with multiple people, consider setting different user and owner passwords.
- ▸After protecting, test the PDF by opening it in a different application to verify the password works.
Frequently Asked Questions
Frequently asked questions about Protect PDF.
We use AES-128 encryption, which is the standard for PDF security and widely supported by all PDF readers including Adobe Acrobat, Preview, and browser PDF viewers.
Yes. In addition to an open password, you can set owner-level permissions to restrict printing, copying text, editing, and annotations.
Yes. The password-protected PDF is a standard PDF file and works in Adobe Acrobat, Apple Preview, Foxit, Chrome, Firefox, and all major PDF viewers.
No. Password protection is applied entirely in your browser using JavaScript. Your files never leave your device.
Currently the tool processes one PDF at a time. Upload, set a password, and download. Batch protection is planned for a future update.
Use our Unlock PDF tool. Enter the same password you set and remove the protection when needed.
We do not store any passwords or files. If you forget the password, you will not be able to open the PDF. Always keep a record of your password.