Password protect a PDF for free using AltoProtectPDF

Protect your PDF from being edited without having to register an account or install an application. Create and apply a password for free
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File extension .pdf
Internet media type application/pdf
Description: The Portable Document Format (PDF) is a vector-based file format introduced by Adobe Systems in 1993. It was primarily designed for opening and editing documents on various desktop and mobile devices regardless of the operating system installed. PDFs can contain both text and images. Every page of a PDF file has a fixed layout and retains its structure when shared, printed, or downloaded to another device.
Technical Details: A PDF is a 7-bit ASCII file. It is based on the PostScript language and contains the description of a flat document with a fixed layout and all the embedded elements, such as graphic objects and fonts (in case the file includes text sections). PDF documents may also contain fillable fields, as well as interactive elements, i.e. hyperlinks, bookmarks, buttons, etc.
Developed by ISO
Initial Release: 15 June 1993
Useful links:



Review the brief guidelines below on how to password-protect a PDF for free in seconds

  1. Visit in any browser.
  2. Use the Drag & Drop feature or click Choose File to upload a document.
  3. Wait while your document uploads.
  4. Think of and enter a unique code.
  5. Click Protect File Now! to apply the password to the file.
  6. Download your protected PDF.
  7. Repeat this process with other documents by clicking Start over again.

The Supreme Features Comparing Chart

Compare AltoProtectPDF to other solutions on the market for document encryption and choose the service that suits you best. To save time, just take a look at the chart below and review the features you need for better online document management and security.

Split PDF βœ” βœ” βœ”
Merge PDF βœ” βœ” βœ”
Combine & Reorder βœ” ❌ ❌
Extract Pages βœ” ❌ ❌
Compress PDF βœ” βœ” ❌
Rotate PDF βœ” βœ” ❌
No software downloads βœ” βœ” ❌
Cloud storage Unlimited No info No info
Price Free Free 7-Day Trial paid Free 7-Day Trial paid
Encryption and security βœ” βœ” βœ”
Support 24/7/365 No info βœ”
No ads βœ” βœ” βœ”



A true salvation for me. Some documents contain sensitive data, so I have to search for a tool that could protect them. AltoProtect does everything! I can rely on it entirely.



Due to my job all of the documents I deal with contain people’s personal information that cannot be disclosed. AltoProtect handles this effortlesly. And it’s fast, reliable and free!



I highly recommend this tool for those who need data security while working with sensetive data. Creating passwords for documents is so easy now. I can make up a separate combination to protect each file. It’s great!

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How to Protect PDF Files

Add extra protection to the documents with sensitive data using our online solution. Password protect your docs unlimitedly from the smartphone or computer.

How to password protect PDFs online

If you’re looking for the fastest way to protect your PDFs for free, our online solution comes in handy. AltoProtectPDF allows you to apply encryption regardless of your device. Using a strong internet connection, protect your PDFs from being edited without your consent. 

Take a look at our step-by-step instructions on how to password protect PDFs online:

  1. Go to AltoPasswordPDF via your preferred browser.
  2. Click Choose File or upload a document from your device or cloud storage.
  3. Create a password and enter it.
  4. Click Protect File Now! to save the changes.
  5. Download the encrypted PDF or send it out.

You can upload and protect as many documents as you want. Plus, AltoProtectPDF provides you with the most reliable third-party-prevention methods. Once you’ve protected and downloaded your PDF, it’s deleted from our server. Lock and share your documents, knowing that all your data is secure and well-protected. Try it out now and say goodbye to expensive apps and time consuming steps.

BackgroundHow to password protect PDFs online


AltoProtectPDF is a free online solution for PDF encryption. Upload a document and apply a password without paying a penny. Use the service regardless of the device you’re on and protect your data.