One of the main attractions to publishing a document as a PDF file is the fact that this file is a read-only format. Since any edits to this type of document leaves a digital footprint, these files meet the legal requirements of a court of law. Not only can you track changes, you can also choose to restrict the ability for others to edit the content, even if they have PDF software of their own.
What’s more, PDF protection measures beyond a simple password-protected file that’s easily cracked using a brute force tool found on the Internet. You can completely lock the file. You have the option to protect content from being printed or copied. And you can allow everything but changes to certain sections of the file itself. Let’s take a look at the basics.
Using password protection
When it comes to security, it might seem like the password is at the foundation, however, what really protects a document, like a PDF, is encryption. When creating a file using, you have the ability to password protect the document. Simply follow the steps to create a “document open” password and your PDF software does the rest.
Behind the scenes, the encryption algorithm scrambles the file contents. Now only a person with the encryption key, or password, is able to open the file for viewing. For confidential and sensitive information, this adds an extra layer of security for information stored on a file server, sent via email or shared using other methods of file transfer. This process can help protect your publishing rights.
If your PDF software uses a strong encryption algorithm, such a 128- or 256-bit AES or 128-bit ARC FOUR combined with a good password, common password cracking tools will have an extremely hard time trying to open your file.
Protecting elements of the document
If your goal is to allow the general public to view your document but you want to prevent them from performing certain actions, most PDF software applications will allow you to create this type of security as well.
You have the option to protect a PDF document from:
- Readers editing or modifying content
- Having the content copied
- Copying done by taking a screen shot
- Adding digital signatures to the file
- Having content extracted from the file
You can also set a password to allow these actions for authorized users.
A good password
Your PDF software’s ability to encrypt the file is enough to protect the document, however, there’s still a weak link in the process—and that’s the password you create.
Simple passwords are easily guessed by a number of tools available on the Internet. Some experts stand by the strong password theory of using upper and lower case letters combined with numbers and symbols. The downside is, these types of passwords are hard to remember when you’ve got a string of characters like A6**jdhEW87. That’s why many people tend to turn regular words into strong passwords, like P@ssw0rD. Unfortunately, password-cracking tools now take these types of passwords into account, so they’re no longer a sure thing.
To adequatelydocuments that use a password, or anything else that requires a password for that matter, use a phrase instead. This makes it harder for brute force tools to guess and it’s easier to remember. Also, make sure that the password is unique; not something you’re using in another account, especially for passwords shared with anyone who has access to the document.
Many PDF software tools, like Foxit PhantomPDF, will prevent the wrong people from viewing a document but still allow search engines to see the metadata for proper indexing in the results page and ensuring your document gets found.
Even though passwords created by PDF software have the ability to completely lock down a document, professional grade applications will allow you complete control over what you hide from the public. It’s this type of complete control that makes PDF files the most practical way to secure your content.