One advantage that PDF documents have over other image files (i.e. TIFFs or JPGs) is the ability to secure the document. You can limit a user’s ability to copy text from a PDF document, or even prevent a user from printing (which some people rightly complain about). But there are other, more significant, uses of document security that lawyers and judges should be aware of.
For example, you can secure a PDF file so that it can only be viewed if you know the document’s password. Why would this be useful? Well, for starters, let’s assume that you need to file something ‘under seal’ and you are in a jurisdiction that only allows electronic filing. The way that electronic filing works in most jurisdictions that use it is that you simply upload the file or E-mail it in to the court, at which point the document is immediately available to everyone who wants to view it. Not good if you are filing something under seal, because the whole point is to limit access to the document.
With PDF’s document security you can file a secure version of the document and then call the court to tell them the document’s password. The password could then be distributed in a secure method to everyone who is supposed to have access to the document.
Let’s use a concrete example: if you have version 5.0 or higher of Acrobat Reader you can click here [PDF: 120 KB] to view a secure PDF document. You’ll be prompted for the password, which is ‘password’. Warning: if you have version 4.0 or lower then you won’t be able to view it. This is one of the problems of security. Each version of Acrobat has an increasingly higher level of security (which is a good thing), which creates incompatibility problems. But the Acrobat Reader is free, so just download the latest version and you should be able to view the document.
Some people have even used the security of PDF to post their key information up to a website that they can access from anywhere. The sensitive information is available but not viewable unless you know the password. I’m not sure I would rely on this (because if you taunt a hacker you’ll usually find that they can break security with enough effort and time). Nevertheless, PDF’s document security can be a good thing if you use it in the right way.