Security and Usability: Keep It Simple

If you're not thoughtful about your approach to balancing computer security with computer usability, you may end up with neither

June 01, 2004 — CSO — One of the hardest things about computer security is making the so-called secure computers easy to use. Indeed, building computers that are both secure and usable is so difficult that many IT professionals believe that security and usability are antagonistic goals that must be balanced.

Think, for example, about passwords. Computers without passwords are easy to use, but not very secure; anyone who sits down at the machine's keyboard or logs on over the network can access anything he wants. However, access controlslong, difficult-to-guess passwords that prevent the bad guys from breaking in and learning the computer's secrets—make computers difficult to use. So organizations naturally weigh security needs against user convenience.

The problem with this balancing act is that it often produces systems that are neither secure nor usable. The extremely usable system without passwords won't be much use if somebody breaks in and deletes all of its files. And the secure system with the hard-to-guess passwords won't be very secure after users post their passwords on little yellow stickies.

One reason that security traditionally has been viewed as the enemy of usability has to do with the way that security was incorporated into many traditional computing environments. Until very recently, security was frequently an extrasomething added to existing operating systems and applications. Want to encrypt your business plan? Start with a word processing application, save the document in a file, then go back to that file and encrypt it with a file encryption program to add the missing security. Of course, the deleted copy of the business plan is still floating around on your hard disk, so you also have to run a special program to sanitize the hard disk.

All of these extra steps take work and require training. Make a mistake, and you might unknowingly compromise the system's security or, even worse, wipe out your data.

Today, features like file encryption and disk sanitization are built directly into applications and operating systems. The result is that using cryptography to protect a document is now much easier. For example, both Microsoft Word and Adobe Acrobat let you put a "password" on a file when you save it. This so-called password is actually used to generate an encryption key that, in turn, is used to encrypt your document. When you go to open the file, the application sees that the file has been encrypted and prompts the user for the password once again. A valid password can be used to decrypt the file, while an invalid one results in gibberish.