Defense in depth. This is a term that is well known and familiar in my profession, business and data security. What does it mean?
Simply put, defense in depth means using more than just one means to protect yourself. In case one fails, you’ve got the other ones to rely upon.
Defense in depth is all around us. Consider safety systems in cars: seat belts, air bags, energy-absorbing bumpers, and anti-lock brakes. This is a defense in depth that protects passengers from harm in the event of a collision. Or, the multiple walls, fences and other barriers in a fortress.
Similarly, you can practice a defense in depth to protect your computers and the information stored in them. I recommend you use the following:
Locking screen saver
Cable locks (for laptop computers)
Screen filter (for laptop computers)
None of these gives you complete protection, and each protects in a slightly different way. But they work together to protect your system and your information from unauthorized disclosure and loss.