Oracle PL/SQL for DBAs

Introduction to Encryption

Let’s suppose that you carry your laptop home from work every day, bring it back to the office the following morning, and then tether it to your desktop with a locking cable protected by a combination lock. You know how important it is to remember the lock combination, don’t you? If you ever forget it, your laptop will end up married to your desk until you pry it free by cutting the cable. Maybe you remember numbers easily, but I don’t. It’s hard enough for me to even remember my own telephone number, let alone the plethora of secret numbers in my life—my Social Security number, bank account PIN, voice mail password, and anniversary (oops!). To make things easier, I have devised an ingenious method for remembering that lock combination—I have written down the code on a label and put that label on the lock itself!

And now you must be wondering if you would ever be able to trust me with something secure!

Like the rest of humanity, I have a brain that is part hard drive (disk) and part random-access memory (RAM), and numbers seem to go into RAM more often than not. After a period of usage, the numbers are conveniently aged out to make room for more (not unlike the System Global Area of an Oracle instance) and are forgotten. In computers, this process is expected and is built into the design. Database systems are designed to store information and make it accessible to users when asked. Historically, the assumption has been that users who demand access will ...