We humans are a funny bunch. Most of us tend to hate things that are unexpected but our whole life is based around randomness. No-one knows what is coming around the corner and we just have to roll with it when it does. While randomness like that is scary it is also something to be enjoyed. Would you really live your life to the fullest if you already knew everything that was going to happen to you? Or would you just sit around and wait to die? So as you can see, randomness can be scary but in the end it can also be a good thing as well.
This is especially true when it comes to computer security. Computer security can be very fickle but one thing is a constant. If the bad guys know how you operate then you make their job a lot easier than it has to be. It takes time for the bad guys to be able to plan an attack so if you change the way your system operates just a little bit you will be able to throw them off the tracks. That is why random tends to be good when it comes to computer security.
One of the best examples of randomness being used for good when it comes to computer security is your password. Passwords that tend to use the same format are easy to guess. That is why you are always told to mix it up when you create a password. You do not want to use just letters. You want to use different kinds of alphanumeric symbols as well as numbers when you create a password. Any attempts to automate password cracking will be thwarted when you use this kind of formula.
Another good example of randomness when you are talking about computer security is how you set your system up. When a lot of system administrators set up their systems they will use the default names that already installed on the machines. The black hat hackers that are looking to attack already know this. So if you want to be able to slow them down you should change the name of all the defaults that are on your system. If it is possible change the default configuration of the system that would be great as well. A little thing like changing the port number of web software that is used can help stop you from being attacked.
Randomness can be scary but it can help you out in the long run.