I learned my most important computer security lesson from an absent-minded redhead.

Years ago, the redhead needed some help adding memory chips to her computer. It's a 15-minute job, fast and easy. Besides, I had a thing for redheads.

My lesson in computer security began the moment I sat down at her computer. There was a yellow sticky note attached to the monitor. The note gave her user name and password.

That was lesson No. 1. You wouldn't need to be a world-class hacker to break into her e-mail account. Any plumber, electrician, rug cleaner, friend or relative who got close enough to that computer just needed to read at a third-grade level to log on to her account.

Maybe you'd never tape your password to your computer monitor. But don't get smug yet. Lesson No. 2 may hit closer to home. Her password was her last name.

Ask any security expert and you'll find that folks commonly use birthdays, the name of a wife, son or a daughter, a pet's name, or even --- my very favorite --- "password" as the password.

The newspapers are filled with stories of elaborate schemes --- called phisher sites --- used by computer criminals to capture passwords. But often there's no need to fish for passwords; they jump right into the boat.

There are people out there who worry about the safety of their computer and e-mail accounts and --- wisely --- spend money on firewall software and computer routers. Yet they do something stupid when it comes to a password.

The temptation is great to create no-brainer passwords. Most of us have a lot of them to remember: the e-mail account at home; the log-on to the computer network at work; perhaps another for your online bank account; and still others for Web sites such as Amazon or eBay.

But excellent advice is to not only make a password hard to figure out but also to change it every six months. So imagine that you have four passwords and change each of them twice a year. Not fun, I admit. It's easy for me to understand the difficulty since I often spend the morning looking for my car keys or my wallet.

There are computer programs and security devices designed to help. But since most of you won't buy or use those programs, we'll talk about ways to do this yourself.

Let's go over some of the rules for passwords. As we go along, I'll do my best to help you create passwords that are both secure and possible to remember.

> A password should not be a word.

That makes things too easy for automated hacker software. Some programs available on the Net use what is called dictionary attack to break into a password-protected account. They literally try every word in the dictionary.

> Adding numbers or symbols to the password makes it more secure.

Such combinations put the password way beyond the capabilities of hacker programs designed to guess passwords. So the perfect password would look something like this: 8rtrnrd25.

> Random numbers and letters are difficult to remember. But there are ways to have a hidden order to the arrangement of letters and numbers that makes it easy to remember. I'll tell you how I do it.

Look at the letters in the password I gave as an example: rtrnrd. That's the first letters from the song title "Rudolph the Red-nosed Reindeer." It's easy for me to remember since it's the only song I can sing, much to my family's dismay. So I only need to remember the numbers. In this case, those numbers are part of a telephone number assigned to me many years ago.

That solves part of the problem of creating a password that is hard to crack yet easy to remember. But I'm still left with the need to create two or three more passwords, making them equally random and yet easy to remember. After all, I don't want to follow the redhead's example of pasting my passwords on my computer monitor.

I can thank Rudolph for the answer. I simply use other lyrics from the same song for the letters in my next password. So "had a very shiny nose" translates to havsn. Then the numbers can come from the next part of that telephone number from years ago.

The good thing about my system is that it's easy to modify to suit your own memory. For instance, instead of a song, you could use a poem you memorized in the sixth grade, a book title or any other phrase that sticks in your mind. Numbers are just as easy and relatively safe as long as the telephone numbers and street addresses you use come from your distant past.

And, by the way, the redhead wasn't dumb for writing down her passwords in case she needed a reminder. Just stash them somewhere away from the computer.

tecbud@ajc.com