A common strategy that intruders use to crack passwords is the dictionary attack. Each word in an electronic word list—the dictionary—is tried until a match is found.

If a dictionary attack is unsuccessful, intruders can use a computer algorithm that simply runs through all possible permutations of characters until the correct password is found. Such brute-force attacks can crack simple passwords in minutes, or even seconds. The key to defeating such an attack is to choose a password that takes a long time to crack.

Consider an intruder with a computer that can try ten billion combinations a second.

If you use a password that's eight characters long, consisting only of numbers, the intruder's computer can try every possible password of that type in less than a second.

If you use a password that's eight characters long and consists of only lower-case letters, that's better... however, the intruder's computer can try every possible combination in 21 seconds.

A strong password should be nine or ten characters long (or longer), and it should incorporate all four types of keyboard characters. This exponentially increases the time it takes for cracking algorithms to guess it.

If you use a password that's eight characters long and uses upper- and lower-case letters, numbers, and symbols, that intruder's computer will need more than eight days to try all of the possible combinations. Make it ten characters long, and the intruder will need years.

So how do you create a strong password that you can actually remember? One good strategy is to create a "first-character" password. Think of a phrase that you can easily remember—for example, "I met Linda at work 3 years ago!".

Take the first letter of each word in your phrase and substitute numbers and symbols to form your password: !mL@w3Ya!!

Another method is to choose four or five random words that are not often used. Dog Cat Horse Bird would be easy to crack because all of the words are frequently used. However "Yeti Skiing Nebula Sinkhole" would be much harder to crack because they are not everyday frequently used words.

Watch this YouTube video for a more detailed approach to what is good and bad. Click Here.

Why not try creating a Pass Phrase. See our FAQ on Pass Phrases.