Include a good variety of symbols, letters and numbers in the passphrase, and change it regularly--monthly, if not weekly. Don't use words you might find in a dictionary, or any words that are constructed cunningly by replacing letters with numbers (that is, passwords like "n1c3"); hackers are way ahead of you on such "substitution" tricks.

are effectively impossible for computers to guess by brute force, even by cloud computing systems running Roth's software, due to the amount of time it would take.

Because WPA-PSK is also calculated using the service set identifier (SSID, or base station name) of the wireless router, it also makes sense to personalize this and ensure it isn't using the default setting (usually the manufacturer's name). This will protect you against so-called "rainbow" attacks, which rely on a look-up table of common SSIDs.

Keir Thomas has been writing about computing since the last century, and more recently has written several best-selling books. You can learn more about him at and his Twitter feed is .