Cheung isn’t psychic. He had hacked into the coffee shop’s wireless Internet connection on his Toshiba laptop. It took about five minutes to do so, using free software available online.

Public Wi-Fi, or “wireless fidelity,” is very handy for perusing the Net away from the office or home. Just remember that you may have company while surfing. “When people are on a public wireless connection, they have the same expectations about privacy as when they are on the Internet at home,” said Cheung, 32, a computer security expert and an editor for TG Daily, a technology news website. “But it doesn’t work that way. Someone could be listening in.”

Cheung was using a “sniffer” program that intercepted online signals as they flew back and forth from the laptops to a wireless modem hidden somewhere amid the coffee paraphernalia. Mostly, the monitoring was limited to tracking the websites being visited. Numbers correlating to web addresses flew across Cheung’s computer screen, allowing him to see that the couple was viewing pages at a wedding-planning site. The man a few tables away started with sites selling high-speed broadband service, then went to a page about managing websites. Like a mystery yarn, the clues kept coming in.

“You start to get a story about someone,” Cheung said.

The company that provides Wi-Fi signals at Starbucks is T-Mobile USA Inc. It manages about 7,600 HotSpots nationwide, including in coffee shops, hotels and airports. T-Mobile offers a free software program, Connection Manager, to improve browsing security, said Mike Selman, the service’s marketing director. “You can use this to make sure you are connected properly to our network,” Selman said, “and that communications are encrypted from the laptop.” But the security program also seems to be more or less a secret. Not only does the name of the program not mention security, but the link to download it also is grouped with other items in a dropdown menu. If you have a Macintosh computer, you’re out of luck: The software comes only in a Windows version.

On home Wi-Fi setups, password protection can be implemented on the modem, which offers a lot of security—although some hackers say they can break through the most basic protection regimen, known as WEP. Public Wi-Fi setups, whether paid or free, don’t have the luxury of using passwords. That would defeat the purpose of allowing a great many people to use them.

Free Wi-Fi hot spots are being added to more outdoor areas everywhere. So, enjoy the freedom of Wi-Fi. But maybe you shouldn’t surf to sites you wouldn’t want people to know you’re visiting. “If you watch where people go, one site after another,” Cheung said, “it’s almost like you can read their minds.”
-David Colker (Los Angeles Times)