China Daily reports on transportation cards in China and how they could be used to track people:
When you use yikatong, the blue cards passengers often swipe when boarding a public bus or subway train, a person can learn exactly when you rode public transport and where you went simply by typing onto a website the 17 numbers appearing on the card.
Li Tiejun, an engineer at the Beijing office of Kingsoft, a Zhuhai-based software company, wrote about the card “secret” on his micro blog after discovering on Sunday that he could use the Beijing Municipal Administration and Communication Card Co’s official website to obtain information about his previous whereabouts. He did not even have to bother with typing in a password to get it. […]
He compared the company’s website to a big database without a lock.
Within 20 hours, Li’s complaints had been forwarded more than 3,000 times, provoking a controversy online about whether putting such information out to the public violates cardholders’ privacy. […]
More than 45 million yikatong cards are now in use in Beijing. By swiping them in front of a sensor, passengers can enjoy a 60 percent discount on public bus fares. The cards can also be used at designated supermarkets, on long-distance bus lines, on expressway tollgates in Beijing and in public telephones on the capital’s streets.
Chengdu residents, meanwhile, have found that the local public transport operator’s website contains similar information about them. In Shanghai, though, the public can only learn the amount of credit left on a yikatong card.