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Cracking China's Skype Surveillance Software

A 27-year-old unlocked a secret word list employed to monitor Chinese Skype users
Jeffrey Knockel
Jeffrey KnockelPhotograph by Benjamin Rasmussen for Bloomberg Businessweek

Jeffrey Knockel is an unlikely candidate to expose Skype’s role in China’s online surveillance apparatus. The 27-year-old computer science graduate student at the University of New Mexico in Albuquerque doesn’t speak Chinese, let alone follow Chinese politics. “I don’t really keep up with news in China that much,” he says. What gets him going are puzzles.

So when a professor pulled Knockel aside after class two years ago and suggested a long-shot project—to figure out how the Chinese version of Microsoft’s Skype secretly monitors users—he hunkered down in his bedroom with his Dell laptop. Other academics have known since 2008 that Skype tracks politically sensitive text messages on its Chinese videophone and texting service, known as TOM-Skype, a joint venture formed in 2005 with majority owner TOM Online, a Chinese wireless Internet company. Knockel, a bearded, yoga-practicing son of a retired U.S. Air Force officer, cracked the encryption cloaking Skype’s Chinese service and for the first time identified the thousands of terms—such as “Amnesty International” and “Tiananmen”—that prompt Skype in China to intercept typed messages and send copies to its computer servers in the country. Some messages are blocked altogether.