BEIJING (NYTIMES) - A Shanghai police database with a vast trove of personal data that was seized by a hacker or group had been left online, unsecured, for months, security researchers said, in what is probably the largest known breach of Chinese government computer systems. The leak, which came to light after an anonymous user posted in an online forum offering to sell the personal information of as many as 1 billion Chinese citizens, exposes the privacy risks of the Chinese government's vast surveillance and security apparatus. Authorities in China collect vast amounts of data on citizens by tracking their...