China obtained secret stealth technology used on B-2 bomber engines from a Hawaii-based spy ring in a compromise U.S. officials say will allow Beijing to copy or counter a key weapon in the Pentagon's new strategy against China. Details of the classified defense technology related to the B-2's engine exhaust system and its ability to avoid detection by infrared sensors were sold to Chinese officials by former defense contractor Noshir S. Gowadia, an Indian-born citizen charged with spying in a federal indictment released by prosecutors in Hawaii.