By Jim Finkle NEW YORK (Reuters) – Edward Snowden, a former U.S. spy agency contractor who leaked details of major U.S. surveillance programs, called on supporters at a hacking conference to spur development of easy-to-use technologies to subvert government surveillance programs around the globe. Snowden, who addressed conference attendees on Saturday via video link from Moscow, said he intends to devote much of his time to promoting such technologies, including ones that allow people to communicate anonymously and encrypt their messages. He escaped the United States after leaking documents that detailed massive U.S. surveillance programs at home and abroad – revelations that outraged some Americans and sparked protests from countries around the globe. At the HOPE hacking conference, several talks detailed approaches for thwarting government surveillance, including a system known as SecureDrop that is designed to allow people to anonymously leak documents to journalists. The conference featured about 100 presentations on topics ranging from surveillance to hacking elevators and home routers.