Edward Snowden, the 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.

"You in this room, right now have both the means and the capability to improve the future by encoding our rights into programs and protocols by which we rely every day," he told the New York City conference, known as Hackers On Planet Earth, or HOPE.

"That is what a lot of my future work is going to be involved in," he told hundreds of hackers who crowded into an auditorium and overflow rooms to hear him speak from Moscow, where he fled to last year.