Commenting on NSA's "teqniques" of collecting mass amounts of data, he said that they have been ineffective because there arent reliable ways to interpret the material.
The former intelligence contractor added tha his decision to leak documents to journalists "wasn't so I could single handedly change the government; what I wanted to do was inform the public so they could provide their consent to what we should do."
He said that "every society in the world has benefited" from the debate on surveillance.
Documents leaked by Snowden in 2013 revealed widespread surveillance of individuals and institutions in the United States and around the world.
He received temporary asylum in Russia in August.