Snowden, who appeared via video link at Toronto's Roy Thomson Hall during a semi-annual Munk debate that state surveillance today is a euphemism for mass surveillance.

"It's no longer based on the traditional practice of targeted taps based on some individual suspicion of wrongdoing," Snowden said in the brief video. "It covers phone calls, emails, texts, search history, what you buy, who your friends are, where you go, who you love."

The video was screened as two of the debaters — former U.S. National Security Administration director General Michael Hayden and well-known civil liberties lawyer and Harvard law professor Alan M. Dershowitz — argued in favor of the debate statement: "Be it resolved state surveillance is a legitimate defense of our freedoms."