Former intelligence contractor Edward Snowden said Monday he has no regrets over his leaks about mass surveillance programs, saying they sparked a needed public debate on spying and data collection.

Snowden, who spoke via video link from Russia to the SXSW festival in Austin, Texas, said he revealed the programs of the US National Security Agency and other such services to foster "a better civic understanding" about what had been secret programs.

He said 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."

Snowden, a former NSA contractor who has been in hiding in Russia and has been charged in the United States with espionage, maintained that "every society in the world has benefited" from the debate on surveillance.

"Regardless of what happens to me, this is something we have a right to know," he said on the link with members of the American Civil Liberties Union, who noted that the hookup was routed through seven proxy servers to keep his location secure.

Snowden, who appeared against a backdrop of a giant copy of the US constitution, said the NSA programs have fundamentally altered the rights outlined in the charter.

"The interpretation of the constitution has been changed from 'no unreasonable searches and seizures,' to 'any seizure is fine, just don't search it,'" he said.

Snowden said he chose to speak to SXSW because he believes it is important to encourage technology companies to make changes to stem mass surveillance.

"The people who are in the room in Austin right now, they are the folks who can really fix things through technical standards," he said.

Snowden said more companies should adopt robust encryption that is built into communications without users having to use complex technical tools.

He maintained that if encryption is too complex, "people aren't going to use it; it has to happen automatically, it has to happen seamlessly."

If online communications are fully encrypted at all stages, Snowden said, bulk data collection would become too difficult for intelligence agencies.

He also said the NSA and other agencies have devoted too many resources to this type of bulk collection and not enough to traditional methods to catch criminals and terrorists.

"We've had tremendous intelligence failures because we are monitoring everybody's communications, instead of suspects," he said.

He cited the Boston marathon bombings as an example, saying "if we hadn't spent so much on mass surveillance, if we followed traditional models, we might have caught" the suspects.

- Congress needs watchdog -

One of the questions came via Twitter from Tim Berners-Lee, creator of the World Wide Web, who thanked Snowden and asked how to make an intelligence oversight system more accountable.

Snowden said "the key factor is accountability" and that Congress needed a watchdog because it failed to adequately oversee the NSA.

"We can't have officials who can lie to the Congress and not face any consequences," he said. "We need a watchdog that watches Congress."

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 -- a move that infuriated the United States and was a key factor behind President Barack Obama's decision to cancel a summit with counterpart Vladimir Putin last year.