National Security Agency whistleblower Edward Snowden appeared via teleconference at SXSW March 10 to discuss national cybersecurity and issues that have been raised in light of his leaking of classified documents relating to mass surveillance of American citizens and people throughout the world.

Snowden, who appeared at the conference from Russia via proxy servers, took a defiant tone in explaining his actions, which he said only occurred because he saw the U.S. Constitution being violated. Snowden alerted numerous superiors at the NSA about his concerns in the months leading up to the leaks, fellow panelist Ben Wizner said.

Snowden and Wizner, director of the American Civil Liberties Union's Speech, Privacy & Technology Project, were also joined by Christopher Soghoian, the ACLU's principal technologist.

At a conference on March 3, Gen. Keith Alexander, director of the NSA, said Snowden's leaks have weakened America's defenses from cyber attacks on Wall Street and other civilian targets.

Snowden said the United States' government has not prioritized cyber defense, choosing instead to focus on offensive operations. This has put civilian targets in danger, he said.

In order to shore up defenses, the United States must focus on strengthening encryption.

"Encryption does work," Snowden said. "We need to not think about encryption as this arcane, dark art. It's something we need to not only be researching, we need to be actively improving. "

Soghoian agreed with Snowden's take. If an individual is being targeted by the NSA, it's "game over," for that individual, he said.

"Encryption makes bulk surveillance too expensive," Soghoian said. "The goal here is not to stop the government from going after legitimate surveillance targets. The goal here is to make it so they cannot spy on innocent people [just] because they can."

Soghoian, Snowden and Wizner also discussed ways to improve oversight of programs like PRISM and agencies like the NSA. Snowden said accountability was the key to keeping agencies like the NSA from violating the constitution. The courts that provide surveillance warrants should be brought into the open, he said.

"A secret court should not be interpreting the constitution," Snowden said. " We need public oversight."

One Twitter user asked Snowden what the average person could do to make their digital experience more secure. Snowden said using certain plug-ins with web browsers can enhance security, and services like TOR, an open source anonymity platform, are useful as well.

Those services work to a certain extent, Soghoian said, but most web browsers cannot do much to withstand attacks from hackers or agencies such as the NSA.

"If you're getting the service for free, the company is not going to be optimizing the experience with your best interest in mind," Soghoian said. "If you want a secure online service, you're going to have to pay for it."