Edward Snowden told the audience of a technology conference this week that while encryption is a "defense against the dark arts in the digital realm" it needs improvement.

Snowden, best known for releasing secret U.S. government files to various media outlets last year, made the comments earlier this week via web video during question and answer session at the South by Southwest Interactive conference in Austin, Texas, according to the Wall Street Journal.

Behind Snowden was an image of an enlarged copy of the U.S. Constitution.

Snowden, a former National Security Administration contractor who leaked classified documents detailing NSA surveillance programs, answered queries as part of a panel hosted by the American Civil Liberties Union.

He said that encryption does work and that the federal government still does not have an idea which documents he took because of that.

Snowden was linked digitally to the panel through seven proxies according to a panel speaker.

Snowden also called for academia to bolster methods of encryption after reports that algorithms which generate random numbers are being compromised.

Hosting the panel was the director of the ACLU's Speech, Privacy & Technology project Ben Wizner, who also serves a legal advisor for Snowden. Christopher Soghoian, the ACLU's principal technologist was also part of the panel.

With regard to the allegations of the NSA having undue influences on the standard for encryption algorithm, publication Dark Reading noted that Soghoian said that the news of the NSA "allegedly subverting random number generation algorithm has "radicalized" some member [sic] of the encryption community who 'feel they were lied to' and can make changes to improve encryption."

Snowden urged tech firms to make their encryption systems better in order to protect their users from government surveillance. He said the tech firms can act faster than the government, as the latter moves too slowly in altering intelligence-gathering practices.