According to Cyber Command chief and National Security Agency head Gen. Keith Alexander, cyber attacks are changing and becoming more dangerous.

A CNN article reports that Alexander used his rare public appearance at the American Enterprise Institute in Washington to urge Congress to quickly pass legislation that would give the government additional authorities to communicate what it knows with the private sector to enable a close public-private partnership in terms of cyber security.

Alexander also talked about the economic toll that cyber attacks are taking on the U.S., saying that for every intrusion uncovered by the FBI, 100 go undetected.

He also said that he is concerned about the changing nature of cyber threats from disruptive to destructive attacks, CNN reports, and that the number of cyber attacks against business and infrastructure are on the rise.

However, critics argue that giving the government too much power in cyberspace will come at a cost to civil liberties.

Alexander refused the claims, adding that the government is not interested in reading private email, but is interested in identifying the IP addresses from which malicious computer programs are launched, the article says.

He also mentioned that there are still concerns about terrorist groups such as al Qaeda launching a cyber attack.

Gen. Alexander was also one of Security's Most Influential People in Security in 2011. Who made the list in 2012? Check back with us on August 1 at 9:30 EST to find out!