After an address to the U.S. Chamber of Commerce, Blair also told the crowd he is trying to patch up the relationship between Congress and the intelligence agencies, which was badly strained by a secretive Bush administration and flared up again with revelations this month that the CIA had hidden from the intelligence committees word of a program to develop secret hit teams.
The teams were never operational, according to the CIA. Agency Director Leon Panetta told the House and Senate Intelligence Committees about it June 24, a day after he both learned of the effort and canceled it.
The House Intelligence Committee has launched a full investigation of the program and the CIA's history of congressional notification.
"What I am finding in my six months in the job is that there a lot of legacy issues that we have to work our way through as we establish a relationship with Congress," Blair said. "I have been very clear that we will be on the side of telling them about things."
On the subject of cyberattacks, Blair said the attackers covered their tracks by temporarily hijacking a network of computers, which were used to spawn the cyber offensive. The U.S. is working with other countries to identify the perpetrators.
The South Korean government says it has evidence of North Korean involvement but has not yet assigned blame.
The attacks, in which hundreds of computers tried to connect to a single Web site at the same time to overwhelm the server, caused outages on prominent government-run sites in both the United States and South Korea.
Blair said the attack was relatively unsophisticated.
He said that the Internet in the United States is not as vulnerable to cyberattacks as in some other countries. But he warned that hard work is needed or it could become more vulnerable.
"I don't believe the United States is at risk right now in the way that we have seen countries like Georgia and Estonia," Blair said, referring to two countries temporarily paralyzed by large-scale cyberattacks. "Our infrastructure is too big and too complex and we have practice dealing all the time with a serious number of attacks and other obstacles."
He said the U.S. government quickly spread the word to other agencies about vulnerabilities the July 4 attack exploited so that those holes could be patched. Word of the cyberattacks did not reach the public for several days.
Blair also defended the Obama administration's decision to delay for another six months decisions about what to do with the remaining prisoners at Guantanamo and whether there will be new rules for U.S. interrogators.
"Although no one likes to miss a deadline, looking at it from the inside, it's really a mark of the seriousness with which we are taking it and really taking the time to get the answer right," Blair said.
Asked about his use of private contractors in intelligence work, Blair said about 25 percent of the roughly 100,000 employees in intelligence agencies are private contractors. The use of private contractors to do intelligence work — particularly interrogations in the first few years after the Sept. 11 terrorist attacks — has been questioned on Capitol Hill.
According to the Senate Intelligence Committee's 2010 authorization bill, contract personnel made up 29 percent of the total intelligence workforce in 2008 yet represented 49 percent of the total personnel budget.
"We had more money and missions than we had people to carry them out," Blair said.
Blair said contractors are useful for temporary missions, but inherently governmental duties should remain with federal employees. He said his office is in the process of converting many contract jobs to governmental positions. He did not specify how many.