The U.S. government needs to build trust with private companies so that they will share information about security risks, said Melissa Hathaway, the U.S. National Security Council's cybersecurity chief and author of a recently completed 60-day review of the nation's cybersecurity readiness.

U.S. businesses have a perception that if they share information with the government, it might not stay confidential, said Hathaway, speaking Friday at the Center for Strategic & International Studies (CSIS), a Washington, D.C., think tank.

"We need improved dialogue in the public-private partnership," Hathaway said. "We need to start to build toward trust ... in this area where I think there's not enough trust."

In addition, the U.S. government engages other countries on cybersecurity policy issues in 20 venues, with different agencies engaging in different venues, she said. The U.S. government needs to bring a more united voice to its international work on cybersecurity, she said.

"The federal government can't do [cybersecurity] by itself -- it has to be done with the private sector," Hathaway said. "But we also can't do it in isolation, it's truly an international problem."