New York financial regulators are considering tougher cyber security requirements for banks to mandate more complex computer sign-ins and certifications from the contractors of their cyber defenses, the state’s top regulator said Wednesday. They are already revamping regular examinations of banks and insurance companies by adding targeted assessments of barriers against hackers, Department of Financial Services Superintendent Ben Lawsky said. He’s “deeply worried” that within the next decade, or sooner, there will be “a major cyber attack aimed at the financial system” that could create a run or panic that spills over into the broader economy, he said. “At DFS, we believe that cyber security is likely the most important issue we will face in 2015 and perhaps for many years to come after that,” Lawsky said in an address at Columbia Law School. Internet architecture has grown up with usernames and passwords to verify identities, but all firms now should now be moving toward “a multi-factor authentication system” with an additional layer of security, he said.