Admiral Rogers discussed his vision of how the United States might use cyberweapons against adversaries — a subject of debate inside the administration that American officials rarely discuss in public — saying he could imagine a day when, under strict rules of armed conflict, they were used selectively but as part of ordinary military operations, like cruise missiles and drones.

He also acknowledged that the quiet working relationships between the security agency and the nation’s telecommunications and high technology firms had been sharply changed by the Snowden disclosures — and might never return to what they once were in an era when the relationships were enveloped in secrecy.

Telecommunications businesses like AT&T and Verizon, and social media companies, now insist that “you are going to have to compel us,” Admiral Rogers said, to turn over data so that they can demonstrate to foreign customers that they do not voluntarily cooperate. And some are far more reluctant to help when asked to provide information about foreigners who are communicating on their networks abroad. It is a gray area in the law in which American courts have no jurisdiction; instead, the agency relied on the cooperation of American-based companies.

Last week, Verizon lost a longstanding contract to run many of the telecommunications services for the German government. Germany declared that the revelations of “ties revealed between foreign intelligence agencies and firms” showed that it needed to rely on domestic providers.

Google has announced steps to seal gaps in its system that the security agency exploited to gain access to the company’s databases. Microsoft is challenging in court the validity of warrants to turn over data that it stores outside the United States.

“I understand why we are where we are,” said Admiral Rogers, the first career cryptologist to run the country’s code-breaking and code-making agency, and a former commander of the Navy’s Fleet Cyber Command. “I don’t waste a lot of time saying, ‘Why wouldn’t you want to work with us?’ ”

Admiral Rogers said the majority of corporations that had long given the agency its technological edge and global reach were still working with it, though they had no interest in advertising the fact. He was unapologetic about the agency’s past activities, even as he said he recognized that unlike his predecessors for the past six decades he was going to have to engage “in a public dialogue” about how the agency operated.