As a result, the strategy goes beyond the rules of managing cyberconflict and focuses on American efforts to assure control over physical technologies like undersea cables, which connect countries, companies and individual users to cloud services.

Huawei, the Chinese telecommunications giant, has been seeking to dominate the laying of cables across the Pacific and, increasingly, around the world. But Mr. Fick maintains that American, Japanese and European firms still dominate the market, and that “this remains one area where we can compete vigorously.”

Mr. Blinken, in his speech, made clear that part of the diplomacy he envisions involves persuading nations not to rely on undersea cables, data storage or cloud computing supplies from Chinese suppliers, or other states in China’s technological orbit. He describes an increasingly zero-sum competition, in which countries will be forced to choose between signing up for a Western-dominated “stack” of technologies or a Chinese-dominated one.

“In these arenas, the United States currently leads the world, but providers from authoritarian states are increasingly competitive,” Mr. Blinken told the RSA Conference. “It’s critical we work with trusted vendors and exclude untrustworthy ones from the ecosystem.”

Mr. Blinken made clear, by implication, that it was China’s firms he was labeling as untrustworthy.

He cited a U.S.-backed effort, along with Australia, Japan, New Zealand and Taiwan, to link up 100,000 people living in the Pacific islands — a tiny population, but one that China has targeted because of its strategic location — in its effort to expand its influence in the South Pacific.