LEWIS, N.Y. — In a pristine and private corner of the Adirondacks in northern New York, an imposing guardhouse with surveillance cameras discourages the outside world from entering Michael Hopmeier’s property, as does a sign that says: AUTHORIZED PERSONNEL ONLY . Secrecy and privacy are paramount in his line of work, he explained, standing deep inside a decommissioned nuclear missile silo that the military carved into this land at the height of the Cold War. Business requires him to travel the world, but when he is home, he sleeps in the silo’s old control room, attracted to its silence and solitude. An air mattress sits alongside piles of tactical gear. A wall of monitors flicker with footage from a network of security cameras minding the property. A framed blueprint of the silo with an Atlas missile in its chamber leans against a nearby concrete wall. Many of his neighbors here in Lewis, N.Y., know little about Hopmeier’s work or the facility’s history.…