WASHINGTON (AP) — Even in an era when former officials routinely profit from business ventures linked to their public service, recently retired National Security Agency chief Keith Alexander raised eyebrows when he disclosed he is working on patents for what he calls a game-changing cybersecurity model.

Alexander had access to the nation’s deepest secrets about cyberwarfare, and he spent the last several years warning about cyberthreats to private industry. Critics questioned whether he was cashing in on classified information he learned at NSA, and they asked why he didn’t deploy his new ideas while he led the government’s cyber defenses.