As Iran braced for conflict with the U.S., a key regime financier built a secret payment network to keep money flowing to its military forces. At its core was Binance. Until as recently as December, the network, run by Babak Zanjani, an Iranian who is a self-described “antisanction” operator, made $850 million in transactions over two years on the world’s largest cryptocurrency exchange, mostly on a single trading account, internal Binance compliance reports show. Zanjani allies, including a sister, a romantic partner and a director of Zanjani’s company, ran additional accounts, all accessed from the same devices—a pattern the Binance investigators…