Pakistan, Nov. 1 -- For centuries, the most powerful states protected their greatest secrets behind walls, inside vaults, beneath military installations and in heavily guarded government offices. Strategic plans were locked in steel cupboards. Intelligence reports were marked "Top Secret." Scientific discoveries were restricted to a small circle of officials. Nuclear documents were protected as national treasures. The assumption was that information could remain secret as long as it was physically controlled. That assumption is now being challenged by a technological revolution that may prove more disruptive to national security than many governments are prepared to admit. Artificial intelligence (AI) is transforming the meaning of secrec...