But at the same time, it has allowed the Europeans, the Chinese and other powers to replicate N.S.A. techniques.
France has long been considered one of the most talented powers at stealing industrial secrets and intellectual property, intelligence officials say, although in recent years it has been pushed to the sidelines by the Chinese. Their daily cyberattacks have worked their way into the Pentagon and gotten them the blueprints for the F-35, the most expensive fighter jet in history.
The Russians have a reputation in the intelligence community for taking their time to infiltrate specific communications targets. “They are a lot more patient than the Chinese,” one former American intelligence official said recently, “and so they don’t get caught as often.