WASHINGTON — For decades, leakers of confidential information to the press were a genus that included many species: the government worker infuriated by wrongdoing, the ideologue pushing a particular line, the politico out to savage an opponent. In recent years, technology has helped such leakers operate on a mass scale: Chelsea Manning and the WikiLeaks diplomatic cables, Edward Snowden and the stolen National Security Agency archive, and the still-anonymous source of the Panama Papers.

But now this disparate cast has been joined by a very different sort of large-scale leaker, more stealthy and better funded: the intelligence services of nation states, which hack into troves of documents and then use a proxy to release them. What Russian intelligence did with shocking success to the Democrats in 2016 shows every promise of becoming a common tool of spycraft around the world.

In 2014, North Korea, angry about a movie, hacked Sony and aired thousands of internal emails. Since then, Russia has used the hack-leak method in countries across Europe. The United Arab Emirates and Qatar, Persian Gulf rivals, have accused each other of tit-for-tat hacks, leaks and online sabotage. Other spy services are suspected in additional disclosures, but spies are skilled at hiding their tracks.

“It’s clear that nation states are looking at these mass leaks and seeing how successful they are,” said Matt Tait, a cyber expert at the University of Texas who previously worked at Government Communications Headquarters, the British equivalent of the National Security Agency.