The crackdown has been in response to pressure from intelligence agencies and members of Congress to get tougher with unauthorized disclosures, but press advocates and journalists have complained that it has discouraged officials from talking about security matters.

Mr. Kiriakou worked from 1990 to 2004 as a C.I.A. analyst and a counterterrorism officer, including in Pakistan after the Sept. 11, 2001, terrorist attacks. He helped lead the operation that captured Abu Zubaydah, who helped run a training camp for Al Qaeda fighters and other militants, and whose detention after a shootout in Pakistan was hailed as the agency’s first big success after Sept. 11. Mr. Kiriakou described the episode in a 2012 memoir, “The Reluctant Spy: My Secret Life in the C.I.A.’s War on Terror.”

He was charged in 2012 with disclosing classified information to journalists, including this reporter. Later that year, in a plea deal, he admitted to one of the leaks, saying he had disclosed the name of an undercover C.I.A. officer to a freelance journalist, Matthew Cole, though Mr. Cole did not publish the name. Mr. Kiriakou was sentenced to 30 months in prison and sent to a low-security prison in Loretto, Pa. Judge Leonie M. Brinkema of Federal District Court in Alexandria, Va., who presided over the case, said at the time that she would honor the plea agreement but thought that the sentence was “way too light.”

In 2007, in an interview with ABC News, Mr. Kiriakou became the first former C.I.A. official to publicly discuss the agency’s use of waterboarding, a suffocation technique with a prominent place in the history of torture. He later said that he intended to defend colleagues who had used extreme measures in the anxious aftermath of Sept. 11, and he inaccurately claimed that Abu Zubaydah had opened up after mere seconds of waterboarding; documents later showed he had been subjected to the treatment 83 times. But Mr. Kiriakou told ABC that he had come to believe that waterboarding was wrong.

The leak case against him did not mention his ABC interview, and prosecutors insisted that it played no role in their decision to charge him. But like several others charged with leaking since 2009, Mr. Kiriakou has been embraced as a whistle-blower by civil liberty advocates and government critics who say he was punished for speaking out about C.I.A. torture.