"Former NSA spy boss Michael Hayden on Acela behind me blabbing 'on background as a former senior admin official,'" Matzzie wrote. "Sounds defensive."
Matzzie said he heard Hayden use the name "Massimo," leading him to believe the former official was speaking to Time's national security reporter, Massimo Calabresi, The Washington Post reported.
Hayden said Matzzie mischaracterized his conversation.
"I didn't criticize the president," Hayden told the Post. "I actually said these are very difficult issues. I said I had political guidance, too, that limited the things that I did when I was director of NSA. Now that political guidance [for current officials] is going to be more robust. It wasn't a criticism."
Matzzie said Hayden was apparently tipped off to his tweets at some point during the train ride, because he came over and offered a "real interview." The two men said they talked about subjects including the Fourth Amendment and NSA spying before agreeing to disagree.