HE MESSAGE ARRIVED AT NIGHT AND CONSISTED OF THREE WORDS: "GOOD EVENING SIR!"

The sender was a hacker who had written a series of provocative memos at the National Security Agency. His secret memos had explained — with an earthy use of slang and emojis that was unusual for an operative of the largest eavesdropping organization in the world — how the NSA breaks into the digital accounts of people who manage computer networks, and how it tries to unmask people who use Tor to browse the web anonymously. Outlining some of the NSA's most sensitive activities, the memos were leaked by Edward Snowden, and I had written about a few of them for The Intercept.

There is no Miss Manners for exchanging pleasantries with a man the government has trained to be the digital equivalent of a Navy SEAL. Though I had initiated the contact, I was wary of how he might respond. The hacker had publicly expressed a visceral dislike for Snowden and had accused The Intercept of jeopardizing lives by publishing classified information. One of his memos outlined the ways the NSA reroutes (or "shapes") the internet traffic of entire countries, and another memo was titled "I Hunt Sysadmins." I felt sure he could hack anyone's computer, including mine.