In early January 1955, an NSA employee pleaded guilty to an espionage-related offense, the first ever. This led to the first public mentions of NSA, which was only little more than two years old.

During World War II, Joseph Petersen had been assigned to cryptanalytic work In the South Pacific, and had worked with some Dutch cryptanalysts m a cooperative effort against Japanese communications.  He apparently formed a close friendship with one of them.

The friendship remained close after the war, and Petersen continued, illegally, to send his friend classified documents about cryptologic activities.

In 1953, when, Incidental to an investigation of a U.S. Navy officer, security officials learned that Petersen had close contacts at the Dutch embassy, they contacted the FBI. Petersen revealed some of his activities under questioning, and the FBI found classified documents in his apartment.

The decision on whether to prosecute was left to General Ralph Canine, director of NSA. Although he was advised to do nothing more than fire Petersen, since a trial might result m the release of secrets, Canine chose to prosecute.

However, the case did not go to trial. Petersen decided to plead guilty. In light of his cooperation with the FBI, Petersen was sentenced to only seven years. He was released after four.

Even without a trial, the case was public knowledge. The Associated Press Circulated an article about Petersen, describing NSA as an agency that “listens in on the world’s radio traffic, both conventional messages and coded material.” The news service went on to say that NSA had tighter secrecy than the CIA, and it was “not listed by name either in the Washington directory or in the Pentagon phone directory.”

This, incidentally, may be the origin of the canard that NSA was at one time a secret organization.

Source: NSA