At the Spring 1967 Joint Computer Conference, many leading computer specialists again met to discuss system security concerns. During this conference, the computer security experts Willis Ware, Harold Petersen, and Rein Turn, all of the RAND Corporation, and Bernard Peters of the National Security Agency (NSA), all used the phrase "penetration" to describe an attack against a computer system. In a paper, Ware referred to the military's remotely accessible time-sharing systems, warning that "Deliberate attempts to penetrate such computer systems must be anticipated." His colleagues Petersen and Turn shared the same concerns, observing that online communication systems "...are vulnerable to threats to privacy," including "deliberate penetration." Bernard Peters of the NSA made the same point, insisting that computer input and output "...could provide large amounts of information to a penetrating program." During the conference, computer penetration would become formally identified as a major threat to online computer systems.