GUY RAZ, Host: From NPR News, this is ALL THINGS CONSIDERED. I'm Guy Raz.</s>ROBERT SIEGEL, Host: As NPR's Martin Kaste reports, the network's security is only as reliable as the people using it.</s>MARTIN KASTE: Kiki Munshi is a retired foreign service officer who served a couple of years in Iraq. She recalls having two computers on her desk.</s>KIKI MUNSHI: One that I used for everyday conversation and one which was a military computer and could be used for classified information.</s>MARTIN KASTE: That second military computer would've been connected to SIPRNET. It was meant for secret communications, but technically, it was nothing fancy. Bruce Schneier is a prominent author and consultant on computer security.</s>BRUCE SCHNEIER: What the government did is they made their own network. It looks just like the Internet, except it's for classified information, and only people who are cleared had access to it.</s>MARTIN KASTE: The network was expanded intentionally after 9/11 because of the belief that more information sharing between agencies might lead to the detection of terror plots. But SIPRNET has expanded so much, an estimated two million or more military and civilian personnel now have access to the system. With that many users, no amount of special logins or tracking software can guarantee security, says Schneier.</s>BRUCE SCHNEIER: The more people have access to it, the more people can decide deliberately to leak it or accidentally to leak it.</s>MARTIN KASTE: Martin Kaste, NPR News.
It is believed that the leaked diplomatic cables came from the Secret Internet Protocol Router Network — or SIPRNET. That's the secure "private Internet" used by the military and the State Department. But the network's security is only as reliable as the people using it.