John Walker and the Fleet Broadcasting System
Ph.D. thesis from 2001:
An Analysis of the Systemic Security Weaknesses of the U.S. Navy Fleet Broadcasting System, 1967-1974, as exploited by CWO John Walker, by MAJ Laura J. Heath
Abstract: CWO John Walker led one of the most devastating spy rings ever unmasked in the US. Along with his brother, son, and friend, he compromised US Navy cryptographic systems and classified information from 1967 to 1985. This research focuses on just one of the systems compromised by John Walker himself: the Fleet Broadcasting System (FBS) during the period 1967-1975, which was used to transmit all US Navy operational orders to ships at sea. Why was the communications security (COMSEC) system so completely defenseless against one rogue sailor, acting alone? The evidence shows that FBS was designed in such a way that it was effectively impossible to detect or prevent rogue insiders from compromising the system. Personnel investigations were cursory, frequently delayed, and based more on hunches than hard scientific criteria. Far too many people had access to the keys and sensitive materials, and the auditing methods were incapable, even in theory, of detecting illicit copying of classified materials. Responsibility for the security of the system was distributed between many different organizations, allowing numerous security gaps to develop. This has immediate implications for the design of future classified communications systems.
EDITED TO ADD (9/23): I blogged about this in 2005. Apologies; I forgot.