How much data regarding U.S. anti- and counterterrorism systems, countermeasures, and defenses is publicly available and how easily could it be found by individuals seeking to harm U.S. domestic interests? The authors developed a framework to guide assessments of the availability of such information for planning attacks on the U.S. air, rail, and sea transportation infrastructure, and applied the framework in an information-gathering exercise that used several attack scenarios. Overall, the framework was useful for assessing what kind of information would be easy or hard for potential attacker |