SKYNET is a program by the U.S. National Security Agency that performs machine learning analysis on communications data to extract information about possible terror suspects. The tool is used to identify targets, such as al-Qaeda couriers, who move between GSM cellular networks. Specifically, mobile usage patterns such as swapping SIM cards within phones that have the same ESN, MEID or IMEI number are deemed indicative of covert activities. Like many other security programs, the SKYNET program uses graphs that consist of a set of nodes and edges to visually represent social networks. The tool also uses classification techniques like random forest analysis. Because the data set includes a very large proportion of true negatives and a small training set, there is a risk of overfitting. Bruce