An FPGA-based system for tracking digital information transmitted via Peer-to-Peer protocols

At issue for any organization is the illicit dissemination of sensitive information using file sharing applications within a network, and tracking terrorist cells or criminal organizations that are covertly communicating using Voice over IP (VoIP) applications. This paper presents a field programmable gate array (FPGA)-based embedded software tool designed to process file transfers using the BitTorrent peer-to-peer protocol and VoIP phone calls made using the Session Initiation Protocol (SIP). The tool searches a network in real time for selected peer-to-peer control messages using payload analysis and compares the unique identifier of the file being shared or phone number being used against a list of known contraband files or phone numbers. If the identifier is found on the list, the control packet is added to a log file for later forensic analysis. Results show that the FPGA tool processes peer-to-peer packets of interest 92% faster than a software-only configuration and is 99.0% accurate at capturing and processing BitTorrent Handshake messages under a network traffic load of at least 89.6 Mbps. When SIP is added to the system, the probability of intercept for BitTorrent Handshake messages remains at 99.0% and the probability of intercept for SIP control packets is 97.6% under a network traffic load of at least 89.6 Mbps, demonstrating that the tool can be expanded to process additional protocols with minimal impact on overall performance.