Birnstill, PascalPascalBirnstillBier, ChristophChristophBierWagner, P.P.WagnerBeyerer, JürgenJürgenBeyerer2022-03-052022-03-052018https://publica.fraunhofer.de/handle/publica/25003210.1007/978-3-319-58424-9_25Data usually takes different shapes and appears as files, windows, processes' memory, network connections, etc. Information flow tracking technology keeps an eye on these different representations of a data item. Integrated with a usage control (UC) infrastructure, this allows us to enforce UC requirements on each representation of a protected data item. To enable UC enforcement in distributed settings, we need to be able to track information flows across system boundaries. In this paper, we introduce a state-based information flow model for tracking explicit flows between systems equipped with UC technology. We demonstrate the applicability of our approach by means of an instantiation in the field of video surveillance, where systems are increasingly accessed via insecure mobile applications. Based on usage control and inter-system information flow tracking, we show how video data transmitted from a video surveillance server to mobile clients can be protected against illegitimate duplication and redistribution after receipt.en004670book article