Title: Trusted Sensors Abstract Despite the popularity of adding sensors to mobile devices, the readings provided by these sensors cannot be trusted. Users can fabricate sensor readings with relatively little effort. This lack of trust discourages the emergence of applications where users have an incentive to lie about their sensor readings, such as falsifying a location or altering a photo taken by the camera. This talk presents a trusted sensing architecture that can run on commodity x86 PCs equipped with a Trusted Platform Module (TPM). Unlike previous systems, our archicture does not have to trust the owner of the machine while allowing them to maintain root privileges of the machine, such as performing software updates or even accidentally installing malware. Our system produces signed GPS readings that can attest that the software reading the GPS has not been compromised. In addition to presenting our system's design, we present a software abstraction we found useful in building mobile applications using trusted GPS. This is joint work with He Liu, our summer intern from UC San Diego, and Himanshu Raj and Alec Wolman from Microsoft Research Redmond. Bio Stefan Saroiu is a researcher in the Networking Research Group at Microsoft Research in Redmond. Stefan's research interests span large-scale distributed systems, mobile systems, and computer security. Before coming to MSR in 2008, Stefan spent three years writing papers, teaching, and advising students, which is pretty much what the job of an Assistant Professor at the University of Toronto is. Before that, Stefan spent four months at Amazon.com measuring their workload and participating in the early stages of the design of their new shopping cart service (aka Dynamo). Stefan published papers at NSDI, OSDI, SOSP, MobiSys, Sigcomm, EuroSys, IMC, and coNEXT. Stefan is the author of four award papers, two of which being among the most cited articles in Computer Science published in 2002 and 2003. He has co-chaired two workshops, has served on several program committees, and he is the current information director of the ACM SIGOPS and one of the technical editors of ACM SIGCOMM CCR. Stefan finished his Ph.D. at the University of Washington.