Many people desire ubiquitous access to their personal computing environments. We present a system in which a user leverages a personal mobile device to establish trust in a public computing device, or kiosk, prior to resuming her environment on the kiosk. We have designed a protocol by which the mobile device determines the identity and integrity of all software loaded on the kiosk, in order to inform the user whether the kiosk is trustworthy. Our system exploits emerging hardware security technologies, namely the Trusted Platform Module and new support in x86 processors for establishing a dynamic root of trust. We have demonstrated the viability of our approach by implementing and evaluating our system on commodity hardware. Through a brief survey, we found that respondents are generally willing to endure a delay in exchange for an increased assurance of data privacy, and that the delay incurred by our unoptimized prototype is close to the range tolerable to the respondents. We have...