文档介绍：S-SPAN: Secure Smart Posters in Android using NFC Jason Wu, Lin Qi, Nishant Kumar, Ram Shankar Siva Kumar, and Patrick Tague Carnegie Mellon University, Electrical puter Engineering {jasonwu, linq, nkumar1, ramshans, tague}***@ Abstract—Smart posters are a promising new use case for NFC-enabled mobile devices, but to date there has been a general lack of security mechanisms for NFC smart posters. We present S-SPAN - a secure smart poster system consisting of three parts: an administrative web interface for managing posters, a backend server for storing and serving data, as well as an Android applica- tion for end-users. S-SPAN enforces con?dentiality and integrity of smart poster data as well as authentication/authorization of administrators and end-users, thus ensuring that only authorized users can access the content. I. I NTRODUCTION Smart posters, which allowbusinesses or anizations to disseminate information to end-users in a more interactive fashion than standard posters, are an increasingly popular application of NFC tags. Such tags store small amounts of read-only (or monly, rewriteable) data. A typical use case for NFC smart posters is to provide users of NFC- enabled smartphones with quick access to a URL related to the poster content; for example, a user interested in a product advertisement might swipe her phone over the ad poster to open a webpage containing detailed speci?cations and a link to purchase the item. There are also situations that call for smart posters to contain sensitive information only privy to speci?c users. For example, a museum may wish to use NFC smart posters in tandem with a custom smartphone application, to provide additional information about exhibits on the condition that the content should only be available to users who have paid for admission on a given day. S-SPAN aims to provide a framework for secure active-passive pairings between NFC tags and Android devices in a smart poster setting. This project was motiva