Security of NFC applications

Abstract: Near Field Communication (NFC) refers to a communication technology that enables an effortless connection and data transfers between two devices by putting them in a close proximity. Besides contactless payment and ticketing applications, which were the original key drivers of this technology, a large number of novel use cases can benefit from this rapidly developing technology, as has been illustrated in various NFC-enabled application proposals and pilot trials. Typical NFC-enabled systems combine NFC tags, NFC-enabled mobile phones, and online servers. This thesis explores the trust relationships, security requirements, and security protocol design in these complex systems. We study how to apply the security features of different types of NFC tags to secure NFC applications. We first examine potential weaknesses and problems in some novel use cases where NFC can be employed. Thereafter, we analyze the requirements and propose our system design to secure each use case. In addition, we developed proof-of-concept implementations for two of our proposed protocols: an NFCenabled security-guard monitoring system and an NFC-enabled restaurant menu. For the former use case, we also formally verified our proposed security protocol.  Our analysis shows that among the discussed tags, the NFC tags based on secure memory cards have the least capability and flexibility. Their built-in three-pass mutual authentication can be used to prove the freshness of the event when the tag is tapped. The programmable contactless smart cards are more flexible because they can be programmed to implement new security protocols. In addition, they are able to keep track of a sequence number and can be used in systems that do not require application-specific software on the mobile phone. The sequence number enforces the order of events, thus providing a certain level of replay prevention. The most powerful type of tag is the emulated card since it provides a clock, greater computational capacity, and possibly its own Internet connection, naturally at higher cost of deployment.