A Secure E-Ticketing Scheme for Mobile Devices with Near Field Communication (NFC) That Includes Exculpability and Reusability

An electronic ticket is a contract, in digital format, between the user and the service provider, and reduces both economic costs and time in many services such as air travel industries or public transport. However, the security of the electronic ticket has to be strongly guaranteed, as well as the privacy of their users. We present an electronic ticketing system that considers these security requirements and includes the exculpability as a security requirement for these systems, i.e. users and the service provider can not falsely accuse each other of misbehavior. The system ensures that either both parties receive their desired data from other or neither does (fair exchange). Another interesting property is reusability. Thanks to reusability the tickets can be used a predefined number of times with the same security as single tickets. Furthermore, this scheme takes special care of the computational requirements on the users side by using light-weight cryptography. We show that the scheme is usable in practice by means of its implementation using mobile phones with Near Field Communication (NFC) capabilities.