Java implementation of an authentication protocol with application on mobile phones

Mobile phones are ubiquitous devices that begin to be involved in plenty of tasks in addition to their standard voice function. Using mobile phones to access remote information over TCP/IP is a common demand. However, when travel across networks, information is exposed to several security risks, and the use of cryptographic security unavoidable. Mobile phones still have low computational power and implementing cryptography is not easy as it requires more computational resources. In this paper we deal with the implementation of a broadcast authentication protocol based on quadratic residues chains, constructed with the squaring function, and time synchronization. The advantage of this approach is that the broadcast protocol can run for an unbounded period of time without requiring re-initialization. The protocol is implemented in Java and it is used to authenticate the information received from a remote sender. As the use of the squaring function induces the requirement for more computational power, testing this protocol in a more constrained environment, such as mobile phones, is also relevant in order to establish its performance. The results can be also viewed as the first step to implement an analogous solution to the well known hash chains.