Undeniable billing in mobile communication

Abstract

In the current mobile communication networks, users have to trust network operators to make correct charges over the calls they made. There is lack of evidence to resolve possible disputes over the number of calls and the duration of each call. Such a concern may grow when users roam among different network operators. This paper proposes an efficient solution to undeniable billing when a mobile user roams into foreign networks. This is achieved by the combination of digital signature and hash-chaining techniques. Mobile users need to submit a digital signature when requesting a call and release chained hash values during the session so that the call and its duration are undeniable. Our mechanism is light-weighted regarding the storage requirement and computation overheads on a mobile user, and is applicable for mobile phone users equipped with a smart card.