Applicability of Host Identities to Implement Non-Repudiable Service Usage

In a typical roaming scenario the accounting information received from the roaming partner is expected to be trustworthy. Things like fear of losing one's reputation have been working as disincentives for fraudulent behaviour between the large operators. However, when smaller players enter the market and steps are taken towards more dynamic relationships as in the visions of ubiquitous computing environments, the need for reliable records becomes paramount. Thus, secure accounting mechanisms are needed for ensuring correct compensation amongst the interoperating partners. On top of that, the partners need to be authorised with sufficient granularity to be able to engage in the transaction in the first place. The mere authentication should not be enough. In this article we present a solution concept for ensuring non-repudiation of the service usage, so that cryptographically secure accounting records can be generated, and the parties involved in the transaction make their commitments only to the resources actually consumed. The solution is based on the employment of Host Identity Protocol (HIP) and hash chains, so that we can provide a convenient binding between the identity and authorisation information. Also, in order to avoid service hijacking, mechanisms for binding this information to the actual traffic are discussed