Trust Negotiation and Its Applications

Trust negotiation is an approach for establishing trust between various entities that is especially useful in online environments. Entities may need to or want to establish a trust relationship in order to reach their goal, on which they can collaborate together. Its principle is to mutually and alternately exchange credentials between the participating entities so that their trust placed onto each other can gradually increase. Trust negotiation must also handle other issues that are important for its functionality. The first and the most important one is security. Entities must be securely authenticated in order to know who they communicate with. Also, they must be authorised for accessing confidential information about the other one, which is handled by specific rules defined in policies. Credentials themselves must be protected too in order to maintain their integrity and prevent malicious modifications and leakage. Privacy is another related issue. It is not always indispensable to protect privacy in order to establish trust, however, entities may be willing to do so. Trust negotiation may be required for many different scenarios and its processing can be carried out automatically without an active intervention from its participants. In this chapter, we analyse trust negotiation in terms of its functionality and possible implementations. We propose a way of how to design trust negotiation effectively for several scenarios since each of them may have different requirements for trust negotiation, such as the needs for security and privacy, the use of various negotiating strategies or the use of trusted authorities. We propose the way of how trust negotiation can be adapted for the specific needs required by its participants.