Authentication protocols with nonrepudiation services in personal communication systems

Through the combination of the public-key digital signature and the hash-chaining techniques, a new set of authentication protocols is proposed with the capability of arbitrating disputed bills. These protocols provide security services required by regular authentication protocols and are efficient in consideration of the specific Personal Communication Systems (PCS) environment. They protect subscribers from incorrect service charges and provide service providers legal evidences to collect bills that are denied. They also help identify whether an accounting error, an internal fraud, or a security breach of the service provider causes the incorrect service charge.