HyCPK: Securing Identity Authentication in ubiquitous computing

Identity authentication (IA) is vital in ubiquitous computing systems, one of which is web service system; however most current IA schemes and technologies are facing various kinds of attacks and large-scale certification problem. To address this problem, this paper proposes the HyCPK, an improved CPK algorithm based on a single-double hybrid matrix. In this algorithm, the key management center produces a basic key matrix and an assistant key matrix simultaneously, and the former is used to calculate the keys of web services, while both are used to calculate the keys of users. Moreover, CPK identity is redefined to be composed of user identity and the corresponding validity date, which enables the validation processes to be tackled in a more convenient way. Contrasting with the existing CPK schema, the proposed algorithm can solve the problem of large-scale certification and resist three main collusion attacks, and hence the security performance is improved.