Password-based key retrieval protocol for roaming systems

In this paper, a new password-based key retrieval protocol for roaming systems is presented. A roaming user can download his secret key from a group of servers only with his identity and a simple password by this protocol. Different from previous protocols, the presented protocol is very efficient not only when servers are well but also when some servers are compromised. In addition, because a new technique is adopted, the presented protocol has a unique attribute, that is, it can detect the bad servers during execution. It is especially useful where the servers are easy to be compromised. Finally, we give the full performance and security analysis.