Cryptanalysis and improvement of the Lee-Lee identity-based key agreement protocol

Authenticated key agreement protocols are essential for secure communications in open and distributed environments. The protocol design is, however, extremely error-prone due to the inherent complexity of this problem. In this paper, we revisit an efficient identity-based (ID-based) authenticated key agreement protocols due to Lee and Lee. We reveal previously unpublished flaws in the protocol, whereby we demonstrate that it is vulnerable to key control attacks which violate its claimed security attributes. We then put forward an improved protocol to fix the identified security problem.