| Abstract: | In 2015, Lee proposed time stamp–based and nonce‐based password authenticated key agreement protocols based on the Chebyshev chaotic map to enhance the security of relevant schemes. However, in this paper, we demonstrate that Lee's protocols are vulnerable to user impersonation and stolen verifier attacks. To overcome these security problems, we thus provide an improved version using a smart card. Security analysis and comparisons show that the proposed protocol is more secure and maintains better performance. Furthermore, we perform a formal verification of the proposed protocol using the widely accepted AVISPA tool for error detection. |
