Kim, MinhoKoc, Cetin Kaya2024-10-122024-10-1220061738-7906https://hdl.handle.net/11467/8756Hsu et al. [3] showed that the Ku-Wang [4] modified authentication key agreement scheme is vulnerable to the modification attack and further proposed an improvement of the Ku-Wang scheme. Recently, Lee-Lee [5] showed that the Hsu et al.' s scheme is vulnerable to the modification attack and proposed another improvement on the modified authenticated key agreement scheme. However, we will show that the Hsu et al.' s scheme suffers from the off-line guessing attack and the Lee-Lee's scheme is still vulnerable to off-line guessing, man-inthe - middle, and reflection attacks. We then propose an enhanced secure scheme to eliminate these security flaws.eninfo:eu-repo/semantics/closedAccessKey agreementmodification attackoff-line guessing attackman-in-the-middle attackreflection attackArticle67B164169N/AWOS:000217001800023