Yazar "Kim, Minho" seçeneğine göre listele

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    Enhanced Security for the Modified Authenticated Key Agreement Scheme
    (Int Journal Computer Science & Network Security-Ijcsns, 2006) Kim, Minho; Koc, Cetin Kaya
    Hsu 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.
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    Improving the novikov and kiselev user authentication scheme
    (2008) Kim, Minho; Koç, Çetin Kaya
    Novikov and Kiselev [7] proposed an authentication method of a user from a remote autonomous object. Recently, Yang et al. [12] and Awasthi [1] have pointed out that the Novikov-Kiselev scheme is insecure against the man-in-the-middle attack. In this article, we propose an improved version of the Novikov-Kiselev scheme to overcome such vulnerability.
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    A Simple Attack on a Recently Introduced Hash-Based Secure User Authentication Scheme
    (Int Journal Computer Science & Network Security-Ijcsns, 2006) Kim, Minho; Koc, Cetin Kaya
    User authentication is an important service in network security. Recently, several user authentication protocols have been proposed. However, a scheme which withstands all known attacks is not yet available. The Lee-Li-Hwang (LLH) authentication scheme [3] was proposed to circumvent the guessing attack in the Peyravian-Zunic (PZ) password scheme [6]. However, Yoon, Ryu, and Yoo (YRY) [9] discovered that the LLH scheme still suffers from the denial of service attack, and proposed an enhancement for the LLH scheme to solve its security problems. More recently, Ku, Chiang, and Chang (KCC) [2] demonstrated that the YRY scheme is vulnerable to the offline guessing and the stolen-verifier attacks. In this paper, we show that the YRY scheme is also vulnerable to the denial-ofservice attack. Furthermore, it was also claimed in [2] that the YRY scheme cannot achieve backward secrecy. We show in this paper that this claim is not entirely valid.
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    Vulnerabilities in the Adachi-Aoki-Komano-Ohta micropayment scheme
    (2007) Kim, Minho; Koç, Çetin Kaya
    Rivest and Shamir presented two simple micropayment schemes, "PayWord" and "MicroMint," for making small purchases over the Internet [14]. Recently, Adachi et al. have pointed out that the PayWord scheme has two security problems, and proposed a new micropayment scheme to overcome these problems [1]. Nevertheless, we show that their protocol is still vulnerable to impersonation and replay attacks.