• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.1
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• pp.3-10
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• 2008

Since a number of password-based protocols are using human memorable passwords they are vulnerable to several kinds of password guessing attacks. In this paper, we show that two password-based key exchange and authentication protocols are insecure against off-line password-guessing attacks.

• Journal of the Korea Society of Computer and Information
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• v.15 no.2
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• pp.119-125
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• 2010

Recently Hsiang-Shih proposed the user authentication scheme to improve Yoon et al's scheme. But the proposed scheme has not been satisfied security requirements considering in the user authentication scheme using the password based smart card. In this paper, we proved that Hsiang-Shih's scheme is vulnerable to the off-line password guessing attack. In other words, the attacker can get the user's password using the off-line password guessing attack on the scheme when the attacker steals the user's smart card and extracts the information in the smart card. Also, the improved scheme based on the hash function and random number was introduced, thus preventing the attacks, such as password guessing attack, forgery attack and impersonation attack etc. And we suggested the effective mutual authentication scheme that can authenticate each other at the same time between the user and server.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.12
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• pp.6188-6204
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• 2017

Over the years, more password-based authentication key agreement schemes using chaotic maps were susceptible to attack by off-line password guess attack. This work approaches this problem by a new method--new theorem of chaotic maps: $T_{a+b}(X)+T_{a-b}(X)=2T_a(X)T_b(X)$,(a>b). In fact, this method can be used to design two-party, three-party, even in N-party intelligently. For the sake of brevity and readability, only a two-party instance: a novel Two-party Password-Authenticated Key Agreement Protocol is proposed for resisting password guess attack in this work. Compared with the related literatures recently, our proposed scheme can be not only own high efficiency and unique functionality, but is also robust to various attacks and achieves perfect forward secrecy. For capturing improved ratio of security and efficiency intuitively, the paper firstly proposes a new parameter called security/efficiency ratio(S/E Ratio). The higher the value of the S/E Ratio, the better it is. Finally, we give the security proof and the efficiency analysis of our proposed scheme.

• Journal of the Korea Society of Computer and Information
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• v.16 no.2
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• pp.173-181
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• 2011

User authentication and key exchange protocols are the most important cryptographic applications. For user authentication, most protocols are based on the users' secret passwords. However, protocols based on the users' secret passwords are vulnerable to the password guessing attack. In 1992, Bellovin and Merritt proposed an EKE(Encrypted Key Exchange) protocol for user authentication and key exchage that is secure against password guessing attack. After that, many enhanced and secure EKE protocols are proposed so far. In 2006, Lo pointed out that Yeh et al.'s password-based authenticated key exchange protocol has a security weakness and proposed an improved protocol. However, Cao and Lin showed that his protocol is also vulnerable to off-line password guessing attack. In this paper, we show his protocol is vulnerable to on-line password guessing attack using new attack method, and propose an improvement of password authenticated key exchange protocol for imbalanced wireless networks secure against password guessing attack.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.163-165
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• 2008

Recently, Lu and Cao proposed a password-authenticated key exchange protocol in the three party setting, and the authors claimed that their protocol works within three rounds. In this paper, we analyze the protocol and show the protocol cannot work within three rounds. We also find two security flaws in the protocol. The protocol is vulnerable to an undetectable password guessing attack and an off-line password guessing attack.

• Convergence Security Journal
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• v.22 no.4
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• pp.179-188
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• 2022

Password authentication schemes (PAS) are the most common mechanisms used to ensure secure communication in open networks. Mathematical-based cryptographic authentication schemes such as factorization and discrete logarithms have been proposed and provided strong security features, but they have the disadvantage of high computational and message transmission costs required to construct passwords. Fairuz et al. therefore argued for an improved cryptographic authentication scheme based on two difficult fixed issues related to session key consent using the smart card scheme. However, in this paper, we have made clear through security analysis that Fairuz et al.'s protocol has security holes for Privileged Insider Attack, Lack of Perfect Forward Secrecy, Lack of User Anonymity, DoS Attack, Off-line Password Guessing Attack.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.5
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• pp.131-137
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• 2011

Recently Lin et al. proposed a simple remote user authentication scheme using smart cards. But the proposed scheme has not satisfied security requirements which should be considered in the user authentication scheme using the password based smart card. In this paper, we show that Lin et al.'s scheme is insecure against off-line password guessing attack. In their scheme, any legal user's password may be derived from the password guessing when his/her smart card is stolen and the secret information is leaked from the smart card by an attacker. Accordingly, we demonstrate the vulnerability of their scheme and present an enhancement to resolve such security weakness. Our proposed scheme can withstand various possible attacks including password guessing attack. Furthermore, this improved scheme can provide mutual authentication to improve the security robustness. Performance evaluation shows that the proposed scheme is relatively more effective than Lin et al.'s scheme.

• Journal of Korea Multimedia Society
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• v.11 no.10
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• pp.1403-1408
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• 2008

A number of three party key exchange protocols using smart card in effort to reduce server side workload and two party password based key exchange authentication protocols has been proposed. In this paper, we introduce the survey and analysis on security vulnerability of smart card based three party authenticated key exchange protocols. Furthermore, we analyze Kwak et al's password based key exchange and authentication protocols which have shown security weakness such as Shim et al's off-line password guessing attack and propose the countermeasure to deter such attack.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.6
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• pp.303-310
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• 2011

Recently, many user authentication schemes using smart cards have been proposed to improve the security weaknesses in user authentication process. In 2009, Wang et al. proposed a more effective and secure dynamic ID-based remote user authentication scheme to improve the security weakness of Das et al.'s scheme, and asserted that the improved scheme is secure against independent of password in authentication phase and provides mutual authentication between the user and the remote server. However, in this paper, we analyze the security of Wang et al. scheme and demonstrate that Wang et al.'s scheme is vulnerable to the man-in-the-middle attack and the off-line password guessing attack. In addition, we show that Wang et al. scheme also fails to provide mutual authentication. Accordingly, we propose an improved scheme to overcome these security weakness even if the secrete information stored in the smart card is revealed. Our proposed scheme can withstand the user impersonation attack, the server masquerading attack and off-line password guessing attack. Furthermore, this improved scheme provides the mutual authentication and is more effective than Wang et al.'s scheme in term of the computational complexities.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.9B
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• pp.931-938
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• 2009

Recently, Holbl et al. proposed an improvement to Peyravian-Jeffries's password-based authentication protocol to overcome some security flaws. However, Munilla et al. showed that Holbl et al.'s improvement is still vulnerable to off-line password guessing attack. In this paper, we provide a secure password-based authentication protocol which gets rid of the security flaws of Holbl et al.'s protocol.