• The KIPS Transactions:PartC
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• v.11C no.4
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• pp.439-446
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• 2004

In the Internet, user authentication is the most important service in secure communications. Although password-based mechanism is the most widely used method of the user authentication in the network, people are used to choose easy-to-remember passwords, and thus suffers from some Innate weaknesses. Therefore, using a memorable password it vulnerable to the dictionary attacks. The techniques used to prevent dictionary attacks bring about a heavy computational workload. In this paper, we describe a recent solution, the Optimal Strong-Password Authentication (OSPA) protocol, and that it is vulnerable to the stolen-verifier attack and an impersonation attack. Then, we propose an Improved Optimal Strong-Password Authentication (I-OSPA) protocol, which is secure against stolen-verifier attack and impersonation attack. Also, since the cryptographic operations are computed by the processor in the smart card, the proposed I-OSPA needs relatively low computational workload and communicational workload for user.

• Journal of Digital Convergence
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• v.14 no.10
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• pp.287-293
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• 2016

Wireless sensor networks (WSNs) have many applications and are deployed in a wide variety of areas. They are often deployed in potentially adverse or even hostile environment so that there are concerns on security issues in these WSNs. Recently, an anonymous user authentication and key agreement scheme (AUAKAS) was proposed based on symmetric cryptosystem in WSNs. It is claimed in AUAKAS that it assures security against different types of attacks including impersonation attacks. However, this paper shows that AUAKAS does not cope from user impersonation attack and gateway impersonation attack from the legally registered user on the gateway. The security analysis could guide the required features of the security scheme to be satisfied.

• The Journal of the Korea Contents Association
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• v.13 no.4
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• pp.17-22
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• 2013

Impersonation attack, based on vulnerable security of SIP, facilitate a intruder to take malicious actions such as toll fraud and session hijacking. This paper suggests a new technique for a countermeasure. When receiving a register request message, registrar checks whether the value of Form header or the value of Call-ID header is stored in location server or not. If the record containing either of them are stored and periodically updated, we regard that message as impersonation attack and discard it. Since this technique uses the information stored in server instead of adding encryption mechanism for user authentication, it can easily build securer SIP environment.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.4
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• pp.89-108
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• 2010

Recently many mutual authentication protocol for light-weight hash-based for RFID have been proposed. Most of them have assumed that communications between a backend server and reader are secure, and not considered threats for backend server and RFID reader impersonation. In the real world, however, attacks against database or reader are more effective rather than attacks against RFID tag, at least from attacker's perspective. In this paper, we assume that all communications are not secure to attackers except the physical attack, and considering realistic threats for designing a mutual authentication protocol based on hash function. And It supports a mutual authentication and can protect against the replay attack, impersonation attack, location tracking attack, and denial of service attack in the related work. We besides provide a secure and efficient RFID mutual authentication protocol which resists impersonation attacks on all of the entities and alow a backend server to search tag-related information efficiently. We conclude with analyzing the safety and efficiency among latest works.

• Journal of IKEEE
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• v.27 no.3
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• pp.239-245
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• 2023

Whitelist-based ransomware solution is known as being vulnerable to false impersonation attack using DLL injection attack. To solve this problem, it is proposed to monitor DLL injection attack and to integrate the monitoring result to ransomware solutions. In this paper, we show that attackers can easily bypass the monitoring mechanism and then illegally access files of a target system. It means that whitelist-based ransomware solutions are still vulnerable.

• The Journal of the Korea Contents Association
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• v.11 no.12
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• pp.88-93
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• 2011

Due to vulnerable authentication scheme of SIP, intruders can easily impersonate legitimate user. HTTP Digest authentication scheme or private key issued by trust third parties has been used to prevent impersonation attack. However, these methods have suffered security vulnerability or service delay due to computation overhead. In this paper, we propose new authentication method to generate automatically one-time password using the pre-shared password and time information of messages exchanged between SIP UA(User Agent) and SIP Registrar. This method protects against impersonation attack without significant modification of exiting SIP authentication procedure to build securer SIP environment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.1C
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• pp.25-34
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• 2005

Girault proposed a key agreement protocol based on his new idea of self-certified public key. Later Rueppel and Oorschot showed variants of the Girault scheme. All of these key agreement protocols inherit positive features of self-certified public key so that they can provide higher security and smaller communication overhead than key agreement protocols not based on self-certified public key. Even with such novel features, rigorous security analysis of these protocols has not been made clear yet. In this paper, we give rigorous security analysis of key agreement protocols based on self-certified public key. We use reduction among functions for security analysis and consider several kinds of active attacker models such as active impersonation attack, key-compromise impersonation attack, forward secrecy and known key security.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.3
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• pp.473-483
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• 2012

To achieve an entire end-to-end security, the classical authentication setting such that all participants have a same password is not practical since a password is not a common secret but a personal secret depending on an individual. Thus, an efficient client to client different password-based authenticated key agreement protocol (for short, EC2C-PAKA) has been suggested in the cross-realm setting. Very recently, however, a security weakness of the EC2C-PAKA protocol has been analyzed by Feng and Xu. They have claimed that the EC2C-PAKA protocol is insecure against a password impersonation attack. They also have presented an improved version of the EC2C-PAKA protocol. In this paper, we demonstrate that their claim on the insecurity of EC2C-PAKA protocol against a password impersonation attack is not valid. We show that the EC2C-PAKA protocol is still secure against the password impersonation attack. In addition, ironically, we show that the improved protocol by Feng and Xu is insecure against an impersonation attack such that a server holding password of Alice in realm A can impersonate Bob in realm B. We also discuss a countermeasure to prevent the attack.

• Journal of the Korea Society of Computer and Information
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• v.24 no.10
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• pp.41-48
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• 2019

In 2018, Cui et al proposed a three-factor remote user authentication scheme using biometrics. Cui et al claimed that their authentication scheme is vulnerable to eavesdropping attack, stolen smart card attack, and especially Dos(denial-of-service) attack. Also they claimed that it is safe to password guessing attack, impersonation attack, and anonymity attack. In this paper, however, we analyze Cui et al's authentication scheme and show that it is vulnerable to replay attack, insider attack, stolen smart card attack, and user impersonation attack, etc. In addition, we present the design flaws in Cui et al's authentication scheme as well.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.5
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• pp.25-34
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• 2009

Many conference systems over the Internet require authenticated group key agreement (AGKA) for secure and reliable communication. After Shamir [1] proposed the ID-based cryptosystem in 1984, ID-based AGKA protocols have been actively studied because of the simple public key management. In 2006, Zhou et al. [12] proposed two-round ID-based AGKA protocol which is very efficient in communication and computation complexity. However, their protocol does not provide user identification and suffers from the impersonation attack by malicious participants. In this paper, we propose improved ID-based AGKA protocol to prevent impersonation attack from Zhou et al.'s protocol. In our protocol, the malicious insider cannot impersonate another participants even if he knows the ephemeral group secret value. Moreover, our protocol reduces the computation cost from Zhou et al.'s protocol.