• Journal of Advanced Navigation Technology
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• v.15 no.5
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• pp.722-728
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• 2011

Most services need to have authentication protocols to verify users' eligibility in the network environment. For this, a lot of user authentication protocols have been researched and developed. Two of them, SPMA and I-SPMA protocols, introduced the lack of mutual authentication and vulnerability to the reply attack of the prior protocols and suggested revised protocols. Nevertheless, these protocols did not mention about the critical problem caused when the server and the client lose synchronization on the secret information between them. Therefore, in this paper, we analyze the security characteristics of the existing protocols and prove the vulnerability to the synchronization of the protocols.

• Journal of Information Processing Systems
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• v.7 no.4
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• pp.691-706
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• 2011

Since security and privacy problems in RFID systems have attracted much attention, numerous RFID authentication protocols have been suggested. One of the various design approaches is to use light-weight logics such as bitwise Boolean operations and addition modulo $2^m$ between m-bits words. Because these operations can be implemented in a small chip area, that is the major requirement in RFID protocols, a series of protocols have been suggested conforming to this approach. In this paper, we present new attacks on these lightweight RFID authentication protocols by using the Gr$\ddot{o}$bner basis. Our attacks are superior to previous ones for the following reasons: since we do not use the specific characteristics of target protocols, they are generally applicable to various ones. Furthermore, they are so powerful that we can recover almost all secret information of the protocols. For concrete examples, we show that almost all secret variables of six RFID protocols, LMAP, $M^2AP$, EMAP, SASI, Lo et al.'s protocol, and Lee et al.'s protocol, can be recovered within a few seconds on a single PC.

• Journal of Korea Society of Industrial Information Systems
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• v.10 no.2
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• pp.59-66
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• 2005

Recently, Ku and Chen(Ku-Chen) showed some problems in the password based remote user authentication scheme using smartcards proposed by Chien et al. and proposed an improvement from it. This paper shows some weaknesses in the Ku-Chen's scheme, especially the replay attacks, and proposes two authentication protocols to solve the problems in it. First of all, an authentication protocol using synchronized timestamps is proposed to solve the problem in the Ku-Chen's protocol. Then, a nonce-based authentication protocol is proposed to solve the inherent problems in the synchronized timestamp-based authentication protocols. The proposed authentication protocols support the advantages in the previous password-based authentication protocols and solve the problems in them effectively.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.1
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• pp.1-9
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• 2022

Global Navigation Satellite System (GNSS) provides location information using signals from multiple satellites. However, a spoofing attack that forges signals or retransmits delayed signals may cause errors in the location information. To prevent such attacks, authentication protocols considering the navigation message structure of each GNSS can be used. In this paper, we analyze the authentication protocols of Global Positioning System (GPS), Galileo, and BeiDou, and compare the performance of Navigation Message Authentication (NMA) of the above systems, using several performance indicators. According to our analysis, authentication protocols are similar in terms of performing NMA and using Elliptic Curve Digital Signature Algorithm (ECDSA). On the other hand, they are different in several ways, for example, whether to perform Spreading Code Authentication (SCA), whether to use digital certificates and whether to use Timed Efficient Stream Loss-tolerant Authentication (TESLA). According to our quantitative analysis, the authentication protocol of Galileo has the shortest time between authentications and time to first authenticated fix. We also show that the larger the sum of the navigation message bits and authentication bits, the more severely affected are the time between authentications and the time to first authenticated fix.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.6
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• pp.1323-1332
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• 2005

EAP (Extensible authentication protocol) is a sort of general framework for authentication rather than a specific authentication protocol. An important consequence of this is that EAP can accommodate a variety of authentication/key-establishment protocols for different internet access networks possibly integrated to a common IP core network This paper tries a comparative analysis of several specific authentication/key establishment protocols for EAP, and suggest a strategic viewpoint toward the question: which one to un. In addition, we tried to make things clear about an intellectual property right issue with regard to some password-based protocols.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.242-245
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• 2002

Authentication protocol as a part of security system has been growth rapidly since it was known that sending clear text password in the network is unsecured. Many protocols could be noted proposed to strengthen the authentication process. In 1985 an attempt to safeguard network services within Athena project resulting on the born of Kerberos 〔1〕〔8〕, one of the protocol that has a lot of attention from the research community. Several years later researchers were discovered some weaknesses carried by this protocol 〔2〕〔21〕. In 1992. EKE was introduced by Bellovin and Merrit. Since that time, many protocols introduced could be considered as its variant 〔5〕〔9〕〔13〕〔14〕. Some other protocols such as OKE〔5〕 and SRP〔18〕 although claimed different from EKE, they have the same basic mechanism in holding authentication process. Here, we explain the mechanism of those protocols, their strength and their weaknesses and shortcomings. Due to the limitations of the number of paper pages, only two types of authentication protocol can be explained here i.e EKE and SRP.

• ETRI Journal
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• v.31 no.4
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• pp.460-462
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• 2009

The emerging wireless networks require the design of new authentication protocols due to their dynamic nature and vulnerable-to-attack structure. Recently, Wu and others proposed a wireless authentication protocol which is claimed to be an improvement of the authentication protocol proposed by Lee and others which provides user anonymity. In this letter, we show that these protocols have a common flaw and that these protocols fail to provide user anonymity. We also propose a modification method to solve this problem.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.5
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• pp.105-114
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• 2005

There are several goals or properties which authentication protocols may have; some of them are key freshness, far-end aliveness, key confirmation, etc. Most of them have extensively been discussed and studied so far in the literature. 'Responsibility' and 'credit', which were first raised by Abadi as additional goals, received quite an exceptional treatment; there were little response from researchers about these new goals. It is surprising to see that these two properties have slipped through any investigation, successfully achieving the positions as the goals for authentication protocols. In this paper, we investigate these two new properties and their relations to authentication protocols, and answers to the question: what brings us credit and responsibility.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.4
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• pp.71-82
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• 2005

Though there are many authentication protocols for RFID system, only a few protocols support location privacy. Because of tag's hardware limitation, these protocols suffer from many security threats, especially from DoS (Denial of Service) attack. In this paper, we explain location privacy problem and show vulnerabilities of RFID authentication protocols. And then, we suggest an authentication protocol that is strong against location tracing, spoofing attack and DoS attack

• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.4
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• pp.139-150
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• 2009

Authentication and key exchange are fundamental for establishing secure communication channels over public insecure networks. Password-based protocols for authenticated key exchange are designed to work even when user authentication is done via the use of passwords drawn from a small known set of values. There have been many protocols proposed over the years for password authenticated key exchange in the three-party scenario, in which two clients attempt to establish a secret key interacting with one same authentication server. However, little has been done for password authenticated key exchange in the more general and realistic four-party setting, where two clients trying to establish a secret key are registered with different authentication servers. In fact, the recent protocol by Yeh and Sun seems to be the only password authenticated key exchange protocol in the four-party setting. But, the Yeh-Sun protocol adopts the so called "hybrid model", in which each client needs not only to remember a password shared with the server but also to store and manage the server's public key. In some sense, this hybrid approach obviates the reason for considering password authenticated protocols in the first place; it is difficult for humans to securely manage long cryptographic keys. In this work, we introduce a key agreement protocol and a key distribution protocol, respectively, that requires each client only to remember a password shared with its authentication server.