• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.5
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• pp.49-57
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• 2008

User authentication and key agreement are very important components to provide secure home network service. Although the TTA adopted the EEAP-PW protocol as a user authentication and key transmission standard, it has some problems including not to provide forward secrecy. This paper first provides an analysis of the problems in EEAP-PW and then proposes a new attribute-based authenticated key agreement protocol, denoted by EEAP-AK. to solve the problems. The proposed protocol supports the different level of security by diversifying network accessibility for the user attribute after the user attribute-based authentication and key agreement protocol steps. It efficiently solves the security problems in the EEAP-PW and we could support more secure home network service than the EEAP-AK.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.4
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• pp.111-122
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• 2008

Web service is defined to support interoperable machine to machine interaction over a network and defined as distributed technologies. Recently in web service environment, security has become one of the most critical issues. An attacker may expose user privacy and service information without authentication. Furthermore, the users of web services must temporarily delegate some or all of their behalf. This results in the exposure of user privacy information by agents. We propose a delegation model for providing safety of web service and user privacy in ubiquitous computing environments. In order to provide safety of web service and user privacy, XML-based encryption and a digital signature mechanism need to be efficiently integrated. In this paper, we propose web service management server based on XACML, in order to manage services and policies of web service providers. For this purpose, we extend SAML to declare delegation assertions transferred to web service providers by delegation among agents.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.11 no.5
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• pp.53-62
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• 2001

Fast diffusion of personal computer and network, and developed security technology are augmenting specific gravity of convenient and safe electronic voting system supplementing much problems of existent off-line vote form. But in spite of enlargement of these weight, much limitations are extravagant. Specially, problem that secure voter\`s anonymousness and accuracy of poll can be important urea that judge if electronic voting system can be applied actually. Also, problems such as buying and selling of vote remain to subject that must solve yet. In this paper, we introduce items that is considered to design the safe electronic voting system, and present limitation of electronic polling system announced in [1]. And we propose improvement way. Improved protocol keeping advantages that is presented in [1], designed to keep away voter\`s anonymousness defamation by conspiracy of Election Administration Committee and Totaling Committee, and block unlawful election intervention as original.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.6
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• pp.149-161
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• 2003

Partially blind signature scheme allows the signer to insert non-removable common information into his blind signature. Blind signatures providing with both users privacy and data authenticity are one of key parts of information systems, such anonymous electronic cash and electronic voting as typical examples. Partially blind signature, with which all expired e-cash but for still-alive can be removed from the banks database, copes well with the problem of unlimited growth of the banks' database in an electronic cash system. In this paper we propose an efficient ID-based partially blind signature scheme using the Weil-pairing on Gap Diffie-Hellman group. The security of our scheme relies on the hardness of Computational Diffie-Hellman Problem. The proposed scheme provides higher efficiency than existing partially blind signature schemes by using three-pass protocol between two participants, the signer and requesters also by reducing the computation load. Thus it can be efficiently used in wireless environment.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.5
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• pp.59-71
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• 2005

A RFID (Radio Frequency Identification) system receives attention as the technology which can realize the ubiquitous computing environment. However, the feature of the RFID tags may bring about new threats to the security and privacy of individuals. Recently, Juels proposed the minimalist cryptography for very low-cost RFID tags, which is secure. but only under the impractical assumption such that an adversary is allowed to eavesdrop only the pre-defined number of sessions. In this paper, we propose a scheme to protect privacy for very low-cost RFID systems. The proposed protocol uses only bit-wise operations without my costly cryptographic function such as hashing, encryption which is secure which is secure against an adversary who is allowed to eavesdrop transmitted message in every session any impractical assumption. The proposed scheme also is more efficient since our scheme requires less datas as well as few number of computations than Juels's scheme.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.6
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• pp.93-103
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• 2005

As the usage of XML documents increases the requirement of security for XML documents is growing. Especially it is very important to solve the problem of access control to XML object which shares in the environment where various users connect to each others. In this paper, we propose the access control model and mechanism which is combined with role hierarchy in the RBAC and hierarchical key derivation/assign method for the access to XML object. So we implement the access control mechanism by including hierarchical key derivation method. The technique, we proposed, gives not only the benefit in management which RBAC provides in access control to XML objects, but also it ran help derive a lower layer key from the higher layer user's. This feature decrease the number of keys managed in each role hierarchy in comparison with previous methods.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.3
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• pp.17-28
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• 2006

The appearance of variant malicious codes using obfuscation techniques is accelerating the spread of malicious codes around the detection by a vaccine. n a system does not patch detection patterns for vulnerabilities and worms to the vaccine, it can be infected by the worms and malicious codes can be spreaded rapidly to other systems and networks in a few minute. Moreover, It is limited to the conventional pattern based detection and treatment for variants or new malicious codes. In this paper, we propose a method of behavior based detection by the static analysis, the dynamic analysis and the dynamic monitoring to detect a malicious code using obfuscation techniques with the PE compression. Also we show that dynamic monitoring can detect worms with the PE compression which accesses to important resources such as a registry, a cpu, a memory and files with the proposed method for similarity.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.5
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• pp.15-24
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• 2006

Many computer security systems use the signatures of well-known attacks to respond to hackers. For these systems, it is very important to get the accurate signatures of new attacks as soon as possible. For this reason, honeypots and honeypot farms have been actively researched. However, they can only collect a small amount of information because hackers have a strong tendency to directly attack servers of which IP addresses are allocated. In this paper, we propose an unused ports-based decoy system to redirect hackers toward honeypots. This system opens unused ports to lure hackers. All interactions with the unused ports are considered as suspect, because the ports aren't those for real service. Accordingly, every request sent to the unused ports is redirected to a honeypot. Consequently, this system enables honeypots to collect information about hackers attacking real servers other than themselves.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.4
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• pp.161-169
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• 2011

There is a consensus in the field of vehicular network security that public key cryptography should be used to secure communications. A certificate revocation list (CRL) should be distributed quickly to all the vehicles in the network to protect them from malicious users and malfunctioning equipment as well as to increase the overall security and safety of vehicular networks. Thus, a major challenge in vehicular networks is how to efficiently distribute CRLs. This paper proposes a CRL distribution method aided by terrestrial digital multimedia broadcasting (T-DMB). By using T-DMB data broadcasting channels as alternative communication channels, the proposed method can broaden the network coverage, achieve real-time delivery, and enhance transmission reliability. Even if roadside units are not deployed or only sparsely deployed, vehicles can obtain recent CRLs from the T-DMB infrastructure. A new transport protocol expert group (TPEG) CRL application was also designed for the purpose of broadcasting CRLs over the T-DMB infrastructure.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.4
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• pp.101-114
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• 2011

As it seems like critical information leakages have been increasing due to industrial espionage and malicious internal users, the importance of introducing audit and log security technology is growing every now and then. In this paper, we suggest the session logging system for the company's internal control to meet the SOX legislation level, by monitoring and analyzing users behaviors connecting to the business-critical Operating System. The system proposed in this paper aims to monitor the user's illegal activities in the Operating System, and to present the clear evidence of purpose of those activities by detailed logs. For this purpose, we modified Operating System by adding multiple services suggested in this paper. These services utilize interfaces provided by the existing Operating System and add functions to control access and get logs. The system saves and manages session logs of users or administrators connected to the server with centralized log storage. And the system supports session log searching and lookup features required by SOX legislation for the company's internal controls with the level of computer forensics and logging technology.