• The KIPS Transactions:PartC
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• v.15C no.6
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• pp.469-480
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• 2008

The recently proposed RFID(Radio Frequency Identification) authentication protocol based on a hash function can be divided into two types according to the type of information used for authentication between a reader and a tag: either a value fixed or one updated dynamically in a tag memory. In this paper, we classify the protocols into a static ID-based and a dynamic-ID based protocol and then analyze their respective strengths and weaknesses. Also, we define a new security model including forward/backward traceability, synchronization, forgery attacks. Based on the model, we analyze the previous protocols and propose a new dynamic-ID based RFID mutual authentication protocol. Our protocol provide enhanced RFID user privacy compared to previous protocols and identify a tag efficiently in terms of the operation quantity of a tag and database.

• The KIPS Transactions:PartC
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• v.9C no.4
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• pp.597-604
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• 2002

Changing group key is necessary for the remaining members when a new member joins or a member leaves the group in multicast communications. It is required to guarantee perfect forward and backward confidentiality. Unfortunately, in large groups with frequent membership changes, key changes become the primary bottleneck for scalable group. In this paper, we propose a novel approach for providing efficient group key distribution in large and dynamic groups. Unlike existing secure multicast protocols, our protocol is scalable to large groups because both the frequency and computational overhead of re-keying is determined by the size of a subgroup instead of the size of the whole group, and offers mechanism to prevent the subgroup managers with group access control from having any access to the multicast data that are transfered by sender. It also provides security service for preserving privacy in wireless computing environments.

• The KIPS Transactions:PartC
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• v.16C no.3
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• pp.347-356
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• 2009

In an RFID search protocol, a reader uses designated query to determine whether a specific tag is in the vicinity of the reader. This fundamental difference makes search protocol more vulnerable to replay attacks than authentication protocols. Due to this, techniques used in existing RFID authentication protocols may not be suitable for RFID search protocols. In this paper, we propose two RFID search protocols, one based on static ID and the other based on dynamic ID, which use counter to prevent replay attacks. Moreover, we propose a security model for RFID search protocols that includes forward/backward traceability, de-synchronization and forgery attack. Based on this model, we analyze security of our protocols and related works.

• 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.13 no.5
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• pp.105-112
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• 2003

In this raper, we propose two simple and efficient key agreement protocols, called SEKA-H and SEKA-E, which use a pre-shared password between two parties for mutual authentication and agreeing a common session key. The SEKA-H protocol uses a hash function to verify an agreed session key. The SEKA-E Protocol, a variant of SEKA-H, uses an exponentiation operation in the verification phase. They are secure against the man-in-the-middle attack the password guessing attack and the Denning-Sacco attack and provide the perfect forward secrecy. The SEKA-H protocol is very simple in structure and provides good efficiency compared with other well-known protocols. The SEKA-E protocol is also comparable with the previous protocols.

• Journal of Internet Computing and Services
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• v.9 no.2
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• pp.83-88
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• 2008

Session initiation protocol (SIP) is an application-layer prolocol to initiate and control multimedia client session. When client ask to use a SIP service, they need to be authenticated in order to get service from the server. Authentication in a SIP application is the process in which a client agent present credentials to another SIP element to establish a session or be granted access to the network service. In 2005, Yang et al. proposed a key exchange and authentication scheme for use in SIP applications, which is based on the Diffie-Hellman protocol. But, Yang et al.'s scheme is not suitable for the hardware-limited client and severs, since it requires the protocol participant to perform significant amount of computations (i.e., four modular exponentiations). Based on this observation. Huang and Wei have recently proposed a new efficient key exchange and authentication scheme thor improves on Yang et al.'s scheme. As for security, Huang and Wei claimed, among others, that their scheme is resistant to offline dictionary attacks. However, the claim turned out to be untrue. In this paper, we show thor Huang and Wei's key exchange and authentication scheme is vulnerable to on offline dictionary attack and forward secrecy.

• Information and Communications Magazine
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• v.30 no.10
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• pp.18-24
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• 2013

협력 지능형 교통 시스템 (C-ITS: Cooperative Intelligent Transportation System)은 차량이 도로 인프라 또는 다른 차량과 서로 통신하면서 전방의 교통사고 및 장애물과 주변 차량 정보를 공유하여 위험상황을 피할 수 있도록 사전에 경고하는 미래형 교통체계이다. C-ITS는 보행자 및 차량의 안전을 향상시키고 배출탄소량 감소 및 교통물류의 효율성을 증가시킬 수 있는 미래사회의 핵심 인프라가 될 전망이다. C-ITS의 성공적인 실현을 위해서는 다중 센서 융 복합 기반 교통정보 수집, 교통정보를 쌍방향으로 유통하기 위한 통합 무선 통신망, 스마트 기기와 이동통신망을 활용한 실시간 교통정보 수집 및 빅 데이터 처리와 주문형 서비스 제공 등의 핵심 기술 개발이 필요하다. 본 고에서는 협력형 교통 환경에서의 C-ITS 구조 및 관련 핵심 요소 기술을 소개하고, 앞으로 해결할 과제를 소개 한다.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.1
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• pp.51-58
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• 2013

This paper describes the design and implementation of the PKI-based EAI system which is used for delivery of sensitive personal information between business systems. For this purpose, we propose a key exchange protocol with some key process : Diffie-Hellman Schema is used to provide forward secrecy, public key-based digital signature is used for EAI Server authentication, data integrity. In addition, in order to minimize the performance impact on the overall EAI systems. The EAI server was designed simply to be used only as a gateway. This paper shows the implementation of Korea public key authentication algorithm standard and a symmetric encryption algorithm for data encryption.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.6
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• pp.1077-1082
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• 2019

The development of computing technology and networking has developed into a fundamental technology of the Fourth Industrial Revolution, which provides a ubiquitous environment. In the ubiquitous environment, the IoT environment has become an issue so that various devices and the things can be actively accessed and connected. Also, the RFID system using the wireless identification code attaches an RFID tag to the object, such as the production and distribution of products. It is applied to the management very efficiently. EPCglobal is conducting a research on RFID system standardization and various security studies. Since RFID systems use wireless environment technology, there are more security threats than wire problems. In particular, failure to provide confidentiality, indistinguishability, and forward safety could expose them to various threats in the Fourth Industrial Revolution. Therefore, this study analyzes the standard method of EPCgolbal and proposes RFID security method using hash code that can consider the amount of computation.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.5
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• pp.17-30
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• 2008

In the paper, we consider password-based authenticated key exchange with different passwords, where the users do not share a password between themselves, but only with the server. The users make a session key using their different passwords with the help of the server. We propose an efficient password-based authenticated key exchange protocol with different passwords which achieves forward secrecy without random oracles. In fact this amount of computation and the number of rounds are comparable to the most efficient password-based authenticated key exchange protocol in the random oracle model. The protocol requires a client only to memorize a human-memorable password, and all other information necessary to run the protocol is made public.