• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.10
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• pp.3572-3590
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• 2014

Cellular automata (CA) based cryptosystem has been studied for almost three decades, yet most of previously reported researches focus on the symmetric key encryption schemes. Up to now, few CA based public key encryption scheme has been proposed. To fill the gap, in this paper, we propose a new public key encryption scheme based on layered cellular automata (LCA). Specifically, in the proposed scheme, based on the T-shaped neighborhood structure, we combine four one-dimensional reversible CAs (set as the private key) to form the transition rules of a two-dimension CA, where the two-dimension CA is set as the corresponding public key. Based on the hardness assumption of the Decisional Dependent CA problem in LCA, we formally prove the proposed scheme is indistinguishably secure against the chosen-plaintext attack (IND-CPA). In addition, we also use a numeric example to demonstrate its feasibility. Finally, analysis of key space and time efficiency are also carried out along with RSA-1024, and the simulation results demonstrate that our proposed scheme is more efficient.

• Journal of KIISE:Information Networking
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• v.31 no.2
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• pp.179-187
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• 2004

Password authenticated key exchange protocols for the symmetric model are easier to design, analyze and are more efficient than ones for the asymmetric model, but they are most likely to be broken by server's compromise. Though the protocols with provable security for the asymmetric model such as PAK-X and SNAPI-X are introduced, they need large amount of computation compared with the standard Diffie-Hellman key exchange. We present a systematic and efficient way to transform password authenticated key exchange protocols for the symmetric model into protocols for the asymmetric model. Thus, an efficient protocol for the asymmetric model can be constructed by a systematic protocol with low computation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.12
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• pp.5616-5642
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• 2016

Different from traditional auctions, electronic auctions provide a platform to allow bidders and auctioneers merchandise to each other over network anytime and anywhere. Auctioneers can publish information of goods, and bidders can choose the interested targets through this bidding platform. To ensure the fairness and security of electronic auctions, Li et al. have proposed a practical electronic auction scheme which can confirm the requirement of strong anonymity, bidding privacy, and secret bidding price. However, we have found out that Li et al.'s scheme may lurk the risk of the denial-of-service attack during the bidding phase in a sealed-bid auction. Thus, we propose a brand-new sealed-bid auction mechanism, in which the essentials of e-auction can be firmly preserved. In particular, each bidder only needs to register at the center once and then can join to multiple plays launched by different auctioneers. Moreover, the correctness of mutual authentication is confirmed according to the BAN logic model.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.6
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• pp.113-124
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• 2002

Proposals for a password-based authenticated key exchange protocol that have been published so far almost concentrated on the provable security. But in a real environment such as mobile one, efficiency is a critical issue as security. In this paper we discuss the efficiency of PAK which is secure in the random oracle model ［l］. Among 4 hash functions in PAK the instantiation for $H_1$, which outputs a verifier of the password, has most important effect on the computational efficiency. We analyze two different methods for $H_1$ suggested in ［1］ and we show that $H_{lq}$ has merits in transforming to EC or XTR variants as well as in the efficiency. As an efficient variant. we propose PAK2-EC and PAK2-XTR which do not require any additional step converting a hash output into a point of elliptic curve or XTR subgroup when compared to the previous work on the PAK［2］. Finally we compare PAK2 with the password-based authenticated key exchange protocols such as SPEKE, SRP, and AMP.

• Journal of Digital Contents Society
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• v.16 no.1
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• pp.25-32
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• 2015

With the increased frequency of crime such as assaults and sexual violence, the reliance on CCTV in arresting criminals has increased as well. However, CCTV, which should be monitored by human labor force at all times, has limits in terms of budget and man-power. Thereby, the interest in intelligent security system is growing nowadays. Expanding the techniques of an objects behavior recognition in previous studies, we propose a system to detect forms of violence between 2~3 objects from images obtained in CCTV. It perceives by detecting the object with the difference operation and the morphology of the background image. The determinant criteria to define violent behaviors are suggested. Moreover, provable decision metric values through measurements of the number of violent condition are derived. As a result of the experiments with the threshold values, showed more than 80% recognition success rate. A future research for abnormal behaviors recognition system in a crowded circumstance remains to be developed.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.2
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• pp.105-115
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• 2011

User authentication service is an absolutely necessary condition while securely implementing an IT service system. It allows for valid users to securely log-in the system and even to access valid resources from database. For efficiently and securely authenticating users, smart-card has been used as a popular tool because of its convenience and popularity. Furthermore the smart-card can maintain its own power for computation and storage, which makes it easier to be used in all types of authenticating environment that usually needs temporary storage and additional computation for authenticating users and server. First, in 1981, Lamport has designed an authentication service protocol based on user's smart-card. However it has been criticized in aspects of efficiency and security because it uses hash chains and the revealment of server's secret values are not considered. Over the years, many smart-card based authentication service protocol have been designed. Very recently, Xu, Zhu, Feng have suggested a provable and secure smart-card based authentication protocol. In this paper, first, we define all types of attacks in the smart-card based authentication service. According to the defined attacks, however, the protocol by Xu, Zhu, Feng is weak against an attack that an attacker with secret values of server is able to impersonate a valid user without knowing password and secret values of user. An efficient and secure countermeasure is suggested, then the security is analyzed.

• The Korean Journal of Archival Studies
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• no.25
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• pp.3-46
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• 2010

Digital records management is one whole system in which many social and technical elements are interacting. To maintain the trustworthiness, the repository needs periodical audit and certification. Thus, individual electronic records management agency needs toolkit that can be used to self-evaluate their trustworthiness continuously, and self-assess their atmosphere and system to recognize deficiencies. The purpose of this study is development of self-certification toolkit for repositories, which synthesized and analysed such four international standard and best practices as OAIS Reference Model(ISO 14721), TRAC, DRAMBORA, and the assessment report conducted and published by TNA/UKDA, as well as MoRe2 and current national laws and standards. As this paper describes and demonstrate the development process and the framework of this self-certification toolkit, other electronic records management agencies could follow the process and develop their own toolkit reflecting their situation, and utilize the self-assessment results in-house. As a result of this research, 12 areas for assessment were set, which include (organizational) operation management, classification system and master data management, acquisition, registration and description, storage and preservation, disposal, services, providing finding aids, system management, access control and security, monitoring/audit trail/statistics, and risk management. In each 12 area, the process map or functional charts were drawn and business functions were analyzed, and 54 'evaluation criteria', consisted of main business functional unit in each area were drawn. Under each 'evaluation criteria', 208 'specific evaluation criteria', which supposed to be implementable, measurable, and provable for self-evaluation in each area, were drawn. The audit and certification toolkit developed by this research could be used by digital repositories to conduct periodical self-assessment of the organization, which would be used to supplement any found deficiencies and be used to reflect the organizational development strategy.