• Journal of Communications and Networks
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• v.8 no.4
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• pp.461-474
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• 2006

A group key exchange protocol is a cryptographic primitive that describes how a group of parties communicating over a public network can come up with a common secret key. Due to its significance both in network security and cryptography, the design of secure and efficient group key exchange protocols has attracted many researchers' attention over the years. However, despite all the efforts undertaken, there seems to have been no previous systematic look at the growing problem of key exchange over combined wired and wireless networks which consist of both stationary computers with sufficient computational capabilities and mobile devices with relatively restricted computing resources. In this paper, we present the first group key exchange protocol that is specifically designed to be well suited for this rapidly expanding network environment. Our construction meets simplicity, efficiency, and strong notions of security.

• Journal of Communications and Networks
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• v.12 no.2
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• pp.150-157
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• 2010

Understanding and optimizing the energy consumption of wireless devices is critical to maximize the network lifetime and to provide guidelines for the design of new protocols and interfaces. In this work, we first provide an accurate analysis of the energy performance of an IEEE 802.11 WLAN, and then we derive the configuration to optimize it. We further analyze the impact of the energy configuration of the stations on the throughput performance, and we discuss under which circumstances throughput and energy efficiency can be both jointly maximized and where they constitute different challenges. Our findings are that, although an energy-optimized configuration typically yields gains in terms of throughput as compared against the default configuration, it comes with a reduction in performance as compared against the maximum-bandwidth configuration, a reduction that depends on the energy parameters of the wireless interface.

• Journal of Communications and Networks
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• v.16 no.3
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• pp.258-263
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• 2014

A hierarchical identity-based broadcast encryption (H-IBBE) scheme is an identity-based broadcast encryption (IBBE) scheme in a hierarchical environment. In order to obtain secure H-IBBE schemes in the quantum era, we propose an H-IBBE scheme based on the learning with errors problemassumption.Our scheme achieves indistinguishability from random under adaptive chosen-plaintext and chosen-identity attacks in the random oracle model.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.169-170
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• 2008

To achieve secure communication in current ZigBee networks, encrypted messages using security keys need to be shared among devices. A link key shared by two devices is used for unicast communications, where the master key is the starting point for establishing a link key. The ZigBee protocol has some limitations in end-to-end key establishment, which are discussed and an improved end-to-end key establishment scheme is presented.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.8
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• pp.1145-1152
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• 2010

Currently economical communication technologies are needed for high speed data exchange at sea. Wireless environments at sea require some special communication security solutions as well. In this paper, an augmented WiMAX MMR protocol is proposed as a solution of the broadband data communications and security at sea environments fundamentally with no base station.

• Journal of Korean Academy of Nursing
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• v.41 no.1
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• pp.1-8
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• 2011

This study was conducted to investigate the clear concept of patient safety and obtain theoretical evidences. Methods Research was conducted using Walker & Avant's conceptual analysis process. Results: Patient safety was defined as a activity that minimizes and removes possible errors and injuries to patients. It includes a basic desire to secure the patient's right to safety, and the legal regulations and duties of medical teams. The results of the establishment of a safety culture are patient-centered medical treatment and caring. Antecedents were found to be open and clear communications, continuous education and training for health care personnel, sufficient allocation of qualified personnel, cooperation among departments, improvements in the recognition of patient safety. Consequences were found to be the provision of high quality medical care and treatment, and increase in patient satisfaction. Conclusion: Patient safety as defined by the results of this study will contribute to the foundation of institutionalization of the pursuit of patient safety and creation of a hospital culture focusing on patient safety as a first priority.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.10a
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• pp.837-840
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• 2000

For secure communications in using multicast applications such as Cable-TV, It is essential for us to manage shared keys to encrypt/decrypt data through crypto algorithm as DES, which is called Group Key Management. In GKM, It is a hot issue that reduces the number of join/leave operation and subgroup key in key tree model. In this paper, we propose optimized mechanism of group key management required for providing multicast security.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.6B
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• pp.414-422
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• 2012

In the paper we present optimized implementation method over sensor mote for HUMMINGBIRD2 algorithm, ultra-light symmetric cryptography. For efficient implementation we maximized the register usage and used optimized addressing method to reduce the encryption and decryption time. With the optimized encryption implementation, we can utilize the efficient secure network over resource constrained sensor mote.

• Proceedings of the KAIS Fall Conference
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• 2006.05a
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• pp.368-372
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• 2006

최근 MANET에서 보안적인 요소를 추가한 라우팅 연구가 활발하지만 기존에 제시된 방안들은 거짓 신고를 하는 악의적인 노드를 식별하지 못하는 문제점과 라우팅 측면에서 비효율적인 문제점이 있었다. 본 논문에서는 신고, 반박, 증명의 메시지를 이용하여 악의적인 노드의 여러 가지 공격을 차단하고 라우팅 측면에서 보다 효율적인 프로토콜을 제안한다. 제안하는 프로토콜은 여러 가지 MANET 라우팅 프로토콜에서 적용이 가능하며 라우팅 경로 선정 및 관리의 보안적인 부분을 추가하였다.

• Journal of Communications and Networks
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• v.4 no.2
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• pp.81-89
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• 2002

In this paper, we design and implement an efficient fair off-line electronic cash system based on Elliptic Curve Discrete Logarithm Problem (ECDLP), in which the anonymity of coins is revocable by a trustee in case of dispute. To achieve this, we employ the Petersen and Poupard s electronic cash system [1] and extend it by using an elliptic curve over the finite field GF($2^n$). This naturally reduces message size by 85% compared with the original scheme and makes a smart card to store coins easily. Furthermore, we use the Baek et al. s provably secure public key encryption scheme [2] to improve the security of electronic cash system. As an extension, we propose a method to add atomicity into new electronic cash system. To the best of our knowledge, this is the first result to implement a fair off-line electronic cash system based on ECDLP with provable security.