• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권4호
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• pp.1941-1960
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• 2019

Unmanned aerial vehicles (UAVs), acting as mobile base stations (BSs), can be deployed in the typical fifth-generation mobile communications (5G) scenarios for the purpose of substantially enhancing the radio coverage. Meanwhile, UAV aided underlay device-to-device (D2D) communication mode can be activated for further improving the capacity of the 5G networks. However, this UAV aided D2D communication system is more vulnerable to eavesdropping attacks, resulting in security risks. In this paper, the D2D receivers work in full-duplex (FD) mode, which improves the security of the network by enabling these legitimate users to receive their useful information and transmit jamming signal to the eavesdropper simultaneously (with the same frequency band). The security communication under the UAV coverage is evaluated, showing that the system's (security) capacity can be substantially improved by taking advantage of the flexible radio coverage of UAVs. Furthermore, the closed-form expressions for the coverage probabilities are derived, showing that the cellular users (CUs)' secure coverage probability in downlink transmission is mainly impacted by the following three factors: its communication area, the relative position with UAV, and its eavesdroppers. In addition, it is observed that the D2D users or DUs' secure coverage probability is relevant to state of the UAV. The system's secure capacity can be substantially improved by adaptively changing the UAV's position as well as coverage.

• 정보보호학회논문지
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• 제12권2호
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• pp.89-100
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• 2002

본 논문에서는 안전한 그룹통신을 위한 그룹키 관리 기법을 기반으로 이동네트워크 환경에서의 그룹키 관리 구조와 멤버의 인종과 키 설정을 위한 프로토콜을 제안한다. 기존의 대부분의 그룹키 관리기법들이 초기의 키 서버와 멤버간의 안전한 공유키 설정을 위해 공개키 기반의 인증서 교환을 이용하였으나, 본 논문에서는 인증서의 교환과 검증으로 인한 대역폭 소모의 효율성을 위해 ICPK를 이용해서 그룹 내에서의 멤버의 인증과 키 교환에 이용하도록 한다. 또한, 전체 그룹을 이동호스트들에 대한 셀 그룹과 셀 그룹 관리자들에 대한 제어그룹으로 구분하여 셀 그룹마다 셀 그룹 관리자가 관리함으로써 멤버십의 변경으로 인한 영향을 지역적으로 한정시킨다.

• 한국정보보호학회:학술대회논문집
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• 한국정보보호학회 2002년도 종합학술발표회논문집
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• pp.121-124
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• 2002

In this paper, we present a secure on-line lottery protocol which consists of three entities: the players, the lottery provider and the bank. We utilize blind signature and hash chain technique as basic building blocks. Our protocol faithfully satisfies the general security requirements to deal with electronic transactions in safe. The proposed protocol reduces the number of communications and all transactions are executed through the Internet(On-line). By using bank as a notary and bulletin board managed by the lottery provider, we can easily settle down potential disputes which frequently occur during commercial transactions.

• 한국통신학회논문지
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• 제33권8B호
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• pp.735-744
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• 2008

본 연구에서는 네트워크 기반 서비스거부공격에 대응하여 웹서버의 가용성을 향상 시킬 수 있는 보안노드를 설계하고자, 과부하 상태에서 문서의 인기도에 기반 하여 신규 세션 허용을 제어할 수 있는 동적 서비스 메커니즘을 품질 향상방안으로 제안하였다. 그 결과, 과부하가 지속될수록 기존 방식에 비해 웹서비스 요청 세션에 대한 연결접속률과 연결완성률이 크게 향상됨을 알 수 있었다.

• 한국통신학회논문지
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• 제24권6A호
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• pp.894-904
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• 1999

본 논문에서는 실제 채널 환경에 효율적인 암호 통신을 제공하는 동기식 스트림 암호 통신 체계를 설계하였으며, 그 암호 시스템의 비도를 분석하였다. 제안된 시스템의 주요 구성 부분은 동기 패턴, 세션 키, 키 수열 발생기이며, 이에 대한 시스템 성능을 랜덤성, 주기, 선형 복잡도, 상관 면역도에 따라 비도 분석하여 무선 채널에 적합함을 판정하였다. 시뮬레이션 결과는 10-1과 10-2채널 오류 환경에서 영상 신호를 이용하여 암복호의 타당성으로 나타내었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권12호
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• pp.5135-5149
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• 2015

Communications among multi-party must be fast, cost effective and secure. Today's computing environments such as internet conference, multi-user games and many more applications involve multi-party. All participants together establish a common session key to enable multi-party and secure exchange of messages. Multi-party password-based authenticated key exchange scheme allows users to communicate securely over an insecure network by using easy-to-remember password. Kwon et al. proposed a practical three-party password-based authenticated key exchange (3-PAKE) scheme to allow two users to establish a session key through a server without pre-sharing a password between users. However, Kwon et al.'s scheme cannot meet the security requirements of key authentication, key confirmation and anonymity. In this paper, we present a novel, simple and efficient multi-party password-based authenticated key exchange (M-PAKE) scheme based on the elliptic curve cryptography for mobile environment. Our proposed scheme only requires two round-messages. Furthermore, the proposed scheme not only satisfies security requirements for PAKE scheme but also achieves efficient computation and communication.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권2호
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• pp.935-949
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• 2016

In this paper, we present a novel authenticated group key distribution scheme for large and dynamic multicast groups without employing traditional symmetric and asymmetric cryptographic operations. The security of our scheme is mainly based on the basic theories for solving linear equations. In our scheme, a large group is divided into many subgroups, where each subgroup is managed by a subgroup key manager (SGKM) and a group key generation center (GKGC) further manages all SGKMs. The group key is generated by the GKGC and then propagated to all group members through the SGKMs, such that only authorized group members can recover the group key but unauthorized users cannot. In addition, all authorized group members can verify the authenticity of group keys by a public one-way function. The analysis results show that our scheme is secure and efficient, and especially it is very appropriate for secure multicast communications in large and dynamic client-server networks.

• 한국통신학회논문지
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• 제41권3호
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• pp.298-300
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• 2016

본고에서는 중계 공격 성공확률을 낮추기 위해 RFID 리더가 무요청(void challenge)을 보내더라도 태그가 응답하는 거리 제한 프로토콜을 제안한다. Full challenge 비율에 따른 공격 성공 확률을 분석하고, 기존의 프로토콜과 비교 분석하여 제안 프로토콜의 공격 성공 확률이 낮음을 보인다.

• IEIE Transactions on Smart Processing and Computing
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• 제4권6호
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• pp.443-449
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• 2015

This paper considers the physical layer security problem for a two-way vehicle-to-vehicle network, where the two source vehicles can only exchange information through an untrusted relay vehicle. The relay vehicle helps the two-way transmission but also acts as a potential eavesdropper. Each vehicle has a random velocity. By exploiting the random carrier frequency offsets (CFOs) caused by random motions, a secure double-differential two-way relay scheme is proposed. While achieving successful two-way transmission for the source vehicles, the proposed scheme guarantees a high decoding error floor at the untrusted relay vehicle. Average symbol error rate (SER) performance for the source vehicles and the untrusted relay vehicle is analyzed. Simulation results are provided to verify the proposed scheme.

• IEIE Transactions on Smart Processing and Computing
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• 제2권3호
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• pp.176-187
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• 2013

Message replay, malicious Access Point (AP) associations and Denial of Service (DoS) attacks are the major threats in Wireless LANs. These threats are possible due to a lack of proper authentication and insecure message communications between wireless devices. Current wireless authentication & key exchange (AKE) schemes and security protocols (WEP, WPA and IEEE 802.11i) are not sufficient against these threats. This paper presents a novel Secure WLAN Authentication Scheme (SWAS). The scheme introduces the delegation concept of mobile authentication in WLANs, and provides mutual authentication to all parties (Wireless Station, Access Point and Authentication Server). The messages involved in the process serve both authentication and key refreshing purposes. The scheme enhances the security by protecting the messages through cryptographic techniques and reduces the DoS impact. The results showed that cryptographic techniques do not result in extra latencies in authentication. The scheme also reduces the communication cost and network overhead.