• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.4
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• pp.7-12
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• 2014

IETF (Internet Engineering Task Force) CoAP (Constrained Application Protocol) protocol is supported communication between sensor or actuator nodes by in a constrained environment, such as small amount of memory, and low power. CoAP and HTTP protocol can convert easily, and can use to monitor or controll the infrastructure utility through low-power sensor and actuator networks in IoT (Internet of Thing) and M2M (Machine-to-Machine) environment. IETF CoRE(Constrained RESTful environments) Working Group proposed CoAP protocol in 2010, and began to standardize it. Recently, CoAP protocol is published RFC (Request for Comments) 7252. In this paper, we design and implement of CoAP protocol for testing the interoperability in heterogeneous operating environments. For this experiment, we developed the CoAP client program based on Windows environment and CoAP server program in Linux environment to test the interoperability.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.05a
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• pp.111-112
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• 2023

IoT 산업의 규모가 커짐에 따라서 IoT 디바이스 간의 통신 프로토콜에 대한 위협도 증가하고 있으며, 이에 따라 IoT 프로토콜에 대한 보안의 중요성이 대두되고 있다. 하지만 IoT 프로토콜 중 비교적 최근에 등장한 프로토콜인 CoAP 프로토콜에 대한 연구는 아직 충분하지 않으며, CoAP에 대한 기존의 연구는 커버리지를 고려하지 않은 퍼저를 사용하였다. 따라서 이번 연구에서는 커버리지를 고려한 CoAP대상 퍼저를 개발하고 CoAP의 잠재적인 취약성을 점검한다. CoAP의 c 구현체인 libcoap 라이브러리를 대상으로 퍼징한 결과, 총 2개의 힙 버퍼 오버 플로우 취약점을 발견하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.5
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• pp.1189-1197
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• 2011

To manage sensing information such as temperature, humidity and so on efficiently, it is need to use special purpose protocol. In this reason, IETF WG proposed CoAP protocol, and it is on Internet draft. If it is possible to work on a specific protocol, sensor end-nodes and network devices will be managed efficiently. However, end-nodes have restricted resources, it is hard to applying to CoAP protocol directly. In this paper we analyse a CoAP protocol stack for USN. To verify this protocol quickly, at first we implemented CoAP protocol stack over PC environments. After the logical verification, we applied this protocol to the USN environment. To do this, we ported CoAP protocol to Cygwin environment, and proposed solutions for hardware dependencies, and it is verified through experiments.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.9
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• pp.11-20
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• 2014

For Web-based applications in IoT environment, IETF CoRE WG has standardizing the CoAP. One of limitations of CoAP is that CoAP standard does not consider the mobility management of the CoAP sensor node. In this paper, we propose the mobility management protocol of CoAP sensor node by considering the characteristics of the constrained network. The proposed mobility management protocol supports for Web client to be transmitted the sensing data from CoAP node reliably while the CoAP sensor moves into different wireless networks. To do this, we designed the architecture with the separate IP address management of CoAP sensor node and presented the mobility management protocol, which includes the holding and binding mode, in order to provide the reliable transmission. Finally, the numerical analysis and simulation with NS2 tool have been done for the performance evaluation in terms of the handover latency and packet loss with comparing the proposed mobility management protocol with other the existing mobility management protocols. The performance result shows that the proposed mobility management can provide the transmission of sensing data without the packet loss comparing with the existing mobility management protocol reliably.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.507-509
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• 2010

To manage a sensing information such as temperature, humidity efficiently, it's highly recommended suitable application protocol. In this reasons, IETF WG proposed a CoAP protocol, and it's on Internet draft. If it is possible to work on a specific protocol, sensor end nodes and network devices will be managed efficiently. However, end nodes have constrained resources, it is hard to apply a CoAP protocol. In this paper, we analyse a CoAP protocol for USN, and propose a applying method for CoAP over USN nodes.

• Electronics and Telecommunications Trends
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• v.28 no.6
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• pp.133-140
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• 2013

기존의 센서 접속 기술은 그 분야에 띠라 다양한 표준과 규격이 존재하였다. 빌딩 자동제어 및 제어 네트워크용으로는 BACnet이 있으며, 공장제어 및 계측제어를 위한 Modbus 등이 다양한 프로토콜이 존재한다. 최근 M2M(Machine-to-Machine) 및 IoT(Internet of Things), WoT(Web of Things) 시대로 접어 들음에 따라 센서 및 각종 디바이스 간에 상호 통신할 수 있는 공통 프로토콜이 필요하게 되었다. IoT 프로토콜로 IEIF(Internet Engineering Task Force) CoAP(Constrained Application Protocol) 프로토콜이 핵심 역할을 하고 있으며, 차세대 센서 접속 프로토콜로 IETF CoAP이 많이 사용될 것으로 예상된다. 본고에서는 IETF CoAP 표준화 동향 및 규격에 대해 살펴본다.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.04a
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• pp.262-265
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• 2017

IoT 환경에서 사용되는 프로토콜 중 IETF의 CoRE 워킹 그룹에서 채택한 IoT 프로토콜 CoAP가 표준으로 사용되고 있으며 IoT 인증 프로토콜에 대한 연구도 활발하게 이루어지고 있다. CoAP 프로토콜은 저전력, 저용량 메모리 등의 제한된 환경에서 IoT 센서 디바이스들 간의 통신을 지원한다. CoAP 프로토콜은 안전성을 제공하기 위해 DTLS와 함께 사용되는데, 점점 경량화 되어가는 IoT 환경에서 오버헤드가 존재하는 DTLS에 대해 개선되어야 할 사항들이 존재한다. 이를 개선하기 위해 DTLS의 문제점을 해결하기 위한 여러 연구들이 진행되고 있으며, 본 논문에서는 LESS 인증기법을 분석하고 이를 기반으로 보다 향상된 효율성을 제공하는 기법을 제안한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.147-153
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• 2016

Recently, IETF (Internet Engineering Task) working group has adopted CoAP (Constrained Application Protocol) as a standard IoT proctocol. CoAP is a specialized web transfer protocol for use with constrained nodes and constrained environment such as small memory and low power networks. In this paper, we design and implement a registration service with CoAP protocol based on RD(Resource Directory) to connect IoT nodes in mobile Internet environments. The resource directory between the mobile terminal and IoT nodes provides to discover the IoT nodes and get the context data. The mobile terminal has as the CoAP client and embedded IoT nodes includes as the CoAP server so that it can conveniently manage the constrained IoT nodes to get the context data and control devices in a mobile environments.

• Convergence Security Journal
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• v.17 no.5
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• pp.77-85
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• 2017

In this paper, we propose a key establishment scheme for multicast CoAP security. For multicast CoAP applications, a CoAP Request message from a CoAP client is sent to a group of CoAP servers while each CoAP server responds with a unicast CoAP Response message. In this case, the CoAP Request message should be secured with a group key common to both the CoAP client and servers, while a pairwise key(unicast key) should be employed to secure each CoAP Response message. In the proposed protocol, the CoAP client and the CoAP server establish the group key and the pairwise key using the ECDH in the initial CoAP message exchange process. The proposed protocol, which is highly efficient and scalable, can replace DTLS Handshake and it can support end-to-end security by setting pairwise keys.

• Journal of the Korea Convergence Society
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• v.9 no.11
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• pp.99-105
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• 2018

As the Internet of Thing(IoT) technology recently has become a big issue, many researches have been carried out to link the Internet of things with the home network system. Various home network systems are being implemented to connect many devices used in the home with the Internet and to control and operate the devices using a smart phone. However, existing protocols that operate on the Internet are not suitable for a limited environment such as low power, low capacity, and low performance. Therefore, the Internet Engineering Task Force (IETF) Working Group proposed the CoAP/6LoWPAN technology as a suitable protocol for internetworking IoT devices with the Internet in a limited environment and adopting it as a standard. In this paper, a smart home network system is implemented to control and operate various IoT devices in a home using CoAP/6LoWPAN in mobile environment. The performance of HTTP and CoAP such as data transmission time, data transmission rate is analyzed.