• Review of KIISC
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• v.28 no.5
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• pp.26-30
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• 2018

사물인터넷 서비스는 다양한 기능과 성능을 갖는 디바이스와 게이트웨이, 플랫폼, 서비스가 서로 상호 연동/통신함으로써 실현된다. 해당 서비스의 안전성 및 신뢰성을 보장하기 위해선 서비스 각 구성 요소에 적절한 보안 기술이 필요하다. 서비스 및 API 수준에서는 OpenID-connect, OAuth2, SAML, XACML과 같은 인증/인가, 접근 제어 기법이 필요하며, 플랫폼 및 프로토콜 수준에서는 MQTT, CoAP, HTTPS, RSPF 프로토콜 및 보안 절차가 필요하다. 한편, 이들 보안 기술은 공통적으로 TLS/DTLS 보안 프로토콜을 사용한다는 특성을 가진다. 이에, 본 논문에서는 사물인터넷의 디바이스, 게이트웨이, 플랫폼에서 손쉽게 사용될 수 있도록 TLS/DTLS 보안 칩 개발 사례를 소개하고 이를 TLS 오픈 소프트웨어 스택인 mbedTLS와의 연동 사례를 소개함으로써 사물인터넷 구성 요소에 공통적으로 활용 가능한 보안 기술 구현 사례를 살펴본다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.9
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• pp.707-714
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• 2013

IoT, which can be regarded as an enhanced version of M2M communication technology, was proposed to realize intelligent thing to thing communications by utilizing Internet connectivity. Things in IoT are generally heterogeneous and resource constrained. Also such things are connected with each other over LLN(low power and lossy Network). Confidentiality, mutual authentication and message origin authentication are required to make a secure service in IoT. Security protocols used in traditional IP Networks cannot be directly adopted to resource constrained devices in IoT. Under the respect, a IETF standard group proposes to use lightweight version of DTLS protocol for supporting security services in IoT environments. However, the protocol can not cover up all of very constrained devices. To solve the problem, we propose a scheme which tends to support mutual authentication and session key agreement between devices that contain only a single crypto primitive module such as hash function or cipher function because of resource constrained property. The proposed scheme enhances performance by pre-computing a session key and is able to defend various attacks.

• 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.

• The KIPS Transactions:PartC
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• v.14C no.1 s.111
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• pp.55-64
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• 2007

Behind the popularity of VoIP in these days, it may present significant security challenges in privacy and accounting. Authentication and message encryption are considered to be essential mechanisms in VoIP to be comparable to PSTN. SIP is responsible for setting up a secure call in VoIP. SIP employs TLS, DTLS or IPSec combined with TCP, UDP or SCTP as a security protocol in VoIP. These security mechanisms may introduce additional overheads into the SIP performance. However, this overhead has not been understood in detail by the community. In this paper we present the effect of the security protocol on the performance of SIP by comparing the call setup delays among security protocols. We implement a simulation of the various combinations of three security protocols and three transport layer protocols suggested for SIP. UDP with any combination of security protocols performs a lot better than the combination of TCP. TLS over SCTP may impose higher impact on the performance in average because TLS might have to open secure channels as the same number of streams in SCTP. The reasons for differences in the SIP performances are given.

• Journal of KIISE:Information Networking
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• v.36 no.3
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• pp.184-190
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• 2009

WiBro has advantages when both WLAN and 3G UMTS are adopted. Much research is being carried out in this area. However, the WiBro specification does not consider end-to-end security. Hence, another security protocol has to be adopted to support secure communication. Most previous research only focused on WiBro MAC performance improvement or security. In this paper, we adopt a security protocol such as IPsec, TLS, and DTLS, well known end-to-end security protocols, to make full use of WiBro in the IP network. Using NS-2 we simulated the adoption of end-to-end security protocol and evaluated performance and usability. Simulation shows DTLS had some performance advantages. All the protocols, TLS and IPsec are also suitable for use in WiBro.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.10a
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• pp.785-788
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• 2016

최근 IoT 프로토콜 가운데 가장 활발히 논의되는 프로토콜로 CoAP(Constrained Application Protocol)이 있다. CoAP은 4가지 보안모드로 운영된다. 그 중 3가지 모드인 PresharedKey, RawPublicKey, Certificate 모드의 경우 DTLS(Datagram Transport Layer Security)가 적용된 방식이다. 반면 NoSec 모드는 DTLS가 적용되지 않은 기본방식이다. 본 논문에서는 DTLS의 복잡한 Handshake 방식으로 인한 전력소모 및 Performance의 저하를 고려한 새로운 방식을 제안한다. NoSec 환경의 CoAP 프로토콜에 S-Broker(Secure-Broker)를 적용한 security 및 performance 향상 방안이다. 제안한 방식으로 경량화 통신을 구현하여 무결성과 보안 강도를 높였다. 추가적으로 Proxy의 forwarding 기능과 caching 기능을 구현하여 성능의 향상을 도모한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.12
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• pp.822-830
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• 2014

Recently, A Security service in Internet environments has been more important and the use of SSL & TLS is increasing for the personel homepage as well as administrative institutions. Also, IETF suggests using DTLS, which can provide a security service to constrained devices with lower CPU power and limited memory space under IoT environments. In this paper, we implement LEA(Lightweight Encryption Algorithm) algorithm and apply it to OpenSSL. The implemented algorithm is compared with other symmetric encryption algorithms such as AES etc, and it shows the superior performance in calculation speed.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.5
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• pp.35-44
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• 2009

To protect sensitive personal information, data will be stored in encrypted form. However in order to retrieve these encrypted data without decryption, there need efficient search methods to enable the retrieval of the encrypted data. Until now, a number of searchable encryption schemes have been proposed but these schemes are not suitable when dynamic users who have the permission to access the data share the encrypted data. Since, in previous searchable encryption schemes, only specific user who is the data owner in symmetric key settings or has the secret key corresponding to the public key for the encrypted data in asymmetric key settings can access to the encrypted data. To solve this problem, Stephen S. Yau et al. firstly proposed the controlled privacy preserving keyword search scheme which can control the search capabilities of users according to access policies of the data provider. However, this scheme has the problem that the privacy of the data retrievers can be breached. In this paper, we firstly analyze the weakness of Stephen S. Yau et al.'s scheme and propose privacy preserving keyword search with access control. Our proposed scheme preserves the privacy of data retrievers.