• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.5
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• pp.863-874
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• 2021

Distributed key generation (DKG) with trustless setup is a cryptographic protocol that distributes Shamir secret shares of a private key to participants while keeping the actual private key hidden to the participants. Also, by extending it to a threshold signature protocol, digital signatures can be generated without construction of private keys. This paper proposes a recovery protocol maintaining trustless setup assumptions, in particular to the useful (1,3) share structure. The proposed protocol meets same levels of security requirements with DKG in terms of correctness and secrecy. The protocol can also enable delegation and revocation of digital sign rights for blockchain-based asset management.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.3
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• pp.563-572
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• 2016

Recently, a plenty of credit card payment protocols have been proposed in Korea. Several features of proposed protocols include: using passwords for user authentication in stead of official certificate for authenticity, and no need to download additional security module via ActiveX into user's devices. In this paper, we suggest two new credit card payment protocols that use both SSL(Security Socket Layer) as a standardized secure transaction protocol and password authentication to perform online shopping and payment. The first one is for the case where online shopping mall is different from PG(Payment Gateway) and can be compared to PayPal-based payment methods, and the second one is for the case where online shopping mall is the same as PG and thus can be compared to Amazon-like methods. Two proposed protocols do not require users to perform any pre-registration process which is separate from an underlying shopping process, instead users can perform both shopping and payment into a single process in a convenient way. Also, users are asked to input a distinct payment password, which increases the level of security in the payment protocols. We believe that two proposed protocols can help readers to better understand the recent payment protocols that are suggested by various vendors, and to analyze the security of their payment protocols.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.1
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• pp.86-94
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• 2003

Certified e-mail system guarantees that recipient will get mail content if and only if mall originator receives a receipt. Unlike previous schemes, Optimistic protocols recently published generate a receipt when it meets the condition that the mail content can be accessed by recliner at any time. So originator cannot assure the delivery of e-mail although he can get a receipt. In this paper, we show some flaws in optimistic protocols and propose improved schemes using delivery deadline. Modified protocols guarantee proof-of-receipt and eliminate the problem mentioned above. Furthermore, proposed modification technique can be applicable to most optimistic protocols and is efficient in the sense that modified schemes do not increase the number of messages.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.553-556
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• 2014

최근 선박 전자 장비들이 디지털 인터페이스 표준을 위해 NMEA(National Marine Electronics Association)에서는 CAN Part B 표준 버스 프로토콜 기반의 네트워크 표준인 NMEA2000 표준을 개정하였다. NMEA2000는 네트워크상에서 PnP 기능을 가지는 멀티토커, 멀티리스너로서 네트워크 관리를 위한 서버가 필요 없는 멀티마스터의 실시간 제어 네트워크이다. 본 연구에서는 NMEA2000 기반의 선박 센서용 프로토콜 변환 알고리즘의 구현과 NMEA2000/CAN/Ethernet/RS422, RS485, RS232 포맷 변환 및 NMEA2000 기반 전용 케이블을 고려한 아날로그 데이터 모듈 외형 설계 및 개발을 목표로 한다. 본 연구를 통해 NMEA2000 핵심 기술의 개발과 적용을 통해 새로운 조선 IT 시장을 선점할 수 있을 것으로 기대된다.

• 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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.12C
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• pp.208-217
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• 2001

In mobile Internet environment, providing multicast requires much more complex mechanism comparing with the unicast Mobile IP routing protocol. This is because multicast datagrams are sent to a group address that do not belong to a specific network. The IETF Mobile IP suggested two approaches for mobile multicasting, namely remote subscription and hi-directional tunneling. In remote subscription, a mobile node may join a group via a local multicast router on the visited subnet. Therefore remote subscription may cause much datagram loss while reconstructing the delivery tee. In bi-directional tunneling, a mobile node may join a group via a hi-directional tunnel to its home agent. Bi-directional tunneling may suffer from inefficient routing. In this paper, we proposed a new mobile multicasting protocol, Mobile If Multicast using Local Broadcast(MIMLB) which can receive multicast datagrams as fast as possible and optimize routing path for multicast delivery. The MIMLB protocol uses hi-directional tunneling to receive multicast datagrams. And the MIMLB protocol can resolve datagram duplicated problem and optimize routing path by using local broadcast. Simulation results show that MIMLB reduces delivery path length and optimizes multicast routing path when a mobile nod? moves into a foreign network.

• KIPS Transactions on Computer and Communication Systems
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• v.9 no.8
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• pp.165-170
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• 2020

As the IoT (Internet of Things) era is activated, a lot of information including personal information is being transmitted through IoT devices. For information protection, it is important to perform cryptography communication, and it is required to use a lightweight security protocol due to performance limitations. Currently, most of the encryption methods used in the security protocol use RSA and ECC (Elliptic Curve Cryptography). However, if a high performance quantum computer is developed and the Shor algorithm is used, it can no longer be used because it can easily solve the stability problems based on the previous RSA and ECC. Therefore, in this paper, we designed a security protocol that is resistant to the computational power of quantum computers. The code-based crypto ROLLO, which is undergoing the NIST (National Institute of Standards and Technology) post quantum cryptography standardization, was used, and a hash and XOR computation with low computational consumption were used for mutual communication between IoT devices. Finally, a comparative analysis and safety analysis of the proposed protocol and the existing protocol were performed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11A
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• pp.1059-1067
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• 2006

AODV(Ad-hoc On-demand Distance Vector) routing protocol was devised for use of mobile nodes in Ad-hoc network. When we use the AODV routing protocol in Ad-hoc networks with high mobility, disturbance of optimized route path and link break occur. In order to solve the shortcomings, this paper proposes a new routing protocol in which new routing control messages are added to the existing AODV. The proposed protocol minimizes link break and transmission delay while is able to secure the optimized route path constantly in changes of network topology The performance of the proposed routing protocol was evaluated by using us2 network simulator. The actual Ad-hoc network test bed provides us the most reliable experimental data for Ad-hoc networks. In order to support this experimental environment, the dissertation also developed an efficient embedded system on which AODV routing protocol, NAT, Netfilter can run and other event message can be verified without declining efficiency. The correct operation of AODV routing protocol has been verified in both the Ad-hoc network test bed in which the embedded system was used, and Ad-hoc networks linked with Ethernet backbone network.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.3
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• pp.459-466
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• 2017

One of the most widely-used open source project; OpenSSL is a cryptography library that is used to secure most web sites, servers and clients. One can secure the communication with the Secure Socket Layer (SSL) or its successor, Transport Layer Security (TLS) protocols by using the OpenSSL library. Since cryptography protocols will be updated and enhanced in order to keep the system protected, the library was written in such a way that simplifies the integration of new cryptographic methods, especially for the symmetric cryptography protocols. However, it gets a lot more complicated in adding an asymmetric cryptography protocol and no guide can be found for the integration of the asymmetric cryptography protocol. In this paper, we explained the architecture of the OpenSSL library and provide a simple tutorial to modify the OpenSSL library in order to accommodate custom protocols of both symmetric and asymmetric cryptography.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.5
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• pp.906-912
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• 2012

A ship ad-hoc network (SANET) can provide ships with diverse multimedia services by replacing expensive satellite communications. While ITU-R M. 1842-1, standards for maritime VHF band digital communications, can be used as the specifications of physical layer for SANETs, no standards are specified for higher layers of SANETs. In this paper, we propose a ship ad-hoc communication (SAC) protocol for SANETs, based on medium access control (MAC) and routing protocols for terrestrial ad-hoc networks. SAC protocol is a cross-layer protocol which combines MAC and routing into one algorithm and considers maritime environments, including the existence of neighboring ships, the possibility of routing to a destination, and changing the communication mode in case of VHF channel failure.