• The Journal of Information Systems
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• v.23 no.1
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• pp.225-246
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• 2014

With the recent establishment of a ubiquitous environment and the paradigm shift to a smart society, the use of mobile devices, such as smart phones and tablet PCs, has become widespread. Thus, the trend is gradually shifting from using Web-based Instant Messenger to using Mobile-based Instant Messenger. Mobile Instant Messenger refers to a service that allows instant messaging as well as data sending and receiving between individuals with exclusive application programs(mobile Apps), which can be used in portable devices-such as smart phones-with wireless Internet access. Korea's portal sites, telecommunication companies, and even big companies have all rushed into the MIM market to join the competition. The reason so many companies are showing interest in the MIM business is because it is rising as a core platform to substitute portal sites in the mobile society, and MIM is perceived as the best means to attract and secure users. The intention to reuse or use continually was considered an important factor in maintaining a dominant position amidst such fierce competition, and consequently, most research thus far has reflected such thought. However, the frequent or long-term use of a system alone cannot indicate the definite success of the system, nor guarantee its dominant position in the market. On the contrary, MIM dependence, which goes beyond simple repetitive use and indicates a state where users actually or emotionally depend on a specific system, can better explain the user action. However, not much research has been conducted on dependence. The research results showed that lively message, concise message, message responsiveness, and social belonging significantly affected perceived usefulness. Message responsiveness, Link, and social belonging significantly affected flow. Flow significantly affected MIM dependence, and perceived usefulness did not affect MIM dependence. This study has proven that lively message, concise message, message responsiveness, Link, social belonging and perceived usefulness are important antecedents and mediating factors of MIM dependence. Moreover, this study is significant in that it explains the overall process of MIM dependence, and expands on the variety and scope of research that can be applied to MIM-related studies.

• Journal of Convergence for Information Technology
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• v.7 no.6
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• pp.97-102
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• 2017

In this paper, we have interested in cooperative intelligent transport system and autonomous driving system, and focused on analysis of the characteristics of Cooperative Awareness Message (CAM) and Decentralized Environmental Notification Basis Service (DENM) message, which is key delivery message among cooperative intelligent transport system (C-ITS) characteristics for research objectivity. For research method, we also described V2X communication, and also analyzed the security certificate and header structure of CAM and DENM messages. We described CAM message, which is a message informing the position and status of the vehicle. And the DENM message is presented a message informing an event such as a vehicle accident, and analysis security communication, which is supported services. According to standard analysis result, 186 bits or 275 bits are used. In addition to the security header and the certificate format used for vehicle communication, we have gained the certificate verification procedure for vehicles and PKI characteristics for vehicles. Also We derived the characteristics and transmission capability of the security synchronization pattern required for V2X secure communication. Therefore when it is considered for communication service of DENM and CAM in the C-ITS environment, this paper may be meaningful result.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.4
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• pp.41-52
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• 2010

Message authentication is an essential security element in vehicular ad-hoc network(VANET). For a secure message authentication, integrity, availability, privacy preserving skill, and also efficiency in various environment should be provided. RAISE scheme has been proposed to provide efficient message authentication in the environment crowded with lots of vehicles and generally considered to be hard to provide efficiency. However, as the number of vehicles communicating in the area increases, the overhead is also incurred in proportion to the number of vehicles so that it still needs to be reduced, and the scheme is vulnerable to some attacks. In this paper, to make up for the vulnerabilities in dense vehicular communication network, we propose a more secure and efficient scheme using a process that RSU(Road Side Unit) transmits the messages of neighbor vehicles at once with Bloom Filter, and timestamp to protect against replay attack. Moreover, by adding a handover function to the scheme, we simplify the authentication process as omitting the unnecessary key-exchange process when a vehicle moves to other area. And we confirm the safety and efficiency of the scheme by simulating the false positive probability and calculating the traffic.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.2
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• pp.345-358
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• 2016

In this paper, we present a security tool which called Digital Legal Seal. The Digital Legal Seal scans a barcode on a paper and print it with the tag generated by Hash-based Message Authentication Code(HMAC) in text format on a display device. The result of HMAC can be used for user authentication or secure message transmission on both online and offline. We examine not only how the Digital Legal Seal can make up the weak points of security card and OTP (One Time Password), but also the possibility of reducing the forgery of promissory note on offline.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.10
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• pp.1969-1975
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• 2015

The Internet of Things (IoT), in which resource constrained devices communicate with each other, requires a lightweight security protocol. In this paper, we propose a new message authentication scheme using a hash tree for lightweight message authentication in the Datagram Transport Layer Security (DTLS) protocol. The proposed scheme provides lightweight secure operations compared with those of the DTLS protocol. Besides, it provides more suitable performance than the DTLS protocol for an IoT environment, thanks to the reduced use of message authentication code.

• Convergence Security Journal
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• v.3 no.3
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• pp.1-6
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• 2003

The IPv6 was suggested as an ultimate solution of problems that IPv4 protocol maintains limitations to apply to new technology of data service and the lack of IPv4 address space. So it is expected to transfer IPv4 to IPv6 gradually. In the Ipv6 environment, it is easier to apply security policies and transmits a secure packet applied the security policies, with the content in the Header itself. By this reason, this paper describes about the implementation of DHCPv6 server to perform a connection of IPv6 network and IPv4 network, and the application of secure packet with the security policies for clients. Further, it performs the process of the massages inside the DHCPv6 server to be used in the IPv6 environment in the future.

• Journal of KIISE:Computing Practices and Letters
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• v.11 no.6
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• pp.531-537
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• 2005

The Tunnel Broker is to provide dedicated servers and to automatically manage tunnel requests coming from the users. This approach is useful to stimulate the growth of IPv6 interconnected hosts and to provide easy access to their IPv6 networks. However, the existing tunnel broker is vulnerable to attacks of malicious users about network resources and services. Therefore, to solve the secure problem of tunnel broker, this paper presents secure IPv6 tunnel broker based on TSP(Tunnel Setup Protocol). The clients and the tunnel broker are communicated based on SHTTP(Secure HTTP) and the XML message of plain text is converted to XML signature by encryption and decryption. finally, Clients and tunnel server use the IPsec method to protect the important information.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.6
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• pp.3280-3298
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• 2019

Vehicular ad-hoc networks (VANETs) have become increasingly significant in intelligent transportation systems, they play a great role in improving traffic safety and efficiency. In the deployment of intelligent VANETs, intelligent vehicles can efficiently exchange important or urgent traffic information and make driving decisions. Meanwhile, secure data communication and vehicle's identity privacy have been highlighted. To cope with these security issues, in this paper, we construct an efficient anonymous authentication scheme with secure communication in intelligent VANETs. Combing the ElGamal encryption technique with a modified Schnorr signature technique, the proposed scheme provides secure anonymous authentication process for encrypted message in the vehicle-to-infrastructure communication model, and achieves identity privacy, forward security, and reply attack resistance simultaneously. Moreover, except the trusted authority (TA), any outside entity cannot trace the real identity of an intelligent vehicle. The proposed scheme is designed on an identity-based system, which can remove the costs of establishing public key infrastructure (PKI) and certificates management. Compared with existing authentication schemes, the proposed scheme is much more practical in intelligent VANETs.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1996.11a
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• pp.326-335
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• 1996

In this paper, we quantify the tradeoff between security and performance in secure data communication systems based on the queueing theory, and propose the optimization methods, such as the preprocessing, a message segmentation, compression, integration of compression and encryption and integration of user authentication and access control, which are able to reduce the delay induced by the security mechanisms and protocols. Moreover, we analyze the average delay for the secure data communication systems through the computer simulations, which are modeled by M/M/1, M/E$_2$/1 and M/H$_2$/1 queueing systems, respectively. We consider the DES, RSA digital signature and the combination of IDEA and RSA as security mechanisms for applying security services.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1995.11a
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• pp.200-210
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• 1995

Almost all hash functions suggested up till now provide security by using complicated operations on fixed size blocks, but still the security isn't guaranteed mathematically. The difficulty of making a secure hash function lies in the collision freeness, and this can be obtained from permutation polynomials. If a permutation polynomial has the property of one-wayness, it is suitable for a hash function. We have chosen Dickson polynomial for our hash algorithm, which is a kind of permutation polynomials. When certain conditions are satisfied, a Dickson polynomial has the property of one-wayness, which makes the resulting hash code mathematically secure. In this paper, a message digest algorithm will be designed using Dickson polynomial.