• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2003.12a
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• pp.669-685
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• 2003

Nowadays mobile phones and PDAs are part and parcel of our lives. By carrying a portable mobile device with us all the time we are already living in partial Pervasive Computing Environment (PCE) that is waiting to be exploited very soon. One of the advantages of pervasive computing is that it strongly supports the deployment of Location-Based Service(s) (LBSs). In PCE, there would be many competitive service providers (SPs) trying to sell different or similar LBSs to users. In order to reserve a particular service, it becomes very difficult for a low-computing and resource-poor mobile device to handle many such SPs at a time, and to identify and securely communicate with only genuine ones. Our paper establishes a convincing trust model through which secure job delegation is accomplished. Secure Job delegation and cost effective cryptographic techniques largely help in reducing the burden on the mobile device to securely communicate with trusted SPs. Our protocol also provides users privacy protection, replay protection, entity authentication, and message authentication, integrity, and confidentiality. This paper explains our protocol by suggesting one of the LBSs namely“Secure Automated Taxi Calling Service”.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.11
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• pp.5610-5624
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• 2017

A novel scheme based on polarization modulation and the weighted fractional Fourier transform (PM-WFRFT) is proposed in this paper to enhance the physical layer security of dual-polarized satellite systems. This scheme utilizes the amplitude and phase of the carrier as information-bearing parameters to transmit the normal signal and conceals the confidential information in the carrier's polarization state (PS). After being processed by WFRFT, the characteristics of the transmit signal (including amplitude, phase and polarization state) vary randomly and in nearly Gaussian distribution. This makes the signal very difficult for an eavesdropper to recognize or capture. The WFRFT parameter is also encrypted by a pseudo-random sequence and updated in real time, which enhances its anti-interception performance. Furthermore, to prevent the polarization-based impairment to PM-WFRFT caused by depolarization in the wireless channel, two components of the polarized signal are transmitted respectively in two symbol periods; this prevents any mutual interference between the two orthogonally polarized components. Demodulation performance in the system was also assessed, then the proposed scheme was validated with a simulated dual-polarized satellite system.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11b
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• pp.849-852
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• 2002

무선 PKI 환경에서는 단말기의 한계나 무선 환경이라는 제약 때문에 유선 PKI 환경에서 제공되는 다양한 서비스를 받기 위해 여러 가지 기술이 요구되며, 이를 위해 많은 기술 규격들이 개발되어 표준화가 진행 중에 있다. 본 논문에서는 현재 표준화가 완료된 무선 PKI 기술 표준과 표준화가 진행중인 무선 PKI 기술 규격에 대해 알아보고 이를 이용하여 제공되고 있는 서비스에 대해 알아본다. 또한, 향후에 무선 PKI 기반에서 제공될 수 있는 서비스와 무선 환경의 제약사항을 개선할 수 있는 방안을 제안한다.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.30 no.10
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• pp.46-52
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• 2012

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.25 no.9
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• pp.81-88
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• 2007

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.5
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• pp.137-145
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• 2003

Nowadays, people can communicate with each other on any time at my place by development of wireless communications. But, the openness of mobile communications Poses serious security threats and the security is necessary on mobile communications to support the secure communication channel. The most commonly method is stream cipher for mobile communications. Generally, this stream cipher is implemented by LFSR(Linear Feedback Shift Register). On this paper proposes the modified mechanism of the S box is usually used in block cipher to advance security og the stream cipher and this mechanism is the modified three one in consideration og the randomness. Generally, S box that is function with nonlinear property makes data more strong by attack. The randomness test of the proposed algorithm is used Ent Pseudorandom Number Sequence Test Program and by the test result it proves that it has better randomness and serial correlation value than the based stream cipher on respective test.

• Proceedings of the KAIS Fall Conference
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• 2003.11a
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• pp.155-162
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• 2003

Today's network consists of a large number of routers and servers running a variety of applications. Policy-based network provides a means by which the management process can be simplified and largely automated. In this paper we build a foundation of policy-based network modeling and simulation environment. The procedure and structure for the induction of policy rules from vulnerabilities stored in SVDB (Simulation based Vulnerability Data Base) are developed. The structure also transforms the policy rules into PCIM (Policy Core Information Model). The effect on a particular policy can be tested and analyzed through the simulation with the PCIMs and SVDB.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.1
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• pp.87-93
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• 2016

In this paper, we propose a new method to enhance an android security by exploiting a selective management of application permission. To that purpose, we analyze behavior of the current android security, via which we draw out possible vulnerabilities. After that, we develop a tool to implement the selective management of the application permission, witch has a function to give a permission selectively for the application when we install a new application. Via experiment we show validity of the developed tool in solving the drawn vulnerability in the current android security.

• Journal of Communications and Networks
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• v.11 no.6
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• pp.634-644
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• 2009

A diversity of wireless networks, with rapidly evolving wireless technology, are currently in service. Due to their innate physical layer vulnerability, wireless networks require enhanced security components. WLAN, WiBro, and UMTS have defined proper security components that meet standard security requirements. Extensive research has been conducted to enhance the security of individual wireless platforms, and we now have meaningful results at hand. However, with the advent of ubiquitous service, new horizontal platform service models with vertical crosslayer security are expected to be proposed. Research on synchronized security service and interoperability in a heterogeneous environment must be conducted. In heterogeneous environments, to design the balanced security components, quantitative evaluation model of security policy in wireless networks is required. To design appropriate evaluation method of security policies in heterogeneous wireless networks, we formalize the security properties in wireless networks. As the benefit of security protocols is indicated by the quality of protection (QoP), we improve the QoP model and evaluate hybrid security policy in heterogeneous wireless networks by applying to the QoP model. Deriving relative indicators from the positive impact of security points, and using these indicators to quantify a total reward function, this paper will help to assure the appropriate benchmark for combined security components in wireless networks.

• Journal of the Korea Society of Computer and Information
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• v.8 no.3
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• pp.138-143
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• 2003

With information communications and network environments merged wire/wireless networks are generalized. In this viewpoint, WAP is used by communication protocol for the data communication in the field of wireless environment. WTLS developed for the secure communications optimize TLS adapted wireless environment in the TCP/IP internet protocol. But WTLS denote WAP security problem, end-to-end problem, and power consumption, etc. Therefore in this paper we proposed WTLS cryptographic algorithm eliminated WTLS disadvantages. Proposed algorithm solved power consumption, calculated complexity, and security problems because it is not unique but hybrid form.