• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.6
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• pp.2074-2093
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• 2022

RSA is known as one of the best techniques for securing secret information across an unsecured network. The private key which is one of private parameters is the aim for attackers. However, it is exceedingly impossible to derive this value without disclosing all unknown parameters. In fact, many methods to recover the private key were proposed, the performance of each algorithm is acceptable for the different cases. For example, Wiener's attack is extremely efficient when the private key is very small. On the other hand, Fermat's factoring can quickly break RSA when the difference between two large prime factors of the modulus is relatively small. In general, if all private parameters are not disclosed, attackers will be able to confirm that the private key is unquestionably inside the scope [3, n - 2], where n is the modulus. However, this scope has already been reduced by increasing the greatest lower bound to [d_il, n - 2], where d_il ≥ 3. The aim of this paper is to decrease the least upper bound to narrow the scope that the private key will remain within this boundary. After finishing the proposed method, the new scope of the private key can be allocated as [d_il, d_ir], where d_ir ≤ n - 2. In fact, if the private key is extremely close to the new greatest lower bound, it can be retrieved quickly by performing a brute force attack, in which d_ir is decreased until it is equal to the private key. The experimental results indicate that the proposed method is extremely effective when the difference between prime factors is close to each other and one of two following requirement holds: the first condition is that the multiplier of Euler totient function is very close to the public key's small value whereas the second condition is that the public key should be large whenever the multiplier is far enough.

• Convergence Security Journal
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• v.16 no.4
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• pp.17-24
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• 2016

Many companies and organizations are building a mobile office environment using the LTE network, the national disaster network and Air Force LTE network are built for public safety and national defense. However the recent threats on information security have been evolving from information leakage to DDoS attacks to neutralize the service. Especially, the type of device such as Smart phones, smart pad, tablet PC, and the numbers are growing exponentially and As performance of mobile device and speed of line develop rapidly, DDoS attacks in the mobile environment is becoming a threat. So far, universal countermeasure to DDoS attacks has been interception the network and server step, Yet problem regarding DDoS attack traffic on mobile network and expenditure of network resources still remains. Therefore, this paper analyzes the traffic type distributed in the private mobile network such as the National Disaster Network, and Air Force LTE network in order to preemptively detect DDoS attacks on terminal step. However, as direct analysis on traffic distributed in the National Disaster Network, and Air Force LTE network is restricted, transmission traffics in Minecraft and uploading video file upload which exhibit similar traffic information are analyzed in time series, thereby verifing its effectiveness through establishment of DDoS attacks standard in mobile network and application that detects and protects DDoS attacks

• Journal of the Society of Disaster Information
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• v.12 no.4
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• pp.321-328
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• 2016

In this study, the characteristics and the status of disaster management in rural area were analyzed. Through this study, we tried to find ways to cooperate with public and private organizations to manage disaster in rural areas. In order to understand the current state of disaster management in rural areas, we surveyed the residents and disaster management officials of local governments. As a result of the survey, both public servants and residents answered that it is difficult for residents to participate in disaster management. This is due to lack of time due to agriculture as the main business. The SWOT analysis and strategy of rural disaster management were derived through the analysis of these surveys. In addition, five types of disaster management network and two types of operation were proposed. Therefore, it is necessary to establish the management plan of the rural disaster management public-private network in the rural area. Further research is needed in depth on each of the operational measures in the future.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.8
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• pp.860-872
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• 2013

In this paper, reasonable and effective building strategies of PPDR network is presented through investigating and analysing current policies for PPDR network of Korea and foreign countries. The research result shows that it is necessary PPDR network is designed and implemented considering currently transient status in aspects of PPDR-related technical roadmaps and existing PPDR networks. Also, in the transient period of more than 5 years, mobile broadband- based private PPDR network should be builded and it should be complemented by some commercial networks such as TRS or other mobile broadband networks.

• IEIE Transactions on Smart Processing and Computing
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• v.5 no.2
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• pp.94-99
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• 2016

Application layer attacks have for years posed an ever-serious threat to network security, since they always come after a technically legitimate connection has been established. In recent years, cyber criminals have turned to fully exploiting the web as a medium of communication to launch a variety of forbidden or illicit activities by spreading malicious automated software (auto-ware) such as adware, spyware, or bots. When this malicious auto-ware infects a network, it will act like a robot, mimic normal behavior of web access, and bypass the network firewall or intrusion detection system. Besides that, in a private and large network, with huge Hypertext Transfer Protocol (HTTP) traffic generated each day, communication behavior identification and classification of auto-ware is a challenge. In this paper, based on a previous study, analysis of auto-ware communication behavior, and with the addition of new features, a method for classification of HTTP auto-ware communication is proposed. For that, a Not Only Structured Query Language (NoSQL) database is applied to handle large volumes of unstructured HTTP requests captured every day. The method is tested with real HTTP traffic data collected through a proxy server of a private network, providing good results in the classification and detection of suspicious auto-ware web access.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.6
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• pp.526-532
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• 2004

The insufficiency on IP address cause to develope a new internet protocol, IPv6 that the length of address field is expanded. But there are actually many problems on applying and operating this standard for internet. Though NAT(Network Address Translation) is instead of it, NAT has the characteristics that is not allowed to access from outside. This is a big merit in security but a week point because the access from outside should be allowed when a small organization operate web sever or mail server. Therefore, this paper proposes the expanded NAT which can solve such problems as modifying the table of NAT. Furthermore, the function of existing VPN(Virtual Private Network) will be acceptable partly through such a method that provide the linkage among VPNs.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.4
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• pp.39-46
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• 2011

This study is conducted to examine the optimal integrated security policy based on network in case of attacks by implementing unique security policies of various network security equipments as an algorithm within one system. To this end, the policies conduct the experiment to implement the optimal security system through the process of mutually integrating the unique defense policy of Firewall, VPN(Virtual Private Network), IDS(Intrusion Detection System), and IPS(Intrusion Prevention System). In addition, this study is meaningful in that it designs integrated mechanism for rapid detection of system load caused by establishment of the security policy and rapid and efficient defense and secures basic network infrastructure implementation.

• Journal of Aerospace System Engineering
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• v.13 no.4
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• pp.1-9
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• 2019

Integration of satellites with diverse missions, such as broadcast-communication, earth, meteorologicaland marine observations, and navigation, is vulnerable. The problems of the currently constructed ground station network were analyzed by constructing the test environment. Based on this, we designed a network that was capable of operating multiple satellites by one ground station. In addition, we proposed an interface and network configuration method with domestic and foreign ground stations. The network linking the domestic and foreign ground stations was composed of KREONET (Korea Research Environment Open Network) and GLORIAD (Global Ring Network for Advanced Application Development) of the KISTI(Korea Institute of Science and Technology Information). The internal network consists of VPN (Virtual Private Network), DMZ(De-Militarized Zone), and 1-way USB and so forth. By constructing the network by using the proposed method, harmful data, such as virus inflow and infection, can be blocked.

• Journal of the Korean Society of Systems Engineering
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• v.9 no.2
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• pp.91-97
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• 2013

Recently, the Korean Railroad have been operating separately by Korea Rail Network and the Korail since 2005. In addition, because of the lack of government's social overhead capital, New railway projects have been built and operated by private investors which don't have railway operating experience. Therefore, systems engineering management is needed from the initial planning stage to the construction and the opening. In this paper, structural features were considered according to the separation of Daegok-Sosa-Wonsi Private Finance Initiative (Daegok-Sosa, Sosa-wonsi) and the operating agency's unification(Daegok - Sosa business operations). And based on the domestic system engineering applications, System-Engineering Implementation was studied.

• Journal of Information Processing Systems
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• v.17 no.2
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• pp.284-296
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• 2021

The cloud has already become the core infrastructure of information systems, and government institutions are rapidly migrating information systems to the cloud. Government institutions in several countries use private clouds in their closed networks. However, because of the advantages of public clouds over private clouds, the demand for public clouds is increasing, and government institutions are expected to gradually switch to public clouds. When all data from government institutions are managed in the public cloud, the biggest concern for government institutions is the leakage of confidential data. The public-private-partnership (PPP) cloud provides a solution to this problem. PPP cloud is a form participation in a public cloud infrastructure and the building of a closed network data center. The PPP cloud prevents confidential data leakage and leverages the benefits of the public cloud to build a cloud quickly and easily maintain the cloud. In this paper, based on the case of the PPP cloud applied to the Korean government, the concept, architecture, operation model, and contract method of the PPP cloud are presented.