• KIPS Transactions on Computer and Communication Systems
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• v.9 no.12
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• pp.307-314
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• 2020

The video surveillance service is being widely deployed around our lives and the service stores sensitive data such as video streams in the cloud over the Internet or the centralized data store in an on-premise environment. The main concerning of these services is that the user should trust the service provider how secure the video or data is stored and handled without any concrete evidence. In this paper, we proposed the approach to protecting video by PKI (public key infrastructure) with a blockchain network. The video is encrypted by a symmetric key, then the key is shared through a blockchain network with taking advantage of the PKI mechanism. Therefore, the user can ensure the sensitive data is always kept secure and traceable in its lifecycle.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.5
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• pp.779-790
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• 2022

Fuzzy extractor is a biometric encryption that generates keys from biometric data where input values are not always the same due to the noisy data, and performs authentication securely without exposing biometric information. However, if a user registers biometric data on multiple servers, various attacks on helper data which is a public information used to extract keys during the authentication process of the fuzzy extractor can expose the keys. Therefore many studies have been conducted on reusable fuzzy extractors that are secure to register biometric data of the same person on multiple servers. But as the key length increases, the studies presented so far have gradually increased the number of key recovery processes, making it inefficient and difficult to utilize in security systems. In this paper, we design an efficient and reusable fuzzy extractor based on LWE with the same or similar number of times of the authentication process even if the key length is increased, and show that the proposed algorithm is reusably-secure defined by Apon et al.[5].

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.7
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• pp.540-544
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• 2007

Researches on Sensor Network has become much more active and is currently being applied to many different fields. However since sensor network is limited to only collecting and reporting information regarding a certain event, and requires human intervention with that given information, it is often difficult to react to an event or situation immediately and proactively. To overcome this kind of limitation, Wireless Sensor and Actor Networks (WSANs) with immediate-response Actor Nodes has been proposed which adds greater mobility and activity to exisiting sensor networks. Although WSANs shares many common grounds with sensor networks, it is difficult to apply exisiting security technologies due to the fact that WSAN contains Actor Nodes that are resource-independent and mobile. This research therefore seeks to demonstrate ways to provide security, integrity and authentication services for WSAN's secure operation, by separating networks into hierarchcial structure by each node's abilities and providing different encryption key-based secure protocols for each level of hierarchy: Pair-wise Key, Node Key, and Region Key for sensor levels, and Public Key for actor levels.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.5
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• pp.1099-1112
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• 2018

The field of post-quantum cryptography (PQC) is an active area of research as cryptographers look for public-key cryptosystems that can resist quantum adversaries. Among those categories in PQC, code-based cryptosystem provides high security along with efficiency. Recent works on code-based cryptosystems focus on the side-channel resistant implementation since previous works have indicated the possible side-channel vulnerabilities on existing algorithms. In this paper, we recovered the secret key in HyMES(Hybrid McEliece Scheme) using a single power consumption trace. HyMES is a variant of McEliece cryptosystem that provides smaller keys and faster encryption and decryption speed. During the decryption, the algorithm computes the parity-check matrix which is required when computing the syndrome. We analyzed HyMES using the fact that the joint distributions of nonlinear functions used in this process depend on the secret key. To the best of our knowledge, we were the first to propose the side-channel analysis based on joint distributions of leakages on public-key cryptosystem.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.6
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• pp.205-212
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• 2015

SSH provides a secure, encrypted communication channel between two end point systems using public key encryption. But SSH brute force attack is one of the most significant attacks. This kind of attack aims to login to the SSH server by continually guessing a large number of user account and password combinations. In this paper, we analyze logs of SSH brute force attacks in 2014 and propose a failed-log based detection mechanism in high performance computing service environment.

• IEIE Transactions on Smart Processing and Computing
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• v.2 no.2
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• pp.57-66
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• 2013

Wireless Sensor Networks consist of small, inexpensive, low-powered sensor nodes that communicate with each other. To achieve a low communication cost in a resource constrained network, a novel concept of signcryption has been applied for secure communication. Signcryption enables a user to perform a digital signature for providing authenticity and public key encryption for providing message confidentiality simultaneously in a single logical step with a lower cost than that of the sign-then-encrypt approach. Ring signcryption maintains the signer's privacy, which is lacking in normal signcryption schemes. Signcryption can provide confidentiality and authenticity without revealing the user's identity of the ring. This paper presents the security notions and an evaluation of an ID-based ring signcryption scheme for wireless sensor networks. The scheme has been proven to be better than the existing schemes. The proposed scheme was found to be secure against adaptive chosen ciphertext ring attacks (IND-IDRSC-CCA2) and secure against an existential forgery for adaptive chosen message attacks (EF-IDRSC-ACMA). The proposed scheme was found to be more efficient than scheme for Wireless Sensor Networks reported by Qi. et al. based on the running time and energy consumption.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.2
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• pp.411-420
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• 1999

The topic of electronic commerce is a hot issue in computer technology. There are many kinds of risks associated with electronic commerce which performs financial transactions by exchanging electronic information over public networks. Therefore, security factors such as confidentiality, integrity, authentication and non-repudiation should be required to construct secure electronic commerce systems. In this paper, the credit card-based payment protocol applying dual signature is presented. It provides payment information to the bank a cardholder pays to, but conceals ordering information. It also offers ordering information to a merchant, but hides payment information including the card number. Thus, cardholder's private information can be protected. In order to accomplish this, dual signature is performed employing both symmetric method utilizing cardholder's secret number as an encryption key and asymmetric method.

• Journal of the Korea Computer Industry Society
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• v.4 no.4
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• pp.625-632
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• 2003

We are view of the information on VPN(Virtual private Network) into each difference layer protocol. network on mutuality exchanged of information is importance of the confidentiality and Integrity. But it is presented problems about compatability and availability between variable equipment as several protocol. hence, it was achieved of the transmission through encryption and authentication of information, although there is secured an intended attack from the third intruder. so tunneling VPN system on achieving, each layer position transmit of mutuality exchanged. This study will investigate the codification and certified security status when layer2 and layer 3 informations are each transmitted using protocol with integrity Public Key. In addition, we will using protocol and the performance analysis difference between layers and layers.

• Journal of the military operations research society of Korea
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• v.33 no.2
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• pp.115-127
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• 2007

The army developed the ATCIS(Army Tactical Command Information System) for the battlefield information system with share the command control information through the realtime. The using the public key and the encryption equipment in the ATCIS is enough to the confidentiality, integrity. but, it is vulnerable about the availability with the zero day attack. In this paper, we implement the worm propagation simulation on the ATCIS infrastructure through the modelling on the ATCIS operation environment. We propose the countermeasures based on the results from the simulation.

• Annual Conference of KIPS
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• 2003.11c
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• pp.2021-2024
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• 2003

Information security is becoming a more important factor in distribution of digital contents. Generally, illegal facsimile of high-quality multimedia products such as DVDs, MP3s and AACs is possible without damaging quality. Thus, the illegal distribution of duplicated contents on the Web is causing digital content providers great economic loss. Therefore, a study of security and efficient distribution of digital contents is required. The most important issues in the design of a digital content distribution system are user convenience, execution speed and security. In this study, we designed a digital contents distribution system that uses web caching technology and encryption/decryption techniques in hierarchical structures. We propose a digital content distribution system that improves user convenience, security and execution speed. The superior performance of the proposed system has been proven in the tests. The results of experiment show that the developed system has improved the security of DC without decreasing process speed.