• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.5
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• pp.2258-2274
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• 2020

In this paper we first propose a new cryptosystem based on our data hiding scheme (2,9,8) introduced in 2019 with high security, where encrypting and hiding are done at once, the ciphertext does not depend on the input image size as existing hybrid techniques of cryptography and steganography. We then exploit our automata approach presented in 2019 to design two algorithms for exact and approximate pattern matching on secret data encrypted by our cryptosystem. Theoretical analyses remark that these algorithms both have O(n) time complexity in the worst case, where for the approximate algorithm, we assume that it uses ⌈(1-ε)m)⌉ processors, where ε, m and n are the error of our string similarity measure and lengths of the pattern and secret data, respectively. In searchable encryption, our cryptosystem is used by users and our pattern matching algorithms are performed by cloud providers.

• Journal of Digital Convergence
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• v.15 no.4
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• pp.285-293
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• 2017

They are rapidly evolving malicious attacks on smart devices, and to timely protect the smart devices from these attacks has become a very important issue. In particular, smishing attack has emerged as one of the most important threats on the smartphone. In this paper, we propose the cloud service that can fundamentally protect the user from the risk of smishing attack. The proposed scheme provides cloud messaging service that can filter text messages including URLs in the user's smart device, view and manage them through a virtual machine provided by a cloud server. The existing techniques for preventing smshing attacks protect only malicious code of a known pattern and there is the possibility of error such as FP(False Positive) or FN(False Negative). However, since the proposed method automatically filters all text messages including URLs, storing, viewing, and managing them in their own storage space on the cloud server, it can completely block the installation of malwares(malicious codes) on the user's smart device through smishing attacks.

• Journal of Digital Convergence
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• v.11 no.12
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• pp.393-399
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• 2013

Recently, the quantity and type of data that is being processed in cloud environment are varied. A method for easy access in different network in a heterogeneous environment of big data stored in the device is required. This paper propose security management method for smoothly access to big data in other network environment conjunction with attribute information between big data and user. The proposed method has a high level of safety even if user-generated random bit signal is modulated. The proposed method is sufficient to deliver any number of bits the user to share information used to secure recognition. Also, the security awareness information bit sequence generated by a third party to avoid unnecessary exposure value by passing a hash chain of the user anonymity is to be guaranteed to receive.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.6
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• pp.83-94
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• 2016

Recent cloud, big data, there is a problem for the architectural security vulnerability to the server platforms of various fields such as artificial intelligence occurs consistently, but using the virtualization technology. In addition, most secure virtualization technology is known to be dependent on the type is limited and the platform provider. This paper presents a method for mutual authentication for secure data between multiple instances of a shared virtualized environment. The proposed method was designing a security architecture in consideration of the mutual authentication between multiple independent instances, and enhance the safety of a security protocol for sharing data by applying a key chain techniques. Performance analysis results and the existing security architecture demonstrated that protect each virtualized instances of the session and the other way, a compliance effectiveness for each instance of the mutual authentication process.

• Journal of Digital Convergence
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• v.11 no.11
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• pp.775-781
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• 2013

N-screen is a Service that can be provide for One Service Multi Device. If the network is changed or if the device is changed after authentication the device fits seamlessly send footage. Security threats that occur here have a problem with user authentication. In this paper proposes available in a multi-device the authentication system. Homomorphic Encryption Algorithm of authentication scheme used. Among the authentication mechanism that already exists is a simple and lightweight authentication mechanism. In addition, N-screen service that uses multiple devices is simple authentication process of the device. Review the results of proposed authentication protocol, encryption algorithm to process a small storage capacity and is easy to work in low processor. And was suitable for use with multiple devices.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.11
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• pp.469-478
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• 2019

Car-sharing services have been settled on as a new type of public transportation owing to their enhanced convenience, expanded awareness of practical consumption patterns, the inspiration for environmental conscientiousness, and the diffusion of smart phones following the economic crisis. With development of the market, many people have started using such services. However, security is still an issue. Damage is expected since IDs and passwords are required for log-in when renting and controlling the vehicles. The protocol suggested in this study uses bio-information, providing an optimized service, and convenient (but strong) authentication with various service-provider clouds registering car big data about users through brokers. If using the techniques suggested here, it is feasible to reduce the exposure of the bio-information, and to receive service from multiple service-provider clouds through one particular broker. In addition, the proposed protocol reduces public key operations and session key storage by 20% on mobile devices, compared to existing car-sharing platforms, and because it provides convenient, but strong, authentication (and therefore constitutes a secure channel), it is possible to proceed with secure communications. It is anticipated that the techniques suggested in this study will enhance secure communications and user convenience in the future car-sharing-service cloud environment.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.4
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• pp.1404-1423
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• 2015

In smart grid, electricity consumption data may be handed over to a third party for various purposes. While government regulations and industry compliance prevent utility companies from improper or illegal sharing of their customers' electricity consumption data, there are some scenarios where it can be very useful. For example, it allows the consumers' data to be shared among various energy resources so the energy resources are able to analyze the data and adjust their operation to the actual power demand. However, it is crucial to protect sensitive electricity consumption data during the sharing process. In this paper, we propose a fine-grained access control scheme (FAC) with efficient attribute revocation and policy updating in smart grid. Specifically, by introducing the concept of Third-party Auditor (TPA), the proposed FAC achieves efficient attribute revocation. Also, we design an efficient policy updating algorithm by outsourcing the computational task to a cloud server. Moreover, we give security analysis and conduct experiments to demonstrate that the FAC is both secure and efficient compared with existing ABE-based approaches.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.11a
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• pp.465-467
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• 2020

최근 정보 기술의 발전으로 클라우드 컴퓨팅은 개개인에게 편의성을 제공하도록 기능하지만, 실생활에서 디지털 정보의 의존성을 높이게 되었다. 클라우드 컴퓨팅은 실시간으로 다양한 정보를 교환함으로써 다양한 어플리케이션 서비스를 제공한다. 특히, 사용자가 가지고 있는 정보들을 로컬 서버에 관리하기 어려운 문제를 해결하기 위해 아웃소싱 클라우드 스토리지 서비스를 이용하여 해결할 수 있다. 그러나, 사용자의 데이터를 외부 클라우드 서버에 업로드하여 저장하게 되면, 클라우드 서비스 제공자로 인한 프라이버시 문제가 발생할 수 있다. 최근, 클라우드 서버에서 발생할 수 있는 프라이버시 문제를 해결하기 위해서 사용자의 데이터를 암호화하여 클라우드 서비스 제공자로부터 사용자의 정보를 보호하는 연구가 진행되고 있다. 하지만 이 연구는 시간이 지남에 따라 암호화가 복호화될 수 있으며, 특히 클라우드 서버에서 Offline Bruteforce 공격이 발생할 수 있다. 본 논문에서는 클라우드 환경에서 사용자의 개인정보를 보호하기 위한 기존 연구의 한계점을 분석한다. 기존 연구 분석을 통해 개인정보 보호를 위한 요구사항을 도출하고, 이를 기반으로 안전한 분산 데이터 관리 기법에 대해 고찰한다.

• Journal of Internet Computing and Services
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• v.18 no.2
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• pp.21-30
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• 2017

IoT(Internet of Things) can enable networking and computing using any devices is rapidly proliferated. In the existing IoT environment, bottlenecks and service delays can occur because it processes data and provides services to users using central processing based on Cloud. For this reason, Edge Computing processes data directly in IoT nodes and networks to provide the services to the users has attracted attention. Also, numerous researchers have been attracted to intelligent service efficiently based on Edge Computing. In this paper, expert system-based context awareness scheme for Edge Computing in IoT environment is proposed. The proposed scheme can provide customized services to the users using context awareness and process data in real-time using the expert system based on efficient cooperations of resource limited IoT nodes. The context awareness services can be modified by the users according to the usage purpose. The three service modes in the security system based on smart home are used to test the proposed scheme and the stability of the proposed scheme is proven by a comparison of the resource consumptions of the servers between the proposed scheme and the PC-based expert system.