• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.217-219
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• 2021

With the development of ICT, the amount of data increases, and the technology of storing and processing becomes important. In this study, we study real-time file copy leakage prevention system to prevent leakage of important data in enterprises, public places, etc. As a research method, we propose a system that detects events in real time to prevent data leakage after analyzing data leakage cases and problems. The file leakage prevention system compares and analyzes with the existing EDLP system, and the proposed system reduces load and detects events. Future research requires research on the prevention of leaks through networks and various channels.

• The KIPS Transactions:PartC
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• v.16C no.6
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• pp.773-782
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• 2009

A DHT(Distributed Hash Table) based P2P is a method to overcome disadvantages of the existing unstructured P2P method. If a DHT algorithm is used, it can do a fast data search and maintain search efficiency independent of the number of peer. The peers in the DHT method send messages periodically to keep the routing table updated. In a mobile environment, the peers in the DHT method should send messages more frequently to keep the routing table updated and reduce the failure of a request. Therefore, this results in increase of network traffic. In our previous research, we proposed a method to reduce the update load of the routing table in the existing Chord by updating it in a reactive way, but the reactive method had a disadvantage to generate more traffic than the existing Chord if the number of requests per second becomes large. In this paper, we propose an adaptive method of routing table update to reduce the network traffic. In the proposed method, we apply different routing table update method according to the number of request message per second. If the number of request message per second is smaller than some threshold, we apply the reactive method. Otherwsie, we apply the existing Chord method. We perform experiments using Chord simulator (I3) made by UC Berkeley. The experimental results show the performance improvement of the proposed method compared to the existing methods.

• The KIPS Transactions:PartC
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• v.16C no.6
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• pp.761-772
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• 2009

A DHT(Distributed Hash Table) based P2P is a method to overcome disadvantages of the existing unstructured P2P method. If a DHT algorithm is used, it can do a fast data search and maintain search efficiency independent of the number of peer. The peers in the DHT method send messages periodically to keep the routing table updated. In a mobile environment, the peers in the DHT method should send messages more frequently to keep the routing table updated and reduce the failure of a request. Therefore, this results in increase of network traffic. In our previous research, we proposed a method to reduce the update load of the routing table in the existing Chord by updating it in a reactive way, but the reactive method had a disadvantage to generate more traffic than the existing Chord if the number of requests per second becomes large. In this paper, we propose an adaptive method of routing table update to reduce the network traffic. In the proposed method, we apply different routing table update method according to the number of request message per second. If the number of request message per second is smaller than some threshold, we apply the reactive method. Otherwsie, we apply the existing Chord method. We perform experiments using Chord simulator (I3) made by UC Berkeley. The experimental results show the performance improvement of the proposed method compared to the existing methods.

• Journal of Convergence for Information Technology
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• v.8 no.3
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• pp.79-84
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• 2018

Cloud services are readily available through a variety of media, attracting a lot of attention from users. However, there are various security damages that abuse the privacy of users who use cloud services, so there is not enough technology to prevent them. In this paper, we propose a protection model to safeguard user's privacy in a cloud environment so as not to illegally exploit user's privacy. The proposed model randomly manages the user's signature to strengthen the role of the middle manager and the cloud server. In the proposed model, the user's privacy information is provided illegally by the cloud server to the user through the security function and the user signature. Also, the signature of the user can be safely used by bundling the random number of the multiplication group and the one-way hash function into the hash chain to protect the user's privacy. As a result of the performance evaluation, the proposed model achieved an average improvement of data processing time of 24.5% compared to the existing model and the efficiency of the proposed model was improved by 13.7% than the existing model because the user's privacy information was group managed.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.12
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• pp.519-524
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• 2023

In hashing-based image retrieval, the hash code of a manipulated image is different from the original image, making it difficult to search for the same image. This paper proposes and evaluates a self-supervised deephashing model that generates perceptual hash codes from feature information such as texture, shape, and color of images. The comparison models are autoencoder-based variational inference models, but the encoder is designed with a fully connected layer, convolutional neural network, and transformer modules. The proposed model is a variational inference model that includes a SimAM module of extracting geometric patterns and positional relationships within images. The SimAM module can learn latent vectors highlighting objects or local regions through an energy function using the activation values of neurons and surrounding neurons. The proposed method is a representation learning model that can generate low-dimensional latent vectors from high-dimensional input images, and the latent vectors are binarized into distinguishable hash code. From the experimental results on public datasets such as CIFAR-10, ImageNet, and NUS-WIDE, the proposed model is superior to the comparative model and analyzed to have equivalent performance to the supervised learning-based deephashing model. The proposed model can be used in application systems that require low-dimensional representation of images, such as image search or copyright image determination.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.7C
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• pp.1015-1023
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• 2004

In order to protect an exchanged data, it is indispensable to establish a peer-to-peer key between the two communicating nodes. Pre-distributing keys among the nodes is unrealistic in Ad-Hoc network environment because of the dynamic nature of its network topology and the equal authority of its nodes. This paper presents a peer-to-peer key establishment scheme without pre-distributing keys in Ad-Hoc networks. The proposed scheme is based on the Diffie-Hellman key exchange protocol. Main idea is to prevent the falsification of Diffe-Hellman values using some elements of a hash chain. As a result, it is as safe as the underlying hash function against a man-in-the-middle attack. Simulation results have shown that the proposed scheme dramatically reduces the number of messages, and has relatively higher scalability, as compared with the key pre-distribution based scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.1B
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• pp.11-16
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• 2007

This paper describes the design and performance of a secure routing protocol with time-space cryptography for mobile ad-hoc networks. The proposed time-space scheme works in the time domain for key distribution between source and destination as well as in the space domain for intrusion detection along the route between them. For data authentication, it relies on the symmetric key cryptography due to high efficiency and a secret key is distributed using a time difference from the source to the destination. Also, a one-way hash chain is formed on a hop-by-hop basis to prevent a compromised node or an intruder from manipulating the routing information. In order to evaluate the performance of our routing protocol, we compare it with the existing AODV protocol by simulation under the same conditions. The proposed protocol has been validated using the ns-2 network simulator with wireless and mobility extensions.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.713-716
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• 2007

This paper suggests One-time Password key exchange authentication technique for a strong authentication based on Ad-hoc Networks and through identify wireless environment security vulnerabilities, analyzes current authentication techniques. The suggested authentication technique consists of 3 steps: Routing, Registration, and Running. The Routing step sets a safe route using AODV protocol. The Registration and Running step apply the One-time password S/key and the DH-EKE based on the password, for source node authentication. In setting the Session key for safe packet transmission and data encryption, the suggested authentication technique encrypts message as H(pwd) verifiers, performs key exchange and utilizes One time password for the password possession verification and the efficiency enhancement. EKE sets end to end session key using the DH-EKE in which it expounds the identifier to hash function with the modula exponent. A safe session key exchange is possible through encryption of the H(pwd) verifier.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.4
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• pp.73-79
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• 2020

Due to the rapidly ageing population and low birth rates, most countries have faced with the problems of an ageing population. As a result, research into aging and the means to support an aging population has therefore become a priority for many governments around the world. Ambient Assisted Living(AAL) approach is the way to guarantee better life conditions for the aged and for monitoring their health conditions by the development of innovative technologies and services. AAL technologies can provide more safety for the elderly, offering emergency response mechanisms and fall detection solutions. Since the information transmitted in AAL systems is very personal, however, the security and privacy of such data are becoming important issues that must be dealt with. In this paper, we propose a Chameleon hash-based secure authentication protocol for AAL systems. The proposed authentication protocol not only supports several important security requirements needed by the AAL systems, but can also withstand various types of attacks. In addition, the security analysis results show that the proposed authentication protocol is more efficient and secure than the existing authentication protocols.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.5
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• pp.71-78
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• 2009

In RFID system, the communicated data can be easily eavesdropped and tampered with by an attacker because the communication between the reader and the tag is performed in an insecure channel. Therefore, authentication is an important role in RFID applications for providing security and privacy. In 2006, Lee, Asano and Kim proposed an RFID mutual authentication protocol (the LAK protocol) which utilizes a hash function and synchronized secret information. However, Cao and Shen showed that the LAK protocol is vulnerable to replay attack, and therefore an adversary can impersonate the tag. This paper proposes a new simple two-round RFID mutual authentication (TRMA) protocol based on secure one-way hash function. As a result, the proposed TRMA protocol not only can prevent various attacks and but also provides communication efficiency since they mutually authenticate by performing two-round between RFID tag and RFID reader.