• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.4
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• pp.807-816
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• 2015

During the last decade most of coordinated security breaches are performed by the means of botnets, which is a large overlay network of compromised computers being controlled by remote botmaster. Due to high volumes of traffic to be analyzed, the challenge is posed by managing tradeoff between system scalability and accuracy. We propose a novel Hadoop-based P2P botnet detection method solving the problem of scalability and having high accuracy. Moreover, our approach is characterized not to require labeled data and applicable to encrypted traffic as well.

• The KIPS Transactions:PartD
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• v.9D no.5
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• pp.931-938
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• 2002

We implement the PBSM (Protocol-Based Security Module) system which guarantees the secure data transmission under web circumstances. There are two modules to implement for the PBSM architecture. One is Web Server Security Module (WSSM) which is working on a web server, the other is the Winsock Client Security Module (WSCSM) which is working on a client. The WSCSM security module decrypts the encrypted HTML document that is received from the security web server The decrypted HTML document is displayed on the screen of a client. The WSSM module contains the encryption part for HTML file and the decryption part for CGI (Common Gateway Interface). We also implement the proposed idea at the web system.

• Journal of KIISE:Information Networking
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• v.34 no.3
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• pp.175-185
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• 2007

In IEEE 802.15.4 (Low-Rate Wireless Personal Area Network) specification, a successful reception and validation of a data or MAC command frame can be confirmed with an acknowledgment. However, the specification does not support security for acknowledgment frame; the lack of a MAC covering acknowledgments allows an adversary to forge an acknowledgment for any frame. This paper proposes an identity authentication mechanism at the link layer for acknowledgment frame in IEEE 802.15.4 network. With the proposed mechanism there is only three bits for authentication, which can greatly reduce overhead of device. The encrypted bit stream for identity authentication will be transmitted to device by coordinator within association process. Statistical method and simulation results prove that our mechanism is successful in handling MAC layer attack.

• Journal of Korea Multimedia Society
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• v.11 no.5
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• pp.588-596
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• 2008

For the patients' privacy, secure access control of medical images is essentially necessary. In this paper, two types of Region of Interest (ROI)-based selective encryption schemes are proposed, which concentrate on the security of crucial parts in medical images. The first scheme randomly inverts the most significant bits of ROI coefficients in several high frequency subbands in the transform domain, which only incurs little loss on compression efficiency. The second scheme employs a symmetric key encryption to encrypt selectively the ROI data in the final code-stream, which provides sufficient confidentiality. Both of two schemes are backward compatible so as to ensure a standard bitstream compliant decoder so the encrypted images can be reconstructed without any crash.

• The Journal of the Korea Contents Association
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• v.1 no.1
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• pp.74-82
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• 2001

Visual cryptography made it possible to decrypt the Information encrypted by thresholding scheme not with digital system but with human vision system. This method, however, has some limit in it because of the rack of resolution in both the spatial and amplitude domain. Optical visual cryptography, which used laser system instead of human eyesight, was proposed by conjunction of the optical theory with the cryptography. However, it also had some difficulties because it did not overcome the existing problem of visual cryptography completely. The problem occurred in the process of transferring data processing system from visual to optics. Therefore, it is appropriate to approach these problems in terms of optics. In this paper, we analysis, in the aspect of frequency, the security characteristics and the noise level occurred in the process of optical visual encryption.

• Journal of Korea Multimedia Society
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• v.7 no.12
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• pp.1719-1728
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• 2004

The fusion of Internet technology and applications with wireless communication provides a new business model and promises to extend the possibilities of commerce to what is popularly called mobile commerce, or m-commerce. In mobile Internet banking service through wireless local area network, security is a most important factor to consider. We describe the development of security service for mobile Internet banking on Personal Digital Assistants (PDAs). Banking Server and Authentication Server were developed to simulate banking business and to support certificate management of authorized clients, respectively. To increase security, we took hybrid approach in implementation: symmetric block encryption and public-key encryption. Hash function and random number generation were exploited to generate a secret key. The data regarding banking service were encrypted with symmetric block encryption, RC4, and the random number sequence was done with public-key encryption. PDAs communicate through IEEE 802.IIb wireless LAN (Local Area Network) to access banking service. Several banking services and graphic user interfaces, which emulatedthe services of real bank, were developed to verity the working of each security service in PDA, the Banking Server, and the Authentication Server.

• Journal of Korea Multimedia Society
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• v.16 no.10
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• pp.1156-1162
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• 2013

Face verification has been widely studied during the past two decades. One of the challenges is the rising concern about the security and privacy of the template database. In this paper, we propose a secure face verification system which generates a unique secure cryptographic key from a face template. The face images are processed to produce face templates or codes to be utilized for the encryption and decryption tasks. The result identity data is encrypted using Advanced Encryption Standard (AES). Distance metric naming hamming distance and Euclidean distance are used for template matching identification process, where template matching is a process used in pattern recognition. The proposed system is tested on the ORL, YALEs, and PKNU face databases, which contain 360, 135, and 54 training images respectively. We employ Principle Component Analysis (PCA) to determine the most discriminating features among face images. The experimental results showed that the proposed distance measure was one the promising best measures with respect to different characteristics of the biometric systems. Using the proposed method we needed to extract fewer images in order to achieve 100% cumulative recognition than using any other tested distance measure.

• Journal of information and communication convergence engineering
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• v.12 no.1
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• pp.19-25
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• 2014

The wireless sensor networking standard DASH7 operates in low-power communication with a better transmission quality in active RFID networks. The DASH7 security standard supports public key cryptography. At present, the DASH7 standard uses the message authentication code in the network layer for authentication and integrity. However, its security standard is still in an incubation stage with respect to the implementation of a crypto exchange over a DASH7 network. Effective key management is an important factor for privacy and security. If organizations are not careful about where and how keys are stored, they leave the encrypted data vulnerable to theft. In this regard, we present a key management system designed for efficient key management through public key infrastructure authentication as well as a non-repudiation feature for the DASH7 standard. We analyze the performance of the proposed system on a basis of various performance criteria such as latency and throughput.

• Convergence Security Journal
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• v.19 no.4
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• pp.77-85
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• 2019

As the Internet continues to evolve, cyber attacks are becoming more precise and covert. Anonymous communication, which is used to protect personal privacy, is also being used for cyber attacks. Not only it hides the attacker's IP address but also encrypts traffic, which allows users to bypass the information protection system that most organizations and institutions are using to defend cyber attacks. For this reason, anonymous communication can be used as a means of attacking malicious code or for downloading additional malware. Therefore, this study aims to suggest a method to detect and block encrypted anonymous communication as quickly as possible through artificial intelligence. Furthermore, it will be applied to the defense to detect malicious communication and contribute to preventing the leakage of important data and cyber attacks.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.3
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• pp.358-363
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• 2014

In this paper, we present two constructions of the attribute-based broadcast encryption(ABBE) algorithm. Attribute-based encryption(ABE) algorithm enables an access control mechanism over encrypted data by specifying access policies among private keys and ciphertexts. ABBE algorithm can be used to construct ABE algorithm with revocation mechanism. Revocation has a useful property that revocation can be done without affecting any non-revoked uers. The main difference between our algorithm and the classical ones derived from the complete subtree paradigm which is apt for military hierarchy. Our algorithm improve the efficiency from the previously best ABBE algorithm, in particular, our algorithm allows one to select or revoke users by sending ciphertext of constant size with respect to the number of attributes and by storing logarithm secret key size of the number of users. Therefore, our algorithm can be an option to applications where computation cost is a top priority and can be applied to military technologies in the near future.