• Journal of Information Processing Systems
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• v.12 no.4
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• pp.688-710
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• 2016

Our approach permits to capitalize the expert's knowledge as business rules by using an agent-based platform. The objective of our approach is to allow experts to manage the daily evolutions of business domains without having to use a technician, and to allow them to be implied, and to participate in the development of the application to accomplish the daily tasks of their work. Therefore, the manipulation of an expert's knowledge generates the need for information security and other associated technologies. The notion of cryptography has emerged as a basic concept in business rules modeling. The purpose of this paper is to present a cryptographic algorithm based approach to integrate the security aspect in business rules modeling. We propose integrating an agent-based approach in the framework. This solution utilizes a security agent with domain ontology. This agent applies an encryption/decryption algorithm to allow for the confidentiality, authenticity, and integrity of the most important rules. To increase the security of these rules, we used hybrid cryptography in order to take advantage of symmetric and asymmetric algorithms. We performed some experiments to find the best encryption algorithm, which provides improvement in terms of response time, space memory, and security.

• Journal of Information Technology Application
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• v.1 no.3_4
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• pp.91-112
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• 1999

대부분의 암호이론은 공개되어 있기 때문에 정보보안 기술의 안전성은 암호 알고리즘과 키 길이에 의존성이 크다. 본 논문에서는 해쉬함수와 카오스 함수를 이용하여 암·복호화를 위한 권장 키 길이보다 작은 길이의 일회성을 갖는 공개키와 비밀키를 생성하여 공개키 암호 알고리즘의 대표격인 RSA 암호방식에 적용하여 본다. 소인수 분해 알고리즘의 개선·발전과 시스템의 처리속도 증가에서 오는 키길이 증가 문제를 해결하므로 스마트 카드와 같은 제한된 메모리에서 실용적으로 사용할 수 있을 뿐만 아니라, 암·복호화를 수행하는 처리 시간을 단축 시킬 수 있으며, 키 관리면에서도 여러개의 공개키/비？키를 사용하는 경우보다 실용적이다.

• Journal of the Korea Society of Computer and Information
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• v.3 no.4
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• pp.91-96
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• 1998

In this paper we designed a secure client-server system to be able to protect messages between client and server using cryptography We authenticated each other using a asymmetric encryption algorithm on the logon procedure and minimized the time to encrypt and decrypt messages using a symmetric encryption algorithm on exchanging messages. We proved that it is possible to make a digital signature on our secure client-server system. And we suggested the efficient key management method to generate and distribute cryptograpic key securely.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.5
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• pp.2698-2717
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• 2019

This paper proposes a multi-stage encryption technique to enhance the level of secrecy of image to facilitate its secured transmission through the public network. A great number of researches have been done on image secrecy. The existing image encryption techniques like visual cryptography (VC), steganography, watermarking etc. while are applied individually, usually they cannot provide unbreakable secrecy. In this paper, through combining several separate techniques, a hybrid multi-stage encryption technique is proposed which provides nearly unbreakable image secrecy, while the encryption/decryption time remains almost the same of the exiting techniques. The technique consecutively exploits VC, steganography and one time pad (OTP). At first it encrypts the input image using VC, i.e., splits the pixels of the input image into multiple shares to make it unpredictable. Then after the pixel to binary conversion within each share, the exploitation of steganography detects the least significant bits (LSBs) from each chunk within each share. At last, OTP encryption technique is applied on LSBs along with randomly generated OTP secret key to generate the ultimate cipher image. Besides, prior to sending the OTP key to the receiver, first it is converted from binary to integer and then an asymmetric cryptosystem is applied to encrypt it and thereby the key is delivered securely. Finally, the outcome, the time requirement of encryption and decryption, the security and statistical analyses of the proposed technique are evaluated and compared with existing techniques.

• Journal of Korea Multimedia Society
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• v.7 no.9
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• pp.1282-1293
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• 2004

This paper proposes an asymmetric watermarking system using Public Key Infrastructure. The distinguishing characteristic of the proposed method connects between the two different techniques, cryptography technique and watermarking technique, by using the authentication technique. The connection between the two techniques are established based on the special qualities of each technique. Watermarks that are inserted into the digital contents consist of a digital signature described as an encrypted copyright information with the private key of a distributor or a copyright holder, and an authentication code. In the situation where the ownership of the digital contents has to be decided, authentication technique examines the data integrity of the digital contents based on an authentication and decides the ownership of the digital contents by examining whether it satisfies or not satisfies the integrity test. The formal case uses decryption method which compares the user defined copyright information, and the decrypted copyright information extracted from the watermark in the digital contents that are decrypted by distributors' public key The latter case determines the ownership by comparing the similarity between encrypted copyright information separated from the watermark that are extracted from the digital contents, and the user defined encrypted copyright information that are separated from the watermark The proposed method provides protection from the assault which attempts to identify or erase the encoding key.

• KIPS Transactions on Software and Data Engineering
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• v.9 no.2
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• pp.39-44
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• 2020

In this paper, we show a modified Diffie-Hellman key exchange protocol that can exchange keys by exposing only minimal information using pre-computable session key pairs. The discrete logarithm problem, which provides the safety of existing Diffie-Hellman and Diffie-Hellman based techniques, is modified to prevent exposure of primitive root. We prove the algorithm's operation by applying the actual value to the proposed scheme and compare the execution time and safety with the existing algorithm, shown that the security of the algorithm is improved more than the product of the time complexity of the two base algorithms while maintaining the computation amount at the time of key exchange. Based on the proposed algorithm, it is expected to provide a key exchange environment with improved security.

• Journal of Internet of Things and Convergence
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• v.8 no.1
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• pp.79-85
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• 2022

Internet of Things (IoT) connects devices with various platforms, computing power, and functions. Due to the diversity of networks and the ubiquity of IoT devices, demands for security and privacy are increasing. Therefore, cryptographic mechanisms must be strong enough to meet these increased requirements, while at the same time effective enough to be implemented in devices with long-range specifications. In this paper, we present the performance and memory limitations of modern cryptographic primitives and schemes for different types of devices that can be used in IoT. In addition, detailed performance evaluation of the performance of the most commonly used encryption algorithms in low-spec devices frequently used in IoT networks is performed. To provide data protection, the binary ring uses encryption asymmetric fully homomorphic encryption and symmetric encryption AES 128-bit. As a result of the experiment, it can be seen that the IoT device had sufficient performance to implement a symmetric encryption, but the performance deteriorated in the asymmetric encryption implementation.

• The KIPS Transactions:PartC
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• v.15C no.6
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• pp.439-446
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• 2008

Recently, the importance of EPCglobal Network and brisk researches on the RFID technologies and application have been increasing, also a number of industries including distribution and logistics are proposing various systems of the application. The Standard for EPCglobal Network, as now being in the process of its legislation, stipulates X.509 only for the method of encryption, without accurate specifications. This paper is, thus, to suggest the way of sending safely messages for the web-based service constituting EPCglobal Network, of verifying whether the received messages are effective, of encoding the messages for safer sending and of certifying between systems, and then to implement the way.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.1
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• pp.511-535
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• 2017

Internet banking is one of many services provided by financial institutions that have become very popular with an increasing trend. Due to the increased amount of usage of the service, Internet banking has become a target from adversaries. One of the points that are at risk of an attack is the login process. Therefore, it is necessary to have a security mechanism that can reduce this risk. This research designs and develops a multi-factor authentication protocol, starting from a registration system, which generates authentication factors, to an actual authentication mechanism. These factors can be categorised into two groups: short term and long term. For the authentication protocol, only three messages need to be exchanged between a client and a financial institution's server. Many cryptographic processes are incorporated into the protocol, such as symmetric and asymmetric cryptography, a symmetric key generation process, a method for generating and verifying digital signatures. All of the authentication messages have been proved and analysed by the logic of GNY and the criteria of OWASP-AT-009. Even though there are additional factors of authentication, users do not really feel any extra load on their part, as shown by the satisfactory survey.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.2 no.5
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• pp.265-277
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• 2008

In spite of previous common assumptions about the incompatibility of public key cryptography (PKC) schemes with wireless sensor networks (WSNs), recent works have shown that they can be utilized for such networks in some manner. The major challenge of employing a PKC-based scheme in a wireless sensor network is posed by the resource limitations of the tiny sensors. Considering this sensor feature, in this paper we propose an efficient PKC-based security architecture with relatively lower resource requirements than those of previously proposed PKC schemes for WSN. In addition, our scheme aims to provide robust security in the network. Our security architecture comprises two basic components; a key handshaking scheme based on simple, linear operations and the derivation of a decryption key by a receiver node. Our architecture enables node-to-base-station and node-to-node secure communications. Analysis and simulation results show that our proposed architecture ensures a good level of security for network communications, and can be effectively implemented with the limited computational, memory, and energy budgets of current-generation sensor nodes.