• Journal of KIISE:Software and Applications
• /
• v.32 no.12
• /
• pp.1238-1246
• /
• 2005

This thesis is written with web security module for safe data transmission between heterogeneous systems(ex. OS). Web system has allowed users to have great convenience and a lot of information. Though web service business has been progressed much, because of the limitation of it's own system, lots of loss, derived from data spillage which is the weakest point of security, has also followed. Suggested security module is realized by two module. One for server security module for web server, the other is client security module for client. The security structure, suggested on this thesis guarantee safe data transmission by only simple installation of modules in clients and servers. for speed sensitive transmission between web server and browser, Triple-DES, symmetric encryption system suitable for fast encryption communication, is adapted. To solve problems caused from key management, Diffie-Hellman's key exchange algorithm is adapted. By this method, all symmetric encryption troubles from key distribution and management, speed could be work out a solution. And Diffie-Hellman type algorithm secures Authentication for safe data Protection.

• Journal of the Korea Society of Computer and Information
• /
• v.13 no.5
• /
• pp.229-236
• /
• 2008

In this paper, re proposed scheme that it safely exchange encrypted keys without Trust Third Party(TTP) and Pre-distributing keys in ubiquitous environments. Existing paper assume that exist a TTP or already pre-distributed encrypted keys between nodes. However, there methods are not sufficient for wireless environments without infrastructure. Some existing paper try to use the Diffie-Hellman algorithm for the problem, but it is vulnerable to Replay and Man-in-the middle attack from the malicious nodes. Therefore, Authentication problem between nodes is solved by modified the Diffie-Hellman algorithm using ${\mu}TESLA$. We propose safe, lightweight, and robust pair-wise agreement algorithm adding. One Time Password(OTP) using timestamp to modified the Diffie-Hellman in ubiquitous environments, and verify a safety about proposed algorithm.

• Proceedings of the Korean Information Science Society Conference
• /
• 2000.04a
• /
• pp.406-408
• /
• 2000

컴퓨터와 네트워크의 보급이 일반화되면서 인터넷을 통한 정보 전달이 일상 생활처럼 되고 있다. 이러한 현상에 맞추어 등장한 인스턴트 메신저는 즉각적인 메시지의 전달이라는 장점으로 인해 국내에서도 사용자가 급속히 늘고 있다. 그러나 현재와 같이 아무런 보호장치 없이 네트워크를 통해 사용자 정보나 메시지가 노출되면 잠재적 보안 위험이 따르게 되며, 전송되는 정보의 암호화를 포함하는 안전한 인스턴트 메신저 서비스의 필요성이 대두되고 있다. 본 논문에서는 보안 기능이 포함된 안전한 인스턴트 메신저를 설계하고 자바 언어를 이용하여 구현하였으며, 시스템 설계는 일반 사용자도 쉽게 사용할 수 있고 관리가 편리한 시스템에 역점을 두었다.

• Journal of applied mathematics & informatics
• /
• v.39 no.1_2
• /
• pp.93-103
• /
• 2021

In this paper I am considering several cryptological threads. The problem of the RSA cipher, like the Diffie-Hellman protocol, is the use of finite sets. In this paper, I generalize the RSA cipher and DH protocol for infinite sets using monoids. In monoids we can not find the inverse, which makes it difficult. In the second part of the paper I show the applications in cryptology of polynomial composites and monoid domains. These are less known structures. In this work, I show different ways of encrypting messages based on infinite sets.

• Journal of KIISE:Information Networking
• /
• v.31 no.4
• /
• pp.353-362
• /
• 2004

Mobile Ad-Hoc network tends to expose scarce computing resources and various security threats because all traffics are carried in air along with no central management authority. To provide secure communication and save communication overhead, a scheme is inevitable to serurely establish session keys. However, most of key establishment methods for Ad-Hoc network focus on the distribution of a group key to all hosts and/or the efficient public key management. In this paper, a secure and efficient scheme is proposed to establish a session key between two Ad-Hoc nodes. The proposed scheme makes use of the secret sharing mechanism and the Diffie-Hellman key exchange method. For secure intra-cluster communication, each member node establishes session keys with its clusterhead, after mutual authentication using the secret shares. For inter-cluster communication, each node establishes session keys with its correspondent node using the public key and Diffie-Hellman key exchange method. The simulation results prove that the proposed scheme is more secure and efficient than that of the Clusterhead Authentication Based Method(1).

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.19 no.3
• /
• pp.73-82
• /
• 2009

This paper proposes an efficient and secure user authentication and key agreement scheme instead of the HTTP digest and TLS between the SIP UA and server. Although a number of security schemes for authentication and key exchange in SIP network are proposed, they still suffer from heavy computation overhead on the UA's side. The proposed scheme uses the HTIP Digest authentication and employs the Diffie-Hellman algorithm to protect user password against dictionary attacks. For a resource-constrained SIP UA, the proposed scheme delegates cryptographically computational operations like an exponentiation operation to the SIP server so that it is more efficient than the existing schemes in terms of energy consumption on the UA. Furthermore, it allows the proposed scheme to be easily applied to the deployed SIP networks since it does not require major modification to the signaling path associated with current SIP standard.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.9 no.2
• /
• pp.162-170
• /
• 2016

The key exchange protocols are very important to provide the secure communication in broadband satellite access network. However key exchange protocol of ETSI(European Telecommunications Standards Institute) is vulnerable to man-in-the-middle-attack by using Diffie-Hellman algorithm. And the key exchange protocol using certification is not useful in satellite environment. We propose the key exchange protocol using Timestamp which have the resistant to man-in-the-middle-attack. Proposed protocol is able to prevent the man-in-the-middle-attack by calculated time value. Also showing experiment results, we prove that proposed protocol improve memory usage, communication amount and calculation amount than other protocols.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.45 no.5
• /
• pp.30-39
• /
• 2008

This paper proposes a secure and efficient handover authentication protocol in VANET supporting fast mobility. Although the existing schemes commonly use the hash function or XOR operation to be suitable for a light-weight mobile, it does not support the security feature such as PBS. To solve this security problem, another protocol utilizing the CGA technology is proposed but it is vulnerable to the DoS attack due to a number of exponent operations. The proposed protocol using a light-weight Diffie-Hellman provides security features and performs a reduced number of exponential operation at the MN than the existing scheme.

• Journal of the Korea Society of Computer and Information
• /
• v.11 no.2 s.40
• /
• pp.239-251
• /
• 2006

Zheng's signcryption scheme is a new encryptical scheme of which can save more expense than those of the current signature encryption by using digital signature and symmetric key encryption logically. The current signcryption schemes have a problem that is to be exposed the secret key of the receiver in the case of checking repudiation of origin by the third party. To solve this problem, a solution suggested in this paper is to use multi-purpose ID-based signcryption scheme with anonymity and unlinkability. This solution is safe and more efficient than current signcryption schemes because the suggested scheme keeps the security of the random oracle model as using Weil-pairing in encryption. and follows a formal proof of semantic security of the decisional Diffie-Hellman problem.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37C no.12
• /
• pp.1256-1262
• /
• 2012

Mobile ad hoc networks (MANETs) are infrastructure-less, autonomous, and stand-alone wireless networks with dynamic topologies. Recently, cluster-based ad hoc networks which enhance the security and efficiency of ad hoc networks are being actively researched. And routing protocols for cluster-based ad hoc networks are also studied. However, there are few studies about secure routing protocols in cluster-based ad hoc networks. In this paper, we propose secure routing protocol for cluster-based ad hoc networks. We use Diffie-Hellman key agreement, HMAC, and digital signature to support integrity of routing messages, and finally can perform secure routing.