• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.3C
• /
• pp.220-225
• /
• 2002

Mobile IP aims to support mobility within the Internet. This paper concerned with the security aspect of Mobile IP. We show that current registration protocol has a possible replay attack despite the use of authenticated registration message and replay protection. We propose a public-key based registration protocol that also distributes a session-key distribution protocol in AAA. Proposed protocol provides authentication of mobile node and session-key distribution simultaneously. It also provides non-repudiation of service request.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2011.11a
• /
• pp.735-738
• /
• 2011

회원가입 정보를 이용하는 대다수의 웹 어플리케이션은 쿠키 및 세션을 이용한 인증기법으로 로그인 인증을 한다. 그러나, 쿠키에 의존하여 로그인 인증을 하는 웹 어플리케이션은 재전송 공격(Replay Attack)에 취약하다. 재전송 공격이란 사용자가 로그인할 때 쿠키의 정보를 해커가 스니핑(Sniffing)하여 Opera 웹브라우저의 쿠키 관리자에서 강제로 재전송하여 위장할 수 있는 공격을 말한다. 본 논문에서는 쿠키와 세션 인증키를 이용하여 재전송 공격을 방어할 수 있는 알고리즘을 제안하였다. 그리고, 클라이언트와 서버간에 신뢰할 수 없는 통신으로 인한 스니핑의 문제점을 서버에만 저장된 암호화된 세션 인증키로 개선하였다.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
• /
• 2006.06a
• /
• pp.171-175
• /
• 2006

Diffie-Hellman기반 키 합의 프로토콜들은 비교적 고비용의 연산인 지수연산으로 인해, 유선 네트워크 환경에 비해 저전력이고 컴퓨팅 자원이 제한되어 있는 무선 네트워크 환경에서는 비효율적이고 구현하기 어려운 문제가 있다. 이에 Yang등은 대리서버(Proxy Server)를 이용하여 Diffie-Hellman방식을 적용하면서도 단말 무선 네트워크 사용자의 지수연산부담을 감소시키는 효율적인 키 합의 프로토콜(이하 SEKAP)을 제안하였다. 그러나 SEKAP는 재전송공격(Replay Attack), 알려지지 않은 키 공유 공격(Unknown Key Share Attack), 그리고 키 노출로 인한 위장공격(Key Compromised Impersonation Attack) 등에 취약하며 전방향 안전성(Forward Secrecy)을 제공하지 못한다. 본 논문에서는 SEKAP가 위 공격들에 대해 취약함을 보이고, 세션키의 상호인증을 추가한 개선된 프로토콜을 제안한다.

• Journal of the Korea Society of Computer and Information
• /
• v.16 no.3
• /
• pp.251-260
• /
• 2011

In this paper, we proposed a scheme that it safely exchanges encrypted keys without Trust Third Party (TTP) and Pre-distributing keys in multi-hop clustering sensor networks. Existing research assume that it exists a TTP or already it was pre-distributed a encrypted key between nodes. However, existing methods are not sufficient for USN environment without infrastructure. Some existing studies using a random number Diffie-Hellman algorithm to solve the problem. but the method was vulnerable to Replay and Man-in-the-middle attack from the malicious nodes. Therefore, authentication problem between nodes is solved by adding a ��TESLA. In this paper, we propose a modified Diffie-Hellman algorithm that it is safe, lightweight, and robust pair-wise agreement algorithm by adding One Time Password (OTP) with timestamp. Lastly, authentication, confidentiality, integrity, non-impersonation, backward secrecy, and forward secrecy to verify that it is safe.

• 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.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.21 no.5
• /
• pp.83-94
• /
• 2011

Yoking proof is a concept proposed by A. Juels in 2004. It proves that a pair of tags are scanned simultaneously by one reader. After the first yoking proof protocol is proposed by A. Juels, replay attack vulnerabilities of yoking proof are considered and many other yoking proof schemes are proposed to improve it. However, compared with the first yoking proof scheme which emphasizes protocol efficiency due to the limited performance of tags, other yoking proof protocols need more computing power and storage of the tags. We propose two security protocols that consider both the general condition and limited performance of tags. The proposed scheme can protect the tags from replay attack and Brute-force attack as well. Moreover, many pairs of tags or several tag groups can be proved at the same time by executing the protocol only once.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.12
• /
• pp.5895-5901
• /
• 2011

This paper shows that a scheme provided by An[7] is not enough to satisfy security requirements for a user certification using a password-based smart card. In order to compensate this weakness, this study provides an improved user scheme with a hash function and ElGamal signature. This new scheme has some advantages protecting password guessing attack, masquerade, and replay attack as well as providing forward secrecy. Compared to An's certification scheme, this scheme suggests that the effect of computational complexity is similar but the efficiency of safety is better.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.22 no.6
• /
• pp.1219-1230
• /
• 2012

Recently, lots of users are using wireless LAN providing authentication and confidentiality with security mechanism such as WEP, WPA. But, weakness of each security mechanism was discovered and attack methods that user's information was exposed or modified to the third parties with it and abused by them were suggested. In this paper, we analyzed architecture of security mechanisms in wireless LAN and performed PSK cracking attack and cookie session hijacking attack with the known vulnerability. And, an improved 4-way handshake mechanism which can counter PSK cracking attack and a cookie replay detection mechanism which can prevent cookie session hijacking attack were proposed. Proposed mechanisms are expected to apply to establish more secure wireless LAN environment by countering existing vulnerability.

• Journal of the Korea Society of Computer and Information
• /
• v.29 no.6
• /
• pp.53-60
• /
• 2024

In this paper, we analyze the authentication scheme of Hwang et al. proposed in 2023 and propose a new authentication scheme that improves its problems. Hwang et al. claimed that their authentication scheme was practical and secure, but as a result of analysis in this paper, it is possible to attack the password/ID guessing attack and session key disclosure attack due to insider attack and stolen smart card attack. In addition, Hwang et al.'s authentication scheme, which provides user anonymity, does not provide user untraceability due to its unstable design. The proposed authentication scheme, which improves these problems, not only provides user untraceability, but also is secure for stolen smart card attack, insider attack, session key disclosure attack, and replay attack. In addition, except for one fuzzy extraction operation, it shows the same complexity or very similar one as related authentication schemes. Therefore, the proposed authentication scheme can be said to be an authentication scheme with safety and practicality.

• Journal of the Korea Society of Computer and Information
• /
• v.17 no.2
• /
• pp.159-166
• /
• 2012

Many biometrics-based user authentication schemes using smart cards have been proposed to improve the security weaknesses in user authentication system. In 2010, Chang et al. proposed an improved biometrics-based user authentication scheme without concurrency system which can withstand forgery attack, off-line password guessing attack, replay attack, etc. In this paper, we analyze the security weaknesses of Chang et al.'s scheme and we have shown that Chang et al.'s scheme is still insecure against man-in-the-middle attack, off-line biometrics guessing attack, and does not provide mutual authentication between the user and the server. And we proposed the improved scheme to overcome these security weaknesses, even if the secret information stored in the smart card is revealed. As a result, the proposed scheme is secure for the user authentication attack, the server masquerading attack, the man-in-the-middle attack, and the off-line biometrics guessing attack, does provide the mutual authentication between the user and the remote server. And, in terms of computational complexities, the proposed scheme is more effective than Chang et al.'s scheme.