• Journal of Korea Society of Digital Industry and Information Management
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• v.19 no.1
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• pp.31-42
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• 2023

As computer performance is leveled upward, the use of IoT systems is gradually expanding. Although IoT systems are used in many fields, it is true that it is difficult to build a safe system due to performance limitations. To overcome these limitations, many researchers have proposed numerous protocols to improve security issues. Among them, Azrour et al. except. We proposed a new efficient and secure authentication protocol for remote healthcare systems in a cloud-based IoT environment, and claimed that the new protocol could solve the security vulnerabilities of the existing protocols and was more efficient. However, in this paper, through the security analysis of the remote healthcare system in the cloud-based IoT environment proposed by Azrour et al., the protocol of this system was found to be vulnerable to Masquerade attack, Lack of Perfect Forward Secrecy, Off-line password guessing attack, and Replay attack.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.11a
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• pp.473-474
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• 2022

텍스트를 기반으로 하는 패스워드는 다방면에서 가장 많이 사용되고 있는 인증 수단이다. 하지만 이러한 패스워드는 사용자의 기억에 의존하기 때문에 사람들은 일반적으로 기억하기 쉽게 '!iloveY0u'와 같은 암호를 사용한다. 이로 인해 사용자들의 패스워드 간에 규칙성이 생기게 되어 HashCat과 같은 크래킹 도구에 의해 해킹될 수 있다. 딥러닝을 통한 패스워드 예측의 경우, 일반적인 패스워드 크래킹 도구와 달리 패스워드 구조 및 속성에 대한 사전 지식 및 전문적 지식 없이도 패턴을 추출하고 학습할 수 있어 활발히 연구되고 있다. 본 논문에서는 딥러닝 모델 중에서도 순환 신경망을 사용하여 텍스트 기반의 패스워드를 예측하는 연구의 동향에 대해 알아본다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.1
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• pp.231-237
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• 2012

In 2011, Das proposed an effective biometrics-based remote user authentication scheme using smart cards that can provide strong authentication and mutual authentication, while eliminating the security drawbacks of Li-Hwang's scheme. In this paper, we have shown that Das's scheme is still insecure against several attacks and does not provide mutual authentication. Also, we proposed the enhanced scheme to overcome these security weaknesses, even if the secret information stored in the smart card is revealed. As a result of security analysis, the enhanced scheme is secure against user impersonation attack, server masquerading attack, off-line password guessing attack, and insider attack. And we can see that the enhanced scheme provides mutual authentication between the user and the server.

• Journal of the Korea Society of Computer and Information
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• v.26 no.10
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• pp.101-108
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• 2021

In this paper, we analyze Shin's proposed dynamic ID-based user authentication scheme for TMIS(Telecare Medicine Information System), and Shin's authentication scheme is vulnerable to smart card loss attacks, allowing attackers to acquire user IDs, which enables user impersonation attack. In 2019, Shin's proposed authentication scheme attempted to generate a strong random number using ECC, claiming that it is safe to lose a smart card because it is impossible to calculate random number r'i due to the difficulty of the ECC algorithm without knowing random number ri. However, after analyzing Shin's authentication scheme in this paper, the use of transmission messages and smart cards makes it easy to calculate random numbers r'i, which also enables attackers to generate session keys. In addition, Shin's authentication scheme were analyzed to have significantly greater overhead than other authentication scheme, including vulnerabilities to safety analysis, the lack of a way to pass the server's ID to users, and the lack of biometric characteristics with slightly different templates.

• Journal of the Korea Society of Computer and Information
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• v.28 no.5
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• pp.67-74
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• 2023

In this paper, we analyze the authentication protocol for DRM proposed by Hussain et al. in 2022, and present an improved solution. Hussain et al. argued that their authentication protocol guarantees man-in-the-middle attack, replay attacks, and mutual authentication. However, as a result of analyzing Hussain et al.'s authentication protocol in this paper, Hussain et al.'s authentication protocol still has an insider attack problem, a problem with Yu et al.'s authentication protocol that they pointed out. For this reason, when an inside attacker acquires information on a mobile device, a user impersonation attack was also possible. In addition, there were problems with the user's lack of ID format verification and the problem of the secret key mismatch of the digital contents between the server and the user. Therefore, this paper proposes an improved solution to solve these problems. As a result of analysis in this paper, the improved solution is safe from various attacks such as smart card attack, insider attack, and password guessing attack and can safely authenticate users of DRM.

• Journal of the Korea Society of Computer and Information
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• v.28 no.10
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• pp.93-101
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• 2023

In this paper, as a result of analyzing the TMIS authentication protocol using ECC and biometric information proposed by Chen-Chen in 2023, there were security problems such as user impersonation attack, man-in-the-middle attack, and user anonymity. Therefore, this paper proposes an improved authentication protocol that provides user anonymity to solve these problems. As a result of analyzing the security of the protocol proposed in this paper, it was analyzed to be secure for various attacks such as offline password guessing attack, user impersonation attack, smart-card loss attack, insider attack, perfect forward attack. It has also been shown to provided user privacy by guaranteeing user anonymity and untraceability, which must be guaranteed in TMIS. In addition, there was no significant increase in computational complexity, so the efficiency of execution time was achieved. Therefore, the proposed protocol in this paper is a suitable user authentication protocol for TMIS.

• KIPS Transactions on Computer and Communication Systems
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• v.13 no.1
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• pp.31-37
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• 2024

Conventional secret sharing techniques often derive shares from randomly generated polynomials or planes, resulting in lengthy and complex shares that are challenging to memorize and/or manage without the aid of a separate computer or specialized device. Modifying existing secret sharing methods to use a predetermined value, such as a memorizable password or bio-metric information, offers a solution. However, this approach raises concerns about security, especially when the predetermined value lacks randomness or has low entropy. In such cases, adversaries may deduce a secret S with just (t - 1) shares by guessing the predetermined value or employing brute force attacks. In this paper, we introduce a share hardening method designed to ensure the security of secret sharing while enabling the use of memorizable passwords or biometric information as predetermined shares.

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