• Review of KIISC
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• v.18 no.3
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• pp.41-47
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• 2008

본 논문은 기존의 패스워드 인증 시스템의 취약점 문제 및 이에 대응하여 제안된 다수의 영상 기반 인증 시스템을 소개하고, 인증 과정에서 2차원 또는 3차원 영상 내의 이동하면서도 기억하기 쉬운 다수의 화소 정보에 기반을 둔 향상된 영상기반 전략을 소개한다. 최근 관심의 대상이 되고 있는 바와 같이, 인증 과정에서 입력되는 패스워드에 대한 감시 문제의 심각성에도 불구하고 그동안 취약한 사용자 신분증명에 대한 납득할 만한 대안이 부재하였다. 따라서 신중하게 설계된 보안 기반구조에도 불구하고 사용자 패스워드는 많은 응용에서 키보드 감시나 어깨너머로 훔쳐보기를 통하여 타인에게 쉽게 노출될 수 있다. 제안한 방안은 패스워드 인증에 문자열을 사용하지 않으므로 악의적 감시가 쉽지 않고, 소유자에게는 보다 기억하기 쉬우면서도 타인에게는 정보 노출을 최소화 할 수 있으므로 최근의 패스워드 유출 문제에 대한 훌륭한 대응책일 뿐만 아니라 키보드를 갖지 않는 휴대 장치를 위한 인증 방안으로도 활용 가능하다.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.53-55
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• 2015

최근 사용자 인증을 요구하는 시스템들은 사용자의 개인정보를 안전하게 지키기 위해 패스워드를 주기적으로 변경하거나 영문자, 숫자 그리고 특수문자를 혼합한 복잡한 구조를 사용한다. 그러나 패스워드를 관리하는 사용자들은 기억에 의존하고 있으며, 쉽게 기억하기 위해 단순한 패스워드 사용을 선호한다. 따라서 본 연구에서는 사용자의 개인정보를 안전하게 지키기 위해 사용자 인증에 필요한 패스워드를 주기적으로 변경하고, 복잡한 구조를 갖도록 패턴 기반의 동적 패스워드 생성 기법을 제안한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.1213-1216
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• 2010

인터넷을 통한 IT환경의 변화로 개인정보를 이용한 다양한 서비스들이 등장하게 되었고, 이에 따라 개인정보보안의 중요성이 증대되고 있다. 정당한 사용자를 확인하는 인증기술의 발달로 한 세션에서 패스워드 값을 사용 후 폐기하는 일회용 패스워드에 관한 연구가 활발히 진행되고 있다. 그러나 기존의 일회용 패스워드는 기밀성, 상호인증, 연산량 등 여러 문제점을 내포하고 있다. 따라서 본 논문에서는 이러한 기존의 일회용 패스워드의 문제점을 분석하고 이를 해결하기 위해 타원곡선 암호 알고리즘을 이용한 일회용 패스워드 생성 기법에 관하여 제안하였다. 제안방식은 암호 알고리즘을 이용하여 기밀성을 제공하며, 서버와 클라이언트 간의 상호인증을 제공할 수 있도록 하였다.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.9
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• pp.215-224
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• 2012

Using password on system is easy to build and shorten the access time to authorize user, which is high in use for vary system that requires users' authorization. Many input device are able to perform the password system easily, such as PC, smart-phone, tablet PC, etc. Beside the high usability of password, physical attack occurs when user put their password on the device, known as Shoulder Surfing attack. It used to be formed in numbers, characters or mix of different kinds, but new kind of password arose. Exploiting image or making scenarios are those kinds which are able to reflect users' intentions. Not many estimation exists for new password, so there's need to be standard for those new password for highlighting usability and accessability. In this paper, we propose password system with simple image and switching key-board to test statistical method to estimate usability on the password.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.5
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• pp.291-298
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• 2002

Mutual authentication is essential for key exchange protocols and password-based authentication scheme is used widely, which is convenient to users and executed on the cheap. Password-based protocol should be not only secure against attach but also efficient to reduce user's load. In this paper, we propose a new key exchange protocol, called OTP-EKE(One Time Password based Encrypted Key Exchange), to provide authentication and to share a session key between a server and a user. We choose a password-based scheme as a user authentication. Especially, we use a one-time-password verifier and server's public password to protect against attacks on server's directory. As for efficiency, we improve the performance by reducing the number of modular exponentiations and the number of rounds.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.12
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• pp.2289-2296
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• 2016

The password rules to be applied for the user account creation are often different by websites. Thus we often forget the password to sign in website and it creates waste of time for frequent password reset. In order to solve this problem we propose a new authentication method in this paper. When user forget the password to sign in, the existing methods require a password reset step but our proposed method provides new sign in scheme through the additional authentication step with base password and personal information registered at the member sign up stage. From the result of performance comparison the proposed method is considered to be more efficient than others because it provides not only an equivalent level of security with others but also requires only a half of the number of transactions and the time required for password reset step.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.4B
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• pp.435-441
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• 2009

The one-time password system solves the problem concerning password reuse caused by the repeated utilization of an identical password. The password reuse problem occurs due to the cyclic repetition at the time of password creation, and authentication failure can occur due to time deviation or non-synchronization of the number of authentication. In this study, the password is created asynchronously and exchanged with the user, who then signs using a digital signature in exchange for the password and a valid verification is requested along with the certificate to ensure non-repudiation. Besides this, a verification system for one-time password is proposed and designed to improve security by utilizing the validity verification that is divided into certificate verification and password verification. Comparative analysis shows that the mechanism proposed in this study is better than the existing methods in terms of replay attack, non-repudiation and synchronization failure.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.6
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• pp.1251-1259
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• 2017

One-time password has been proposed for the purpose of addressing the security problems of the simple password system: fixed passwords and pre-shared passwords. Since it employs the consecutive hash values after a root hash value is registered at the server, the security weakness of the fixed passwords has been addressed. However, it has a shortcoming of re-registering a new root hash value when the previous hash chain's hash values are exhausted. Even though several one-time password systems not requiring re-registration have been proposed, they all have several problems in terms of constraint conditions and efficiency. In this paper, we propose the one - time password scheme based on a hash chain that generates one - time passwords using only two cryptographic hash functions at each authentication and satisfies the existing constraints without re-registration, Security requirements and efficiency.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.1
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• pp.17-27
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• 2020

Many users are using password managers in order to conveniently manage several usernames and passwords needed to access the web sites. The password manager encrypts and stores several passwords on the server, and the user accesses the server to receive the password information. Thus, if an attacker can sniff a message between the password manager and the server and decrypt the message content, or if an attacker can steal the computer's memory and decrypt the message content, then all the passwords will be exposed to the attacker. In this paper, we analyze the client-server communications and encryption process of password mangers and show there is a serious vulnerability in memory attack.

• The KIPS Transactions:PartC
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• v.15C no.2
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• pp.125-132
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• 2008

As the development of Internet technology, the number of IDs managed by each individuals has been increased. And many software development institutes have developed ID/PW management solutions to facilitate secure and convenient management of ID/PW. However, these solutions also can be vulnerable in case of administrator's password exposure. Thus, we need to derive security requirements from the vulnerability analysis of these solutions, also we need evaluation criteria for secure ID/PW management solution development. In this paper, we analyze the vulnerability of ID/PW management solution and propose the evaluation criteria for secure ID/PW management solution.