• Proceedings of the Korea Information Assurance Society Conference
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• 2004.05a
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• pp.71-76
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• 2004

A certificate is important media for the purpose of offering user-authentication service on PKI system. In the paper we analyzed management implement which could make the efficient use of a certificate. This implement called ClientCA will make efficient use of the service about user-authentication consisting of the basis in the age of information through efficient management and partial use of each certificates. Especially, ClientCA could be used efficiently by grafting a small group of PKI system which is operated with particular purposes.

• Journal of Internet Computing and Services
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• v.9 no.2
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• pp.83-88
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• 2008

Session initiation protocol (SIP) is an application-layer prolocol to initiate and control multimedia client session. When client ask to use a SIP service, they need to be authenticated in order to get service from the server. Authentication in a SIP application is the process in which a client agent present credentials to another SIP element to establish a session or be granted access to the network service. In 2005, Yang et al. proposed a key exchange and authentication scheme for use in SIP applications, which is based on the Diffie-Hellman protocol. But, Yang et al.'s scheme is not suitable for the hardware-limited client and severs, since it requires the protocol participant to perform significant amount of computations (i.e., four modular exponentiations). Based on this observation. Huang and Wei have recently proposed a new efficient key exchange and authentication scheme thor improves on Yang et al.'s scheme. As for security, Huang and Wei claimed, among others, that their scheme is resistant to offline dictionary attacks. However, the claim turned out to be untrue. In this paper, we show thor Huang and Wei's key exchange and authentication scheme is vulnerable to on offline dictionary attack and forward secrecy.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.433-438
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• 2000

Now, It is vulnerabilities and problems of adaption in user identification and authentication on the Web environments; the BAA(Basic Access Authentication) of HTTP1.0 is that use. ID and password is passed with clear-text between client and server, For this enhancement, the DAA(Digest Access Authentication) of HTTP1.1 is that use. password is digested by MAC(Message Authentication Code) mechanism. but, this mechanism is not adapted by venders of Web browsers. This paper propose the lava based user identification and authentication model to resolve the above problems. Proposed systems are applied to the Web environment, since it has independence to web server and client.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.637-640
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• 2003

Authentication between Server and Client is necessary in most of Internet Service because of increasing of using of Internet. Unix-based Server upgraded security of user authentication using "Shadow Password" instead of "crypt" function. But "Shadow Password" most use same authentication method about all services. But we individually can set user authentication method using PAM(Pluggable Authentication Module). This paper will propose user authentication system using Linux-PAM that use SMART CARD as authentication token.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.2
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• pp.417-429
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• 2019

WPA2-PSK uses a 4-way handshake protocol based on a shared secret to establish a secure session between a client and an AP. It has various security problems such as eavesdropping attacks and the secure session establishment process is inefficient because it requires multiple interactions between client and AP. The WPA3 standard has recently been proposed to solve the security problem of WPA2, but it is a small improvement using the same 4-way handshake methodology. OAuth 2.0 token authentication is widely used on the web, which can be used to keep an authenticated state of a client for a long time by using tokens issued to an authenticated client. In this paper, we apply the dual-token based randomized token authentication technology to the Wi-Fi security protocol to achieve an efficient Wi-Fi security protocol by dividing initial authentication and secure session establishment. Once a client is authenticated and equipped with dual tokens issued by AP, it can establish secure session using them quickly with one message exchange over a non-secure channel.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.2
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• pp.3-13
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• 2004

DRM is the ability to brand digital contents with features that ensure copy Protection and affect the way in which digital contents are played back. DRM is a technology that enables the secure distribution, promotion and sale of digital contents on the Internet. The DRM Client System that operates on the untrusted user environments has to meet the requirements of the contents owner, including copyright and contents protection. After the DRM Client System is installed on the untrusted user environments, it verifies and plays digital contents. With these procedures it cuties out user authentication, contents decryption, and license management. During these procedures, the sensitive data, including authentication information, decryption data and license data, must be secured against any illegal access from users. The goal of this thesis is to introduce the implementation of Secure Storage Device which can protect user's authentication key, cryptographic key, and license data in safe where the DRM Client System is running.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.200-202
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• 2017

To improve the security of OAuth 2.0 access token transportation and satisfy the challenge of resources constraint caused by the bearer token access mechanism of the OAuth 2.0, we proposed an extensional client authentication scheme that is based on the Proof-of-Possession (PoP) token mechanism. By improving the integrity of PoP token, we bind a PoP key of a public/private key pair to the PoP token. The authorization server and the resource server can authenticate the identity of the client by verifying whether the client has the possession of the PoP token. If the client can prove that it has a PoP key that matches the PoP token, then the identity of the client can be authenticated. This experimental evaluation can confirm that this scheme effectively dealing with the issue of client identity authentication and reduce resources consumption.

• Journal of the Korea Society of Computer and Information
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• v.17 no.12
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• pp.159-167
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• 2012

The authentication system of the PKI(public key infrastructure) provides the authenticity and security, accessibility, economic feasibility, and convenience to the service provider and users. Therefore the public and private companies in Korea widely use it as the authentication method of the web service. However, the safety client system is threatened by many vulnerable factors which possibly caused when using PKI-based authentication system. Thus, in this article vulnerable factors caused by using the PKI-based authentication system will be analyzed, which is expected to be the useful data afterwards for the construction of the new authentication system as well as performance improvement.

• Journal of the Korea Convergence Society
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• v.2 no.4
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• pp.9-14
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• 2011

Phishing is an attack to theft an user's identity by masquerading the user or the device. The number of phishing victims are sharply increased due to wide spread use of smart phones and messenger programs. Smart phones can operate various wi-fi based apps besides typical voice call and SMS functions. Generally, the messenger program such as Kakao Talk or Nate On is consisted of client and server functions. Thus, the authentication between the client and the server is essential to communicate securely. In this paper, we propose the messenger authentication protocol safe against smart phone phishing. To protect communications among clients, the proposed method provides message encryption and authentication functions.

• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.4
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• pp.139-150
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• 2009

Authentication and key exchange are fundamental for establishing secure communication channels over public insecure networks. Password-based protocols for authenticated key exchange are designed to work even when user authentication is done via the use of passwords drawn from a small known set of values. There have been many protocols proposed over the years for password authenticated key exchange in the three-party scenario, in which two clients attempt to establish a secret key interacting with one same authentication server. However, little has been done for password authenticated key exchange in the more general and realistic four-party setting, where two clients trying to establish a secret key are registered with different authentication servers. In fact, the recent protocol by Yeh and Sun seems to be the only password authenticated key exchange protocol in the four-party setting. But, the Yeh-Sun protocol adopts the so called "hybrid model", in which each client needs not only to remember a password shared with the server but also to store and manage the server's public key. In some sense, this hybrid approach obviates the reason for considering password authenticated protocols in the first place; it is difficult for humans to securely manage long cryptographic keys. In this work, we introduce a key agreement protocol and a key distribution protocol, respectively, that requires each client only to remember a password shared with its authentication server.