• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.4
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• pp.3-11
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• 2004

The XML has been becoming a basis of the related application and industry standards with proliferation of electronic transactions on the web, and the standardization on XML Signature, which can be applied to the digital contents including XML objects from one or more sources, is in the progress through a joint effort of W3C(World Wide Web Consortium) and IETF(Internet Engineering Task Force). Along with this trend, the development of products implementing XML Signature has been growing, and the XML Signature products are required to implement the relevant standards correctly to guarantee the interoperability among different XML Signature products. In this paper, we propose a conformance testing method for testing the XML Signature products, which includes a testing procedure and test cases. The test cases were obtained through analysis of XML Signature standards. Finally we describe the design and uses of our XML Signature conformance testing tools which implements our testing method.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.5
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• pp.11-21
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• 2004

To authorize IPSec-VPN Client in Client-to-Gateway type of the IPSec-VPN system, it can be normally used with ID/Password verification method or the implicit authorization method that regards implicitly IPSec-VPN gateway as authorized one in case that the IPSec-VPN client is authenticated. However, it is necessary for the Client-to-Gateway type of the IPSec-VPN system to have a more effective user authorization mechanism because the ID/Password verification method is not easy to transfer the ID/Password information and the implicit authorization method has the vulnerability of security. This paper proposes an effective user authorization mechanism using an attribute certificate and designs a user authorization engine. In addition, it is implemented in this study. The user authorization mechanism for the IPSec-VPN system proposed in this study is easy to implement the existing IPSec-VPN system. Moreover, it has merit to guarantee the interoperability with other IPSec-VPN systems. Furthermore, the user authorization engine designed and implemented in this paper will provide not only DAC(Discretional Access Control) and RBAC(Role-Based Access Control) using an attribute certificate, but also the function of SSO(Single-Sign-On).

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.4
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• pp.11-27
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• 2005

To date, most identity-based key agreement protocols are based on a single PKG (Private Key Generator) environment. In 2002, Chen and Kudla proposed an identity-based key agreement protocol for a multiple PKG environment, where each PKG shares identical system parameters but possesses distinct master key. However, it is more realistic to assume that each PKG uses different system parameters including the PKG's master key. In this paper, we propose a new two party key agreement protocol between users belonging to different PKGs that do not share system parameters. We also extend this protocol to two types of tripartite key agreement protocols. We show that our two party protocol requires minimal amount of pairing computation for a multiple PKG environment and our tripartite protocol is more efficient than existing protocols. We also show that the proposed key agreement protocols satisfy every security requirements of key agreement protocol.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.4
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• pp.111-122
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• 2008

Web service is defined to support interoperable machine to machine interaction over a network and defined as distributed technologies. Recently in web service environment, security has become one of the most critical issues. An attacker may expose user privacy and service information without authentication. Furthermore, the users of web services must temporarily delegate some or all of their behalf. This results in the exposure of user privacy information by agents. We propose a delegation model for providing safety of web service and user privacy in ubiquitous computing environments. In order to provide safety of web service and user privacy, XML-based encryption and a digital signature mechanism need to be efficiently integrated. In this paper, we propose web service management server based on XACML, in order to manage services and policies of web service providers. For this purpose, we extend SAML to declare delegation assertions transferred to web service providers by delegation among agents.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.1
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• pp.81-92
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• 2009

Recently, there is a drastic increase in users interested in real-time multimedia services in the WLAN environment, as the demand of IEEE 802.11 WLAN-based services increases. However, the handoff delay based on 802.11i security policy is not acceptable for the seamless real-time multimedia services provided to MS frequently moving in the WLAN environment, and there is a possibility of DoS attacks against session key derivation process and handoff mechanism. In this paper, a secure and efficient handoff mechanism in the centralized WLAN environment is introduced to solve the security problems. The 4-way Handshake for both mutual authentication and session key derivation is replaced by the 2-way Reassociation process.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.6
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• pp.47-58
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• 2002

The access control techniques, which can control unauthorized members to access to multicast service, have not been studied very often while there are a lot of on-going study on secure multicast architecture, multicast key distribution and sender authentication scheme have been studied. Multi level access control scheme in multicast can be used in a remote secure conference or to provide graduated multimedia services to each customers. In fact, multicast network has its own virtual networks according to different security levels. However, Early schemes are not effective when it protects unauthorized access in multi-access network environment. Furthermore this scheme does not provide us with hierarchical access control mechanism. This paper, therefore, proposes hierarchical access control scheme to provide the effectiveness in network layer by security level comparison. And we also suggests hierarchical key distribution scheme for multi level access control in application layer and effective hierarchical key renewal scheme in dynamic multicast environment which is easy to join and leaving the multicast group.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.5
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• pp.59-71
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• 2005

A RFID (Radio Frequency Identification) system receives attention as the technology which can realize the ubiquitous computing environment. However, the feature of the RFID tags may bring about new threats to the security and privacy of individuals. Recently, Juels proposed the minimalist cryptography for very low-cost RFID tags, which is secure. but only under the impractical assumption such that an adversary is allowed to eavesdrop only the pre-defined number of sessions. In this paper, we propose a scheme to protect privacy for very low-cost RFID systems. The proposed protocol uses only bit-wise operations without my costly cryptographic function such as hashing, encryption which is secure which is secure against an adversary who is allowed to eavesdrop transmitted message in every session any impractical assumption. The proposed scheme also is more efficient since our scheme requires less datas as well as few number of computations than Juels's scheme.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.6
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• pp.1069-1080
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• 2022

Zero trust, which means never trust anything before verifying it, is emerging as a hot issue in security field. After authenticating users, zero trust establishes network boundaries so that only networks in the trusted range can be accessed. This concept is also consistent with the concept of SDP, which performs pre-verification and creates a network boundary with a dynamic firewall so that clients can access only as many as they have permission to connect. Therefore, we recommend the SDP model as an example of how zero trust can be achieved in a zero trust architecture. In this paper, we point out the areas where SDP needs to be modified for zero trust and suggest ways to overcome them. In addition, we propose an onboarding method, which is one of the processes for becoming an SDP entity, and present performance measurement results.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.7
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• pp.1060-1070
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• 2022

With the development of information technology, the size of the system has become larger and diversified, and the existing role-based access control has faced limitations. Blockchain technology is being used in various fields by presenting new solutions to existing security vulnerabilities. This paper suggests efficient role-based access control in a blockchain where the required gas and processing time vary depending on the access frequency and capacity of the storage. The proposed method redefines the role of reusable units, introduces a hierarchical structure that can efficiently reflect dynamic states to enhance efficiency and scalability, and includes user-centered authentication functions to enable cryptocurrency linkage. The proposed model was theoretically verified using Markov chain, implemented in Ethereum private network, and compared experiments on representative functions were conducted to verify the time and gas efficiency required for user addition and transaction registration. Based on this in the future, structural expansion and experiments are required in consideration of exception situations.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.5
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• pp.827-835
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• 2022

In order to use online financial services, user authentication technology is necessary. Password check through keyboard typing is the most common technique. However, since it became known that key stokes on the keyboard can be intercepted easily, many Internet banking services and easy payment services have adopted the virtual keyboard. However, contrary to the expectation that the virtual keyboard will be safe, there is a risk that key strokes on the virtual keyboard can be leaked. In this paper, we analyzed the possibility of password leaking on the virtual keyboard and presented a password leaking method using mouse event hooking and screen capture in PC operating system. In addition, we inspected the possibility of password leak attacks on several famous Korea Internet banking websites and simple payment services, and as a result, we verified that the password input method through the virtual keyboard in the PC operating system is not secure.