http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Secure Group Communication with Dynamic Membership Change in Ad Hoc Networks
( Heeyoul Kim ) 한국인터넷정보학회 2011 KSII Transactions on Internet and Information Syst Vol.5 No.9
The importance of secure communication between only legitimate group members in ad hoc networks has been growing in recent years. Due to the ad hoc nature the scalability on dynamic membership change is a major concern. However, the previous models require at least O(log n) communication cost for key update per each membership change, which imposes a heavy burden on the devices. In this paper we present a scalable model that supports communication-efficient membership change in ad hoc networks by exclusionary keys and RSA functions. The multicast cost for key update is extremely low, that is O(1), and one-to-one communications occur mostly in neighboring devices.
Estimating Resident Registration Numbers of Individuals in Korea: Revisited
( Heeyoul Kim ),( Ki-woong Park ),( Daeseon Choi ),( Younho Lee ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.6
Choi et al's work [1] in 2015 demonstrated that the resident registration numbers (RRNs) of individuals could be conveniently estimated through their personal information that is ordinarily disclosed in social network services. As a follow-up to the study, we introduce the status of the RRN system in Korea in terms of its use in the online environment, particularly focusing on their secure use. We demonstrate that it is still vulnerable against a straightforward attack. We establish that we can determine the RRNs of the current president Moon Jae-In and the world-class singer PSY.
Securing Android In-app Billing Service against Automated Attacks
Heeyoul Kim,Sang-won Kim 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.7
In-app Billing service in Android enables the application developers sell digital content from inside the applications. To enhancing security of these applications, there have been presented security guidelines and various security techniques. However, recent automated attacks on every application in a device make the user of the device to get valuable content without paying for them. In this paper we present a novel approach to secure Android In-app Billing service against such automated attacks by detecting these attacks. Before completing the purchase, our approach performs a test to check whether there is an attempt to bypass a legitimate payment process. It is simple so as to be applied easily, and it effectively detects attacks by testing the signature verification process. With this approach, known automated attacks could be detected successfully.
( Heeyoul Kim ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.3
Android platform provides In-app Billing service for purchasing valuable items inside mobile applications. However, it has become a major target for attackers to achieve valuable items without actual payment. Especially, application developers suffer from automated attacks targeting all the applications in the device, not a specific application. In this paper, we propose a novel scheme detecting automated attacks with probabilistic tests. The scheme tests the signature verification method in a non-deterministic way, and if the method was replaced by the automated attack, the scheme detects it with very high probability. Both the analysis and the experiment result show that the developers can prevent their applications from automated attacks securely and efficiently by using of the proposed scheme.
A Group Key based Security Model for Big Data System
Heeyoul Kim 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.8
Recently Big data is in the spotlight and several NoSQL systems have been appeared in order to process large scale data. Among them Cassandra provides high scalability and availability with internal cluster structure. However, it does not provide enough security functionalities, especially transferred messages between internal cluster nodes are easily exposed by outside adversaries. In this paper a group key based security model for Cassandra is proposed. Cluster membership authentication and message confidentiality is provided by using of the group key, and the key is efficiently updated by decentralized approach where the cluster is divided into several subgroups considering Cassandra structure. Our model contributes preventing Cassandra cluster from illegal outside access attempts.
김희열(Heeyoul Kim),이윤호(Younho Lee),박용수(Yongsu Park),윤현수(Hyunsoo Yoon) 한국정보과학회 2007 정보과학회논문지 : 시스템 및 이론 Vol.34 No.11·12
다양한 종류의 데이타 스트림과 다양한 권한을 가지는 사용자들을 위한 그룹 통신을 위해서는 접근 제어(access control)가 필수적이다. 동일한 접근 권한을 가지는 그룹 멤버들은 하나의 클래스에 속하게 되며, 이러한 클래스들은 주어진 접근 관계를 표현한 하나의 계층을 구성한다. 그리고 각 클래스에는 하나의 비밀키가 할당된다. 기존의 기법들에서는 계층으로부터 하나의 논리적 키 트리를 생성하고 각 사용자는 항상 자신이 접근할 수 있는 모든 클래스의 키를 관리하는 방식, 즉 선행적(proactive)인 방식이었다. 하지만, 계층의 규모가 큰 경우에 사용자가 키를 저장하기 위한 공간이 늘어나고 키 갱신을 위한 메시지 또한 커진다는 단점을 가진다. 그리고 대부분의 경우 사용자는 극히 일부의 스트림만을 동시에 접근하게 되며, 이를 위해 모든 키를 지속적으로 갱신하는 것은 낭비가 된다. 본 논문에서는 이를 고려한 반응적 (reactive)인 방식의 키 관리 기법을 제안한다. 각 사용자는 자신이 속한 서브그룹의 키만을 관리하며 다른 키가 필요한 경우에만 자신의 키와 공개 파라미터를 이용해서 해당 키를 추출하게 된다. 이로 인해 키갱신을 위한 비용이 줄어들게 되고, 특히 접근 관계가 복잡하고 규모가 큰 그룹에 대해 좋은 성능을 가진다. 그리고 접근 관계가 변하는 경우, 이를 쉽게 반영할 수 있다는 장점을 가진다. In the group communication which has multiple data streams and various access privileges, it is necessary to provide group access control. The group members having the same access privilege are classified into one class, and the classes form a hierarchy based on the access relations. Then each class is assigned to a secret key. In the previous schemes, a single logical key graph is constructed from the hierarchy and each member always holds all secret keys of the classes he can access in the proactive manner. Thus, higher-privileged members hold more keys then lowerprivileged members. However, if the hierarchy is large, each member manages too many keys and the size of multicast message in rekeying increases in proportion to the size of the hierarchy. Moreover, most of the members access a small portion of multiple data streams simultaneously. Therefore, it is redundant to receive rekeying message and update the keys in which he is not currently interested. In this paper, we present a new key management scheme that takes a reactive approach in which each member obtains the key of a data stream only when he wants to access the stream. Each member holds and updates only the key of the class he belongs. If he wants to get the key of other class, he derives it from his key and the public parameter. Proposed scheme considerably reduces the costs for rekeying, especially in the group where access relations are very complex and the hierarchy is large. Moreover, the scheme has another advantage that it easily reflects the change of access relations.