Key Management Method Research Articles

다중기기 시청환경을 지원하기 위한 SVC와 CAS 결합 기법

IPTV나 DTV에서 사용하는 CAS는 하나의 스트리밍으로 하나의 콘텐츠만을 전송하는 환경이지만 SVC와의 결합을 통해 사용자의 다양한 비디오 어플리케이션을 단일 스트리밍으로 지원하도록 개선할 수 있다. 이러한 환경에서는 효율성을 우선적으로 설계하여야 하며, 서비스 등급별 과금 정책을 위해 계층적 키 관리 기법의 적용이 필요하다. 본 논문에서는 CAS에 SVC를 적용하기 위해 고려해야할 점들에 대해 살펴보고 CAS를 통해 암호화된 SVC 콘텐츠를 전송하는 모듈을 제안한다. 제안하는 기법을 적용하면 단일 스트림을 사용하는 CAS 에서도 다중기기를 이용하여 콘텐츠를 시청할 수 있으며, 사용자에게 시청 화질에 따른 과금 부과가 가능하다. 제안하는 기법의 안전성은 CAS와 단방향 해시 함수의 안전성에 기반한다. 또한, 실험 결과 10%미만의 적은 오버헤드로 스트리밍 서비스 되는 SVC 콘텐츠를 안전하게 보호할 수 있다는 장점이 있다. CAS used in IPTV or DTV has an environment of sending single type of contents through single streaming. But it can be improved to support users' various video applications through single streaming by combining with SVC. For such an environment, efficiency should be firstly considered, and hierarchical key management methods for billing policy by service levels should be applied. This study aims to look into considerations to apply SVC to CAS and propose SVC encryption in CAS environment. The security of the proposed scheme is based on the safety of CAS and oneway hash function. If the proposed scheme is applied, scalability can be efficiently provided even in the encrypted contents and it is possible to bill users according to picture quality. In addition, the test results show that SVC contents given by streaming service with the average less than 10%overhead can be safely protected against illegal uses.

Comparison among different Cryptographic Algorithms using Neighborhood-Generated Keys

The prevention of information from unauthorized access is the main concern in the area of cryptography. There are various algorithms i.e. Elgamal, RSA, diffie Hellman, Knapsack are proposed with varying key length and key management methods. The size of encrypted message, key management method and algorithm efficiency is critical in respect of implementation in organizations that store large volumes of data. This paper proposes the comparison among various algorithms for different cryptography algorithms used in generating the neighborhood keys.

Reliable Key Management and Data Delivery Method in Multicast Over Wireless IPv6 Networks

Multicast is an efficient way to reduce the required bandwidth of transmitting data simultaneously to a group of users in wireless IPv6 networks. Nevertheless, multicast suffers from two main drawbacks which can be looked from two perspectives, namely security and QoS. With regard to security, the main challenge is to provide security protection to multicast data, which can be achieved by using a secure key management process. Considering a highly dense environment where connection of users to the network is changing frequently due to join or leave operations, key updating approach may burden a network devices with a huge amount of complex encryption/decryption processes. From the QoS perspective, multicast transmission over WLAN offers a tradeoff between the transmission rate and the coverage. The transmission rate of multicast is confined by the user with the lowest data rate in the group which is called fixed base rate problem. To address the above mentioned problems, we propose and implement a lightweight key management and data delivery scheme for multicast over wireless IPv6 networks. The proposed solution is envisaged to reduce the complexity of key updating, while at the same time is able to address the fixed base rate problem. The performance evaluation (by means of analytical and test-bed implementation) of the proposed key management method indicates its efficiency in reducing communication, computation, and storage costs, while maintaining both forward and backward securities. Moreover, the proposed data delivery method is able to improve the throughput and QoS, with low packet loss and transmission delay.

An Effective and Secure Key-Management Scheme for Hierarchical Access Control in E-Medicine System

Recently several hierarchical access control schemes are proposed in the literature to provide security of e-medicine systems. However, most of them are either insecure against 'man-in-the-middle attack' or they require high storage and computational overheads. Wu and Chen proposed a key management method to solve dynamic access control problems in a user hierarchy based on hybrid cryptosystem. Though their scheme improves computational efficiency over Nikooghadam et al.'s approach, it suffers from large storage space for public parameters in public domain and computational inefficiency due to costly elliptic curve point multiplication. Recently, Nikooghadam and Zakerolhosseini showed that Wu-Chen's scheme is vulnerable to man-in-the-middle attack. In order to remedy this security weakness in Wu-Chen's scheme, they proposed a secure scheme which is again based on ECC (elliptic curve cryptography) and efficient one-way hash function. However, their scheme incurs huge computational cost for providing verification of public information in the public domain as their scheme uses ECC digital signature which is costly when compared to symmetric-key cryptosystem. In this paper, we propose an effective access control scheme in user hierarchy which is only based on symmetric-key cryptosystem and efficient one-way hash function. We show that our scheme reduces significantly the storage space for both public and private domains, and computational complexity when compared to Wu-Chen's scheme, Nikooghadam-Zakerolhosseini's scheme, and other related schemes. Through the informal and formal security analysis, we further show that our scheme is secure against different attacks and also man-in-the-middle attack. Moreover, dynamic access control problems in our scheme are also solved efficiently compared to other related schemes, making our scheme is much suitable for practical applications of e-medicine systems.

IFRP: an intrusion/fault tolerant routing protocol for increasing resiliency and reliability in wireless sensor networks

Limitations of sensors cause routing and data sending to the base station become one of the challenging issues in wireless sensor networks WSNs. So far, many methods are proposed for routing in the WSNs, but security is not mentioned in the most of them. Moreover, the proposed secure routings either are used for specific attack or have a high overhead. In this paper, we present a new method for neighbour detection and key management, and introduce a routing called intrusion/fault tolerant routing protocol IFRP. The routing is switched from single path to multipath in the face of malicious behaviour by local warden technique LWT. Proposed protocol detects and isolates intruder or faulty nodes by utilising LWT and a centralised decision. Simulations show that the IFRP have a superior delivery ratio over the mechanisms with low overhead. Moreover, results illustrate that the method with extra overhead has very low delivery ratio improvement by just 1%.

Research on Urban Digital Governance Framework Based on Grid Management

Urban grid management (UGM), as a new urban digital governance pattern, has been applied in more and more Chinese cities in recent years. After analyzing the digital governance practices in Beijing - the key technology, management method, management procedure and implementation effect of the UGM pattern, we find that UGM pattern is capable of both simplifying administrative process and improving the government management efficiency, while the target of digital governance to provide quality public service and expand public participation has been ignored. Therefore, an urban digital governance framework based on grid management consisting of four modules and eight systems is put forward in this paper. This framework takes into account the improving government management efficiency, providing better public service and expanding democratic participation at the same time.

대규모 센서 네트워크에서 그룹을 기반으로 한 에너지 효율적인 클러스터키 관리 방안

Abstract The important issue that applies security key are secure rekeying, processing time and cost reduction. Because of sensor node's limited energy, energy consumption for rekeying affects lifetime of network. Thus it is necessary a secure and efficient security key management method. In this paper, I propose an energy efficient group-based cluster key management (EEGCK) in the large scale sensor networks. EEGCK uses five security key for efficient key management and different polynomial degree using security fitness function of sector, cluster and group is applied for rekeying and security processing. Through both analysis and simulation, I also show that proposed EEGCK is better than previous security management method at point of network energy efficiency. Key Words : large scale sensor networks, cluster key management, security fitness function, polynomial degree, five security key, lifetime of network, network energy efficiency * Corresponding Author : Jin-Su KimTel: +82-10-4553-8543 email: kjs8543@tu.ac.kr접수일 12년 08월 23일 수정일(1차 12년 09월 26일, 2차 12년 10월 05일) 게재확정일 12년 11월 08일

Centralized group key management mechanism for VANET

ABSTRACTThe vehicular ad hoc network (VANET) is a novel wireless network and suffers security threats as other networks. Information exchanged in the network might be stolen by malicious users, and some secure mechanisms are needed to provide the privacy. In VANET, the vehicles can be separated to different groups. When vehicles in the same group want to communicate with others, they can use the group key to protect the messages, and the privacy in the group communication is preserved. In this paper, we propose a group key management method with centralized key management scheme for VANET. In each group, there is a group leader, and the group leader will manage the members and the keys. By managing the group keys properly, the communication in the group can be secure. In the performance evaluation and analysis, our proposal provides better rekey mechanisms to related works and also achieves the forward secrecy and backward secrecy. Copyright © 2012 John Wiley & Sons, Ltd.

Multi-scale modeling on human intravascular cooling to induce brain hypothermia via circle of Willis

Therapeutic hypothermia has been the most effective therapy to treat serious cardiovascular and cerebrovascular diseases. Among them, intravascular cooling is identified as a most efficient approach to induce brain hypothermia. However until now, some key parameters and temperature management method for intravascular cooling are still not well addressed because of the complexity of human thermoregulation mechanism. Aiming at predicting temperature variation of tissues and organs in a more accurate way during therapeutic hypothermia, this study is dedicated to integrate the blood flow model in the circle of Willis together with the compartmental model for characterizing the heat and blood transport throughout the whole human body. According to the theoretical evaluation, the new model could well simulate the temperature response of the whole human body especially the brain under various cooling. Effects of different intervention site and cooling power to the hypothermia performance are discussed, which shows that carotid artery intervention is a more suitable therapeutic hypothermia method in comparison with femoral artery or femoral vein intervention. These results could help design controlling software for intravascular therapeutic hypothermia device in the near future.

An Efficient Key-Management Scheme for Hierarchical Access Control in E-Medicine System

In e-medicine system, the sharing of patients' medical histories scattered among medical institutions through the Internet is highly desirable. The most immediate cryptographic need certainly is an efficient key management method to solve dynamic access problems in a user hierarchy. In this paper, we propose a practical solution for dynamic access problem in a user hierarchy based on hybrid cryptosystems. When compared with Nikooghadam et al.'s scheme proposed most recently, the time complexity and the required storage space is reduced significantly. Moreover, it provides provable security, and is easy to implement. Therefore, our scheme is more suitable for e-medicine system.

SCCR: a generic approach to simultaneously achieve CCA security and collusion‐resistance in proxy re‐encryption

AbstractBy allowing a proxy to blindly perform meaningful transformations from one ciphertext to another, proxy re‐encryption (PRE) is an important cryptographic primitive in many applications, such as encrypted email forwarding and distributed file system. Due to its usefulness, various PRE schemes have been proposed; however, only one can simultaneously achieve chosen ciphertext security (CCA security) and collusion‐resistance. When such schemes are deployed, lack of CCA security will cause secret leaking, and lack of collusion‐resistance will cause non‐repudiation damage. In this paper, we propose a novel approach (denoted SCCR) to simultaneously achieve CCA security and collusion‐resistance in PRE, which faces daunting new challenges. We address these challenges by using CCA‐secure (2, 2) threshold cryptosystem to obtain public verifiability, and the method of key management in identity‐based encryption (IBE) to achieve collusion‐resistance. These two novel techniques have not been yet used in any previous PRE schemes. A unique characteristic of SCCR is that it is a generic construction which has more advantages than a concrete PRE scheme does. Copyright © 2009 John Wiley & Sons, Ltd.

Tree-based Multicast Key Management in ubiquitous computing environment

A Tree-based Multicast group Key Management (TMKM) protocol for ubiquitous computing is proposed to generate, distribute, and update the group key. The whole group is divided into the server layer and the user layer, and the user layer is further divided into subgroups. Every subgroup is initialised as a balanced binary tree. We employ hierarchical group key management method for the whole topology and centralised group key management method for subgroup, so TMKM takes advantage of centralised and distributed key group management. Compared with some other group key management protocols, TMKM shows higher superiority on security, scalability and computation complexity.

H.264/SVC에 대한 접근 제어 방법 및 키 관리 방법

CAS는 정당한 사용자만이 콘텐츠를 수신할 수 있도록 하는 수신 제어 시스템으로서, 최근 각광받고 있는 IPTV 등에서도 이를 이용하고 있다. H.264/SVC는 동일한 콘텐츠를 다양한 네트워크 환경과 단말기 성능에 따라 수신할 수 있도록 하는 표준 코딩 기법이다. 이 기법은 사용자가 수신 품질을 결정할 수 있도록 콘텐츠를 계층 구조로 구성한다. 그러므로 콘텐츠 제공자는 사용자가 요금을 지불한 품질의 콘텐츠만을 수신할 수 있도록 제어할 수 있어야 한다. 현재 사용되고 있는 CAS의 구조는 H.264/SVC 콘텐츠 제어에 적합하지 않다. 본 논문에서는 CAS 구조에서 H.264/SVC 콘텐츠 접근을 효율적으로 제어하기 위한 기법과 키관리 기법을 제안한다. CAS is an access control system by which only legal users can access contents. IPTV is a spotlighted system that uses CAS. H.264/SVC is a coding standard that provides a scalable coding method by which users who are in various network environments and have various devices can receive the contents. In this method, the contents are coded in a layered structure to make users choose the quality of the receiving contents. Therefore, contents provider should be able to control users to access only appropriate contents according to their subscriptions. The structure of CAS being employed in many applications is not suitable to control access for H.264/SVC. In this paper, we provide an efficient access control method and a key management method for H.264/SVC contents using CAS.

A Forward Authentication Key Management Scheme for Heterogeneous Sensor Networks

Key encryption technology is a basic technique for protecting the secrecy of transmitted data among sensor nodes in wireless sensor networks. However, sensor nodes are inherently limited by insufficient hardware resources such as memory capacity and battery lifetime. As a result, few current key management schemes are appropriate for wireless sensor networks. This paper proposes a new key management method that uses dynamic key management schemes for heterogeneous sensor networks. The proposed scheme loads a hash function into the base station, cluster heads, and sensor nodes. The cluster heads and sensor nodes then generate their own keychains to provide forward authentication in case of key changes, security breaches, key changes due to security breaches. The cluster heads and sensor nodes establish pairwise keys to ensure transmission secrecy. The proposed scheme decreases the number of keys required for sensor nodes and cluster heads and is robust to the following attacks: guessing attacks, replay attacks, man-in-the-middle attacks, node capture attacks, and denial-of-service attacks.

Efficient Provider Authentication for Bidirectional Broadcasting Service

Provider authentication is necessary in bidirectional broadcasting services, and a digital signature scheme is often used to prevent an adversary from attempting impersonation. The cost of secure signing key management is extremely high. In addition, the key has to be updated very often, since it is frequently used. The result is that the verification key also has to be updated very often, and its redistribution cost is huge. These costs are real and substantive problems, especially when the number of users is large. In this paper, we propose a system that dramatically reduces these costs. In the system, the signing key is updated, but the corresponding verification key does not have to be updated. This means that the signing key can be updated without any cost for redistributing the verification key and that the system is secure against the threat of signing key leakage, since the key can be frequently updated. Moreover, we propose a new key management method that divides a conventional key management server's role into two. The use of a key-insulated signature (KIS) scheme enables low-cost and more secure key management with two servers. Finally, to make a bidirectional broadcasting service more secure even if the signing key is leaked, we developed a new strong KIS scheme. We performed an experiment that assessed the cost of our strong KIS scheme and found that it is sufficiently low. Accordingly, a provider authentication system employing this scheme would be more efficient and would have lower key redistribution and network costs in comparison with conventional authentication systems.

클러스터 기반에서의 인증을 통한 안전한 키 관리 기법

클러스터 기반의 라우팅 기법에서의 안전한 데이터 통신을 위해서는 기존의 키 관리 방식은 적합하지 않다. 왜냐하면 클러스터 기반에서는 매 라운드 마다 클러스터 헤드가 변경되기 때문에, 안전한 통신을 위해 각 멤버 노드들과 인증이나 공유키 설정 단계를 거쳐야 한다. 또한 기존의 키 관리 메커니즘에서는 대부분 센서 네트워크 안의 모든 노드에 대해 이동성을 부여하지 않았기 때문에, 노드의 이동성을 고려하게 되면 안전한 통신을 위한 커다란 오버 헤드가 발생한다. 따라서 본 논문에서는 이동성과 새로운 노드의 삽입이 빈번한 경우에도 안전하고 효율적인 클러스터 기반에 적합한 키 관리 메커니즘을 제안한다. The previous key management methods are not appropriate for secure data communication in cluster-based routing scheme. Because cluster heads are elected in every round and communicate with the member nodes for authentication and share-key establishment phase in the cluster. In addition, there are not considered to mobility of nodes in previous key management mechanisms. In this paper, we propose the secure and effective key management mechanisim in the cluster-based routing scheme that if there are no share keys between cluster head and its nodes, we create the cluster key using authentication with base station or trust autentication and exchange the their information for a round.

Interference management and performance analysis of UMTS/HSPA+ femtocells

Femtocells are low-power cellular base stations that operate in licensed spectrum. They are typically deployed indoors to improve coverage and provide excellent user experience, including high data rates. Cellular operators benefit from reduced infrastructure and operational expenses for capacity upgrades and coverage improvements. Femtocells also bring unique challenges, such as unplanned deployment, user installation, restricted access, and interoperability with existing handsets and network infrastructure. Although femtocells may cause some interference to other users in the network, with the use of proper interference management techniques, this can be well controlled. We present interference management techniques for both downlink and uplink of femtocells operating based on 3GPP Release 7 standards (also known as HSPA+). Femtocell carrier selection and femtocell DL Tx power self-calibration are proposed as key interference management methods for downlink. For uplink interference management, adaptive attenuation at the femtocell and limiting the Tx power of the femtocell users are proposed. Different interference models and their analysis are presented. In addition, coverage performance and capacity results are presented to quantify the benefits of femtocells. We demonstrate that in addition to coverage enhancements, significant capacity improvements are achieved on both downlink and uplink when femtocells are deployed in 3G UMTS/HSPA+ networks.

SMOCK: A Scalable Method of Cryptographic Key Management for Mission-Critical Wireless Ad-Hoc Networks

Mission-critical networks show great potential in emergency response and/or recovery, health care, critical infrastructure monitoring, etc. Such mission-critical applications demand that security service be ldquoanywhere,rdquo ldquoanytime,rdquo and ldquoanyhow.rdquo However, it is challenging to design a key management scheme in current mission-critical networks to fulfill the required attributes of secure communications, such as data integrity, authentication, confidentiality, nonrepudiation, and service availability. In this paper, we present a self-contained public key-management scheme, a scalable method of cryptographic key management (SMOCK), which achieves almost zero communication overhead for authentication, and offers high service availability. In our scheme, a small number of cryptographic keys are stored offline at individual nodes before they are deployed in the network. To provide good scalability in terms of the number of nodes and storage space, we utilize a combinatorial design of public-private key pairs, which means nodes combine more than one key pair to encrypt and decrypt messages. We also show that SMOCK provides controllable resilience when malicious nodes compromise a limited number of nodes before key revocation and renewal.

Biometric Authentication for Border Control Applications

We propose an authentication methodology that combines multimodal biometrics and cryptographic mechanisms for border control applications. We accommodate faces and fingerprints without a mandatory requirement of (tamper-resistant) smart-card-level devices on e-passports for easier deployment. It is even allowable to imprint (publicly readable) bar codes on the passports. Additionally, we present a solution based on the certification and key management method to control the validity of passports within the current Public-Key Infrastructure (PKI) technology paradigm.

A practical approach to market risk analysis and control: empirical test of the Mexican foreign exchange and stock markets

The Mexican financial markets, like many other emerging markets, are generally portrayed as illiquid, volatile, segmented and politically unpredictable. Despite all these shortcomings, portfolio investments and trading activities in emerging markets have immense rewards for markets' participants. These investment alternatives may create unique expected return opportunities and substantial inherent risks. Risk measurement, management and control in such economies are in fact wearisome tasks; however, it may be addressed through art and science risk management practices. In this research paper, key market risk management methods and procedures that financial institutions, regulators and policymakers should consider in devising their daily market risk management objectives are examined and are adapted to the specific needs of emerging financial markets. The proper use of Value At Risk (VAR) and stress-testing methods are illustrated with real-world examples and practical reports of market risk analysis and control. The calculations and conclusions that are presented herein where applied to both, the Mexican foreign exchange and stock markets. To this end, several case studies were achieved with the objective of setting a practical framework of market risk measurement and control reports in addition to the inception of procedures for the setting of VAR's limits. The effects of hedging equity trading exposures with reciprocal foreign exchange trading positions were examined and quantified.