循环码的周期分布的新的计算公式

本文在［１］文的基础上进一步分析了循环码的周期分布的性质，给出了新的计算方法和公式，并且确定了一些熟知的循环码的周期分布。     

PVK的光致发光的电场下的猝灭

对PVK在电场调制下的光致发光现象进行了研究,发现在高场下光致发光强度会减弱,且存在一个阈值,在阈值以下发光强度随电增加缓慢减弱,在域值以上则在出发光强度迅速减弱的趋势。     

基于Zigbee的智能家居系统的设计的研究

本文重点分析了现代家居智能化系统的需要实现的基本功能,探讨了于Zigbee技术的家居智能控制系统的整个设计思路,从硬软件的角度解析了家居智能控制系统具体设计细节等。     

自然的就是最好的

事实上,很多物品的灵感来自于自然,专业一些的说法叫仿生。不过这种黎法似乎显得太过严肃和学术,对于那些生活中和身边的物品,称它们是向自然讨教得来的一种“比喻”更形象。     

合适的就是最好的

随着PC技术的发展,硬盘的容量和性能越来越高了,但是,该买什么样的硬盘,这是很多囊中羞涩的用户所困惑的,下面笔者就结合自己的经验跟大家介绍一下,如何选择一块合适自己的硬盘.     

细胞的内质网的超微结构

细胞的内质网呈网状遍布于细胞质内,所以也可称之为内质网膜系统。内质网是细胞的内膜系统的重要成分,在蛋白质合成,脂类合成和糖原代谢等方面起着重要作用。研究证明细胞内的许多膜性结构均来源于内质网,因而它在细胞的内膜系统中占有中心地位。内质网的微细结构的观察与研究对了解细胞的正常生理和病理改变具有重要意义。我们对培训的非洲绿猴肾上皮细胞(CV-1),人早幼粒白血病细胞(HL-60)、活检的人体胃粘膜细胞和胃癌细胞以及手术切除的人体结肠细胞和结肠癌细胞等数种细胞的内质网,应用电镜技术和光镜技术进行了观察与分析。     

测试用例的复用技术的研究

软件测试是确保软件质量的可靠手段,是软件开发过程中必不可少的重要环节。随着软件项目中各类干系人对软件质量的要求不断提高,软件测试作为保证软件质量的主要途径之一,其重要性越来越受重视。随着软件复杂性提高,软件测试的复杂性也不断提高,测试成本不断增加,同时软件复用技术也在不断发展,软件测试成本的提高和软件复用技术的发展,促使了软件测试复用技术的不断发展。测试复用技术在软件领域得到了广泛的应用,在某些行业软件中得到了很好的应用,比如证券行业。     

现场总线的的定义

现场总线以数字信号取代模拟信号，在3C技术即计算机（Computer）、控制（Control）、通信（Communication）的基础上，大量现场检测与控制的信息就地采集、就地处理、就地使用，     

Certificateless online/offline signcryption for the Internet of Things

The Internet of Things (IoT) is an emerging network paradigm that aims to obtain the interactions among pervasive things through heterogeneous networks. Security is an important task in the IoT. Luo et al. (Secur Commun Netw 7(10): 1560–1569, 2014) proposed a certificateless online/offline signcryption (COOSC) scheme for the IoT (hereafter called LTX). Unfortunately, Shi et al. showed that LTX is not secure. An adversary can easily obtain the private key of a user by a ciphertext. Recently, Li et al. proposed a new COOSC scheme (hereafter called LZZ). However, both LTX and LZZ need a point multiplication operation in the online phase, which is not suitable for resource-constrained devices. To overcome this weakness, we propose a new COOSC scheme and prove its security in the random oracle model. In addition, we analyze the performance of our scheme and show its application in the IoT.     

Secure communication in CloudIoT through design of a lightweight authentication and session key agreement scheme

Internet of Things (IoT) is a newly emerged paradigm where multiple embedded devices, known as things, are connected via the Internet to collect, share, and analyze data from the environment. In order to overcome the limited storage and processing capacity constraint of IoT devices, it is now possible to integrate them with cloud servers as large resource pools. Such integration, though bringing applicability of IoT in many domains, raises concerns regarding the authentication of these devices while establishing secure communications to cloud servers. Recently, Kumari et al proposed an authentication scheme based on elliptic curve cryptography (ECC) for IoT and cloud servers and claimed that it satisfies all security requirements and is secure against various attacks. In this paper, we first prove that the scheme of Kumari et al is susceptible to various attacks, including the replay attack and stolen-verifier attack. We then propose a lightweight authentication protocol for secure communication of IoT embedded devices and cloud servers. The proposed scheme is proved to provide essential security requirements such as mutual authentication, device anonymity, and perfect forward secrecy and is robust against security attacks. We also formally verify the security of the proposed protocol using BAN logic and also the Scyther tool. We also evaluate the computation and communication costs of the proposed scheme and demonstrate that the proposed scheme incurs minimum computation and communication overhead, compared to related schemes, making it suitable for IoT environments with low processing and storage capacity.     

Group and hierarchical key management for secure communications in internet of things

Different devices with different characteristics form a network to communicate among themselves in Internet of Things (IoT). Thus, IoT is of heterogeneous in nature. Also, Internet plays a major role in IoT. So, issues related to security in Internet become issues of IoT also. Hence, the group and hierarchical management scheme for solving security issues in Internet of Things is proposed in this paper. The devices in the network are formed into groups. One of the devices is selected as a leader of each group. The communication of the devices from each group takes place with the help of the leader of the corresponding group using encrypted key to enhance the security in the network. Blom's key predistribution technique is used to establish secure communication among any nodes of group. The hierarchy is maintained such that the security can be increased further, but the delay is increased as it takes time to encrypt at every level of hierarchy. Hence, the numbers of levels of hierarchy need to be optimized such that delay is balanced. Hence, this algorithm is more suitable for delay‐tolerant applications. The performance of the proposed Algorithm is evaluated and is proved to perform better when compared with the legacy systems like Decentralized Batch‐based Group Key Management Protocol for Mobile Internet of Things (DBGK).     

Security Enhanced Anonymous User Authenticated Key Agreement Scheme Using Smart Card

Nowadays, the password-based remote user authentication mechanism using smart card is one of the simplest and convenient authentication ways to ensure secure communications over the public network environments. Recently, Liu et al. proposed an efficient and secure smart card based password authentication scheme. However, we find that Liu et al.’s scheme is vulnerable to the off-line password guessing attack and user impersonation attack. Furthermore, it also cannot provide user anonymity. In this paper, we cryptanalyze Liu et al.’s scheme and propose a security enhanced user authentication scheme to overcome the aforementioned problems. Especially, in order to preserve the user anonymity and prevent the guessing attack, we use the dynamic identity technique. The analysis shows that the proposed scheme is more secure and efficient than other related authentication schemes.     

Hexagonal Clustered Trust Based Distributed Group Key Agreement Scheme in Mobile Ad Hoc Networks

Secure and efficient group communication among mobile nodes is one of the significant aspects in mobile ad hoc networks (MANETs). The group key management (GKM) is a well established cryptographic technique to authorise and to maintain group key in a multicast communication, through secured channels. In a secure group communication, a one-time session key is required to be shared between the participants by using distributed group key agreement (GKA) schemes. Due to the resource constraints of ad hoc networks, the security protocols should be communication efficient with less overhead as possible. The GKM solutions from various researches lacks in considering the mobility features of ad hoc networks. In this paper, we propose a hexagonal clustered one round distributed group key agreement scheme with trust (HT-DGKA) in a public key infrastructure based MANET environment. The proposed HT-DGKA scheme guarantees an access control with key authentication and secrecy. The performance of HT-DGKA is evaluated by simulation analysis in terms of key agreement time and overhead for different number of nodes. Simulation results reveal that the proposed scheme guarantees better performance to secure mobile ad hoc network. It is demonstrated that the proposed scheme possesses a maximum of 2250 ms of key agreement time for the higher node velocity of 25 m/s and lower key agreement overhead. Also, the HT-DGKA scheme outperforms the existing schemes in terms of successful message rate, packet delivery ratio, level of security, computation complexity, number of round, number of exponentiations and number of message sent and received that contribute to the network performance.

     

Attacks on and Countermeasures for Two RFID Protocols

Radio Frequency Identification (RFID) technology is expected to play a key role in the Internet of Things (IoT) and has applications in a wide variety of domains ranging from automation to healthcare systems. Therefore, the security and privacy of RFID communication is critical. In this paper, we analyze two recent RFID protocols proposed by researchers. Specifically we show that the ownership transfer protocol proposed by Wang et al., is vulnerable to tracing attacks while the mutual authentication protocol proposed by Cho et al. is vulnerable to key disclosure and backward traceable attacks. We propose secure improvements to these protocols to address the vulnerabilities, and improve the scalability of these schemes making them suitable for large-scale deployments.

     

一种适于受限资源环境的远程用户认证方案的分析与改进

该文讨论了Fang等人(2011)新近提出的一个安全高效的基于智能卡的远程用户口令认证方案,指出原方案无法实现所声称的抗离线口令猜测攻击,对平行会话攻击和已知密钥攻击是脆弱的,并且存在用户口令更新友好性差问题。给出一个改进方案,对其进行了安全性和效率分析。分析结果表明,改进方案弥补了原方案的安全缺陷,保持了较高的效率,适用于安全需求较高的资源受限应用环境。     

Fog-Sec: Secure end-to-end communication in fog-enabled IoT network using permissioned blockchain system

The technological integration of the Internet of Things (IoT)-Cloud paradigm has enabled intelligent linkages of things, data, processes, and people for efficient decision making without human intervention. However, it poses various challenges for IoT networks that cannot handle large amounts of operation technology (OT) data due to physical storage shortages, excessive latency, higher transfer costs, a lack of context awareness, impractical resiliency, and so on. As a result, the fog network emerged as a new computing model for providing computing capacity closer to IoT edge devices. The IoT-Fog-Cloud network, on the other hand, is more vulnerable to multiple security flaws, such as missing key management problems, inappropriate access control, inadequate software update mechanism, insecure configuration files and default passwords, missing communication security, and secure key exchange algorithms over unsecured channels. Therefore, these networks cannot make good security decisions, which are significantly easier to hack than to defend the fog-enabled IoT environment. This paper proposes the cooperative flow for securing edge devices in fog-enabled IoT networks using a permissioned blockchain system (pBCS). The proposed fog-enabled IoT network provides efficient security solutions for key management issues, communication security, and secure key exchange mechanism using a blockchain system. To secure the fog-based IoT network, we proposed a mechanism for identification and authentication among fog, gateway, and edge nodes that should register with the blockchain network. The fog nodes maintain the blockchain system and hold a shared smart contract for validating edge devices. The participating fog nodes serve as validators and maintain a distributed ledger/blockchain to authenticate and validate the request of the edge nodes. The network services can only be accessed by nodes that have been authenticated against the blockchain system. We implemented the proposed pBCS network using the private Ethereum 2.0 that enables secure device-to-device communication and demonstrated performance metrics such as throughput, transaction delay, block creation response time, communication, and computation overhead using state-of-the-art techniques. Finally, we conducted a security analysis of the communication network to protect the IoT edge devices from unauthorized malicious nodes without data loss.     

A Full Connectable and High Scalable Key Pre-distribution Scheme Based on Combinatorial Designs for Resource-Constrained Devices in IoT Network

Considering the internet of things (IoT), end nodes such as wireless sensor network, RFID and embedded systems are used in many applications. These end nodes are known as resource-constrained devices in the IoT network. These devices have limitations such as computing and communication power, memory capacity and power. Key pre-distribution schemes (KPSs) have been introduced as a lightweight solution to key distribution in these devices. Key pre-distribution is a special type of key agreement that aims to select keys called session keys in order to establish secure communication between devices. One of these design types is the using of combinatorial designs in key pre-distribution, which is a deterministic scheme in key pre-distribution and has been considered in recent years. In this paper, by introducing a key pre-distribution scheme of this type, we stated that the model introduced in the two benchmarks of KPSs comparability had full connectivity and scalability among the designs introduced in recent years. Also, in recent years, among the combinatorial design-based key pre-distribution schemes, in order to increase resiliency as another criterion for comparing KPSs, attempts were made to include changes in combinatorial designs or they combine them with random key pre-distribution schemes and hybrid schemes were introduced that would significantly reduce the design connectivity. In this paper, using theoretical analysis and maintaining full connectivity, we showed that the strength of the proposed design was better than the similar designs while maintaining higher scalability.

     

A novel authenticated group key agreement protocol for mobile environment

An authenticated group key agreement protocol allows a group of parties to authenticate each other and then determine a group key via an insecure network environment. In 2009, Lee et al. first adopted bilinear pairings to propose a new nonauthenticated group key agreement protocol and then extend it to an authenticated group key agreement protocol. This paper points out that the authenticated protocol of Lee et al. is vulnerable to an impersonation attack such that any adversary can masquerade as a legal node to determine a group key with the other legal nodes and the powerful node. This paper shall employ the short signature scheme of Zhang et al. to propose a new authenticated group key agreement protocol. The short signature scheme of Zhang et al. is proven to be secure against the adaptive chosen-message attacks in the random oracle model, so the proposed protocol can withstand the possible attacks. Besides, compared with the authenticated protocol of Lee et al., the proposed protocol is more secure and efficient.