Secure Communication

The tremendous advances in wireless networks, mobile computing, and sensor networks, along with the rapid growth of small, portable and powerful computing devices, offers more and more opportunities for pervasive computing and communications. This topic deals with cutting-edge research in various aspects related to the theory and practice of mobile computing or wireless and mobile networking. These aspects include architectures, algorithms, networks, protocols, modeling and performance issues, data management, ...

Presently, mobile handheld device has successfully replaced traditional telephone to become the most popular wireless communication tools. Mobile Short Message Service (SMS) and Multimedia Message Service (MMS) fulfill almost all the user requirements as an effective communication and information delivering service. Since SMS/MMS become so popular on daily communication, there is a demand to communicate or exchange confidential information in a secure environment. Public Key Infrastructure (PKI) is a proven solution, which using pairing of key, for secure communication encryption. In this paper, M-PKI is introduced to provide PKI encryption to the mobile SMS and MMS.

A peer-to-peer database management system(P2PDBMS) is a collection of autonomous data sources, called peers. In this system each peer augments a conventional database management system with an inter-operability layer (i.e. mappings/policies) for sharing data and services. Peers exchange data in a pair-wise fashion on-the-fly in response to a query without any centralized control. Generally, the communication link between two peers is insecure and peers create a temporary session while exchanging data. When peers exchange highly confidential data between them over an insecure communication network, such as the Internet, the data might be trapped and disclosed by the intruders. In a P2PDBMS there is no centralized control for data exchange, hence we cannot assume any central third party security infrastructure (e.g. PKI) to protect confidential data. So far, there is currently no available/existing security protocol for secured data exchange in P2PDBMS. In this paper we propose three models for secure data exchange in P2PDBMSs and the corresponding security protocols. The proposed protocol allows the peers to compute their secret session keys dynamically during data exchange based on the policies between them. Our proposed protocol is robust against the man-in-the middle attack, the masquerade attack, and the reply attack.

Internet was designed for network services without any intention for secure communication. Exponential growth of internet and its users have developed an era of global competition and rivalry. Denial of service attack by multiple nodes is capable of disturbing the services of rival servers. The attack can be for multiple reasons e. g. extortion or to beat the rivals. Peer

This paper discusses the concept of a virtual digital forensic laboratory, which incorporates networked examination and storage machines, secure communications, multi-factor authentication, role-based access control, and case management and digital asset management systems. Laboratory activities such as the examination, storage and presentation of digital evidence can be geographically distributed and accessed over a network by users with the appropriate credentials. The advantages of such a facility include reduced costs through shared resources and the availability of advanced expertise for specialized cases.

All-optical digital circuits based on loop memories are demonstrated. These circuits are a variable optical buffer, an optical random access memory, an optical shift register, and an optical linear feedback shift register. Buffers are employed in network nodes to solve the contentions without loosing information. Shift registers are used for error detection and correction techniques. Linear feedback shift registers are employed for generation of pseudo-random bit sequences, data scrambling, and encryption/decryption of information in secure communication systems. Since the role of optical processing is gradually increasing within the communication systems, the possibility to store information directly in the optical domain can lead to a systems simplification and to a performance improvement. In order to make the schemes suitable for practical applications, optical integration is necessary. The use of semiconductor optical amplifier as gain element into the memory loop allows all the proposed schemes to be integrated.

Secure communication in distributed systems is notoriously hard to achieve due to the variety of attacks an adversary can mount, based on message interception, modification, redirection, eavesdropping or, even more subtly, on traffic analysis. In the literature on process calculi, traditional solutions to the problem either draw on low-level cryptographic primitives, as in the spi or applied-pi calculi, or rely on very abstract, and hard-to-implement, mechanisms to hide communication by means of private channels, as in the pi-calculus. A more recent line of research follows a different approach, aimed at identifying security primitives adequate as high-level programming abstractions, and at the same time well-suited for security analysis and verification in adversarial settings. The present paper makes a step further in that direction. We develop a calculus of secure communication based on core abstractions that support concise, high-level programming idioms for distributed, security-sensitive applications, and at the same time are powerful enough to express a full-fledged adversarial setting. Drawing on this calculus, we investigate reasoning methods for security based on the long-established practice by which security properties are defined in terms of behavioral equivalences. We give a co-inductive characterization of behavioral equivalence, in terms of bisimulation, and develop powerful up-to techniques to provide simple coinductive proofs. We illustrate the adequacy of the model with several security laws for secrecy and authentication.

Presently, mobile handheld device has successfully replaced traditional telephone to become the most popular wireless communication tools. Mobile Short Message Service (SMS) and Multimedia Message Service (MMS) fulfill almost all the user requirements as an effective communication and information delivering service. Since SMS/MMS become so popular on daily communication, there is a demand to communicate or exchange confidential information in a secure environment. Public Key Infrastructure (PKI) is a proven solution, which using pairing of key, for secure communication encryption. In this paper, m–PKI is introduced to provide PKI encryption to the mobile SMS and MMS. This new approach allows the end-user to send private and classified message via SMS. The key pair generation and distribution are performed by the Certificate Authority (CA). The size of the key pair are studied and decided by the tradeoff between performance and security.

The appealing feature of quantum key distribution (QKD), from a cryptographic viewpoint, is the ability to prove the information-theoretic security (ITS) of the established keys. As a key establishment primitive, QKD however does not provide a standalone security service in its own: the secret keys established by QKD are in general then used by a subsequent cryptographic applications for which the requirements, the context of use and the security properties can vary. It is therefore important, in the perspective of integrating QKD in security infrastructures, to analyze how QKD can be combined with other cryptographic primitives.The purpose of this survey article, which is mostly centered on European research results, is to contribute to such an analysis. We first review and compare the properties of the existing key establishment techniques, QKD being one of them. We then study more specifically two generic scenarios related to the practical use of QKD in cryptographic infrastructures: 1) using QKD as a key renewal technique for a symmetric cipher over a point-to-point link ; 2) using QKD in a network containing many users with the objective of offering any-to-any key establishment service. We discuss the constraints as well as the potential interest of using QKD in these contexts. We finally give an overview of challenges relative to the development of QKD technology that also constitute potential avenues for cryptographic research.

Security services based on cryptographic mechanisms assume keys to be distributed prior to secure communications. The secure management of these keys is one of the most critical elements when integrating cryptographic functions into a system, since any security concept will be ineffective if the key management is weak. This paper approaches the problem of key management in a modular and hierarchical manner. It discusses key management security requirements, deals with generic key management concepts and design criteria, describes key management services and building blocks, as well as key management facilities, key management units, and their interrelationship.

Auf den letzten Seiten ihrer Studie Political Community and the North Atlantic Area (1969) geben die Autoren um Karl W. Deutsch ihrer Hoffnung Ausdruck, die NATO werde in Zukunft mehr sein als ein rein militärisches Bündnis. Über die wechselseitige politische und militärische Unterstützung hinaus sollten die Mitgliedsländer zu einer nordatlantischen politischen Gemeinschaft heranwachsen, auf deren Gebiet Konflikte und Kriege aufgrund gemeinsamer Erfahrungen, Werte und Erwartungen zunehmend unwahrscheinlich werden. Dieser Transformationsprozess beruhe weniger auf den militärischen Kapazitäten des Verteidigungsbündnisses als vielmehr auf der Entwicklung einer „gesellschaftlichen Gemeinschaft“ (Talcott Parsons). „This indicates that opportunities to integrate the North Atlantic area do not necessarily depend upon the continuation of a Soviet military threat, although that threat does seem to have helped toward greater unity“ (Deutsch u.a. 1957: 202).

Two-way identity authentication is the basis of secure communication in a distributed application environment. A trusted third party (TTP) is needed while PKI is not applicable, and the design of authentication protocols with TTP is a complicate and challenging task. This paper examines the characteristics of the security of authentication protocols with TTP, summarizes the essential factors of session key

In this paper, a new hyperchaotic system is presented by adding a nonlinear controller to the three-dimensional autonomous chaotic system. The generated hyperchaotic system undergoes hyperchaos, chaos, and some different periodic orbits with control parameters changed. The complex dynamic behaviors are verified by means of Lyapunov exponent spectrum, bifurcation analysis, phase portraits and circuit realization. The Multisim results of the hyperchaotic circuit were well agreed with the simulation results.

This paper introduces a new 3-D quadratic autonomous system, which can generate two coexisting single-wing chaotic attractors and a pair of diagonal double-wing chaotic attractors. More importantly, the system can generate a fourwing chaotic attractor with very complicated topological structures over a large range of parameters. Some basic dynamical behaviors and the compound structure of the new 3-D system are investigated. Detailed bifurcation analysis illustrates the evolution processes of the system among two coexisting sinks, two coexisting periodic orbits, two coexisting single-wing chaotic attractors, major and minor diagonal double-wing chaotic attractors, and a four-wing chaotic attractor. Poincaré-map analysis shows that the system has extremely rich dynamics. The physical existence of the fourwing chaotic attractor is verified by an electronic circuit. Finally, spectral analysis shows that the system has an extremely broad frequency bandwidth, which is very desirable for engineering applications such as secure communications.

Security has become paramount in modern software services as more and more security breaches emerge, impacting final users and organizations alike. Trends like the Microservice Architecture bring new security challenges related to communication, system design, development, and operation. The literature presents a plethora of security-related solutions for microservices-based systems, but the spread of information difficult practitioners' adoption of novel security related solutions. In this study, we aim to present a catalogue and discussion of security solutions based on algorithms, protocols, standards, or implementations; supporting principles or characteristics of information security, considering the three possible states of data, according to the McCumber Cube. Our research follows a Systematic Literature Review, synthesizing the results with a meta-aggregation process. We identified a total of 30 primary studies, yielding 75 security solutions for the communication of microservices.

Modern industrial communication networks are increasingly based on open protocols and platforms that are also used in the office IT and Internet environment. This reuse facilitates development and deployment of highly connected systems, but also makes the communication system vulnerable to electronic attacks. This paper gives an overview of IT security issues in industrial automation systems which are based on open communication systems. First, security objectives, electronic attack methods, and the available countermeasures for general IT systems are described. General security objectives and best practices are listed. Particularly for the TCP/IP protocol suite, a wide range of cryptography-based secure communication protocols is available. The paper describes their principles and scope of application. Next, we focus on industrial communication systems, which have a number of security-relevant characteristics distinct from the office IT systems. Confidentiality of transmitted data may not be required; however, data and user authentication, as well as access control are crucial for the mission critical and safety critical operation of the automation system. As a result, modern industrial automation systems, if they include security measures at all, emphasize various forms of access control. The paper describes the status of relevant specifications and implementations for a number of standardized automation protocols. Finally, we illustrate the application of security concepts and tools by brief case studies describing security issues in the configuration and operation of substations, plants, or for remote access.

Wireless sensor networks will be widely deployed in the near future. While much research has focused on making these networks feasible and useful, security has received little attention. We present a suite of security protocols optimized for sensor networks: SPINS. SPINS has two secure building blocks: SNEP and µTESLA. SNEP includes: data confidentiality, two-party data authentication, and evidence of data freshness. µTESLA provides authenticated broadcast for severely resource-constrained environments. We implemented the above protocols, and show that they are practical even on minimal hardware: the performance of the protocol suite easily matches the data rate of our network. Additionally, we demonstrate that the suite can be used for building higher level protocols.

History indicates that the security community commonly takes a divide-and-conquer approach to battling malware threats: identify the essential and inalienable components of an attack, then develop detection and prevention techniques that directly target one or more of the essential components. This abstraction is evident in much of the literature for buffer overflow attacks including, for instance, stack protection and NOP sled detection. It comes as no surprise then that we approach shellcode detection and prevention in a similar fashion. However, the common belief that components of polymorphic shellcode (e.g., the decoder) cannot reliably be hidden suggests a more implicit and broader assumption that continues to drive contemporary research: namely, that valid and complete representations of shellcode are fundamentally different in structure than benign payloads. While the first tenet of this assumption is philosophically undeniable (i.e., a string of bytes is either shellcode or it is not), truth of the latter claim is less obvious if there exist encoding techniques capable of producing shellcode with features nearly indistinguishable from non-executable content. In this paper, we challenge the assumption that shellcode must conform to superficial and discernible representations. Specifically, we demonstrate a technique for automatically producing English Shellcode, transforming arbitrary shellcode into a representation that is superficially similar to English prose. The shellcode is completely self-containedi.e., it does not require an external loader and executes as valid IA32 code)-and can typically be generated in under an hour on commodity hardware. Our primary objective in this paper is to promote discussion and stimulate new ideas for thinking ahead about preventive measures for tackling evolutions in code-injection attacks.

It has been recently investigated that the jerk dynamical systems are the simplest ever systems, which possess variety of dynamical behaviors including chaotic motion. Interestingly, the jerk dynamical systems also describe various phenomena in physics and engineering such as electrical circuits, mechanical oscillators, laser physics, solar wind driven magnetosphere ionosphere (WINDMI) model, damped harmonic oscillator driven by nonlinear memory term, biological systems etc. In many practical situations chaos is undesirable phenomenon, which may lead to irregular operations in physical systems. Thus from a practical point of view, one would like to convert chaotic solutions into periodic limit cycle or fixed point solutions. On the other hand, there has been growing interest to use chaos profitably by synchronizing chaotic systems due to its potential applications in secure communication. In this paper, we have made a thorough investigation of synchronization of identical chaotic jerk dynamical systems by implementing three well-known techniques: (i) Pecora-Carroll (PC) technique, (ii) Feedback (FB) technique and (iii) Active Passive decomposition (APD). We have given a detailed review of these techniques followed by the results of our investigations of identical synchronization of chaos in jerk dynamical systems. The stability of identical synchronization in all the aforesaid methods has also been discussed through the transversal stability analysis. Our extensive numerical calculation results reveal that in PC and FB techniques the x-drive configuration is able to produce the stable identical synchronization in all the chaotic jerk dynamical systems considered by us (except for a few cases), however y-drive and z-drive configurations do not lead to the stable identical synchronization. For the APD approach, we have suggested a generalized active passive decomposition, which leads to the stable identical synchronization without being bothered about the specific form of the jerk dynamical system. Several other active passive decompositions have also been listed with their corresponding conditional Lyapunov exponents to achieve the stable identical synchronization in various chaotic jerk dynamical systems.

This paper presents an efficient identity-based key exchange protocol based on the difficulty of computing a Elliptic Curve Discrete Logarithm Problem. As compared with the previously proposed protocols, it has better performance in terms of the computational cost and the communication steps. Key exchange protocols allow two parties communicating over a public network to establish a common secret key called session key to encrypt the communication data. Due to their significance by in building a secure communication channel, a number of key exchange protocols have been suggested over the years for a variety of settings.The proposed key exchange protocol provides implicit key authentication as well as the desired security attributes of an authenticated key exchange protocol.

Coupling of distributed computer resources connected by a high speed network to one virtual computer is the basic idea of a metacomputer. Access to the metacomputer should be provided by an intuitive graphical user interface (GUI), ideally WWW based. This paper presents a metacomputer architecture using a Java based GUI. The concept will be discussed with regard to security, communication, scalability, and the integration into existing frameworks.

In this paper, a new type of generalized Q-S ͑lag, anticipated, and complete͒ time-varying synchronization is defined. Adaptive Q-S ͑lag, anticipated, and complete͒ time-varying synchronization and parameters identification of uncertain delayed neural networks have been considered, where the delays are multiple time-varying delays. A novel control method is given by using the Lyapunov functional method. With this new and effective method, parameters identification and Q-S ͑lag, anticipated, and complete͒ time-varying synchronization can be achieved simultaneously. Simulation results are given to justify the theoretical analysis in this paper.

Transportation networks are high-value targets for terrorists and criminals. They are widely accessible, visible, attract intense media attention, and have a significant degree of government ownership. Since the 9/11 terrorist attack in 2001, transportation networks have been the focus of increasing security improvements worldwide. Much of the analytical work with respect to improved security of transportation networks has been related to the costs of the security improvements. Benefits have largely been ignored or described in general terms of community safety or the risk of terrorism of trade flows. This analysis provides a qualitative analysis of the benefits of security. An economic framework is used as a guide to develop a taxonomy of security benefits in four dimensions: sovereignty protection, terrorism prevention, interdiction of illegal activities, and personal security. Direct and indirect benefits are identified and classified as tangible and intangible. The analysis shows that the benefits of transportation security measures are often more subtle and pervasive than simply providing a safer and more secure community.

... Fasee Ullah, Masood Ahmad, Masood Habib, Jawad Muhammad Department of Computer Sciences City ... One of the early encouraging steps towards sensor network architecture is Polastre et al. ... Aim of this protocol to solve different key issues exchange during communication ...

There is a need to quantify system properties methodically. Dependability and security models have evolved nearly independently. Therefore, it is crucial to develop a classification of dependability and security models which can meet the requirement of professionals in both fault-tolerant computing and security community. In this paper, we present a new classification of dependability and security models. First we present

1 Associate Professor of International Relations at the Hebrew University of Jerusalem. He is the author of numerous articles and books, including The Power Ideology (University of California Press, 1987), Progress in Postwar International Relations (Columbia University Press, ...

The emergence of the Internet as a trusted medium for commerce and communication has made cryptography an essential component of modern information systems. Cryptography provides the mechanisms necessary to implement accountability, accuracy, and confidentiality in communication. As demands for secure communication bandwidth grow, efficient cryptographic processing will become increasingly vital to good system performance.

South America’s security agenda demands the simultaneous management of domestic crises, interstate conflicts and transnational threats. Though located at different systemic levels (national, international, transnational), the three conflict clusters are often interrelated and tend to overlap in the region’s border areas. The region’s policy makers, aware of this highly complex agenda and in spite of their striking differences, have tended

Near Future on-board Telemetry, Tracking and Command (TT&C) equipment for secure communications will likely adopt Frequency Hopping (FH) instead of Direct Sequence (DS) Spread Spectrum (SS) techniques. As far as TT&C systems will have to cope with jammer-to-signal power ratios higher than 50 dB, classical DS approaches must be abandoned in favour of more robust FH solutions. In the following paper we present an overview of synchronization, channel coding and modulation issues for next generation anti-jamming TT&C transponder under study and design at Alcatel Alenia Space -Italy (AAS-I).

Synchronization of chaotic systems is important because it might be useful in some type of private communications. In this paper, the phenomenon of Chaos that produced in the case of autonomous New Lorenz-like attractor circuit, have been studied extensively. The initial study of this work also includes some of the most well-known tools of nonlinear dynamics, such as the Lyapunov exponents and the Poincaré map. Furthermore, the use of this type of chaotic circuit in the connection substitution synchronization method is presented in details. After conducting the analysis of the proposed synchronization scheme, the use of such an autonomous chaotic circuit as a signal modulation in secure communication systems, has been examined. Finally, numerical simulations by using MATLAB 380 Aceng Sambas et al. 2010, as well as implementation of circuit simulations by using MultiSIM 10.0, has been performed in this work.

Presently, mobile handheld device has successfully replaced traditional telephone to become the most popular wireless communication tools. Mobile Short Message Service (SMS) and Multimedia Message Service (MMS) fulfill almost all the user requirements as an effective communication and information delivering service. Since SMS/MMS become so popular on daily communication, there is a demand to communicate or exchange confidential information in a secure environment. Public Key Infrastructure (PKI) is a proven solution, which using pairing of key, for secure communication encryption. In this paper, m–PKI is introduced to provide PKI encryption to the mobile SMS and MMS. This new approach allows the end-user to send private and classified message via SMS. The key pair generation and distribution are performed by the Certificate Authority (CA). The size of the key pair are studied and decided by the tradeoff between performance and security.

It has been recently investigated that the jerk dynamical systems are the simplest ever systems, which possess variety of dynamical behaviors including chaotic motion. Interestingly, the jerk dynamical systems also describe various phenomena in physics and engineering such as electrical circuits, mechanical oscillators, laser physics, solar wind driven magnetosphere ionosphere (WINDMI) model, damped harmonic oscillator driven by nonlinear memory term,

advantageously only if the property of chaotic systems is suitably exploited. Chaos communication has been studied for only a little more than a decade while traditional communication schemes have been developed for nearly a century. The hope was (and still is) that for some application chaotic communication will prove to be better than traditional communication. Yet, after one decade of research, in most cases chaos communication did not take the place of traditional communication schemes. As far as communication efficiency is concerned, chaotic communication schemes are typically less efficient than their traditional counterpart. Still, the main advantage of chaotic communication schemes is for analogy implementation of secure communication. In traditional communication schemes data has to be digitized before encryption takes place. This is due to the fact that traditional encryption is based on discrete number theory. In this paper we study the performance of Differential Chaos Shift Key (DCSK) modulation and we compare it to BPSK modulation, a new application of DCSK modulation is presented (transmission of the image).

In recent years, a large amount of work on chaos-based cryptosystems have been published. However many of the proposed schemes fail to explain or do not possess a number of features that are fundamentally important to all kind of cryptosystems. As a result, many proposed systems are difficult to implement in practice with a reasonable degree of security. Likewise, they are seldom accompanied by a thorough security analysis. Consequently, it is difficult for other researchers and end users to evaluate their security and performance. This work is intended to provide a common framework of basic guidelines that, if followed, every new cryptosystem would benefit from. The suggested guidelines address three main issues: implementation, key management, and security analysis, aiming at assisting designers of new cryptosystems to present their work in a more systematic and rigorous way to fulfill some basic cryptographic requirements. Meanwhile, several recommendations are made regarding some practical aspects of analog chaos-based secure communications, such as channel noise, limited bandwith, and attenuation.

In recent years, a large amount of work on chaos-based cryptosystems have been published. However many of the proposed schemes fail to explain or do not possess a number of features that are fundamentally important to all kind of cryptosystems. As a result, many proposed systems are difficult to implement in practice with a reasonable degree of security. Likewise, they are seldom accompanied by a thorough security analysis. Consequently, it is difficult for other researchers and end users to evaluate their security and performance. This work is intended to provide a common framework of basic guidelines that, if followed, every new cryptosystem would benefit from. The suggested guidelines address three main issues: implementation, key management, and security analysis, aiming at assisting designers of new cryptosystems to present their work in a more systematic and rigorous way to fulfill some basic cryptographic requirements. Meanwhile, several recommendations are made regarding some practical aspects of analog chaos-based secure communications, such as channel noise, limited bandwith, and attenuation.

Security of information has become a major issue during the last decades. New algorithms based on chaotic maps were suggested for protection of different types of multimedia data, especially digital images and videos in this period. However, many of them fundamentally were flawed by a lack of robustness and security. For getting higher security and higher complexity, in the current paper, we introduce a new kind of symmetric key block cipher algorithm that is based on tripled chaotic maps. In this algorithm, the utilization of two coupling parameters, as well as the increased complexity of the cryptosystem, make a contribution to the development of cryptosystem with higher security. In order to increase the security of the proposed algorithm, the size of key space and the computational complexity of the coupling parameters should be increased as well. Both the theoretical and experimental results state that the proposed algorithm has many capabilities such as acceptable speed and complexity in the algorithm due to the existence of two coupling parameters and high security. Note that the ciphertext has a flat distribution and has the same size as the plaintext. Therefore, it is suitable for practical use in secure communications.

The Kerberos-One-Time protocol is a key distribution protocol promoted for use with Javacards to provide secure communication over the GSM mobile phone network. From inspection we suspected a replay attack was possible on the protocol. To check this, we formally specified the protocol using Object-Z and then analysed its behaviour in the presence of an attacker using the Symbolic Analysis Laboratory's model checker. To produce accurate results efficiently, our formalism included an abstraction of the protocol's data structures that captured just those characteristics that we believed made the protocol vulnerable. Ultimately, the model checker's analysis confirmed our suspicions about the protocol's weakness.

The combination of physics, mathematics, and computer science in quantum computing has developed from a visionary idea to one of the most fascinating and promising areas of quantum mechanics in the past two decades. Research in the field of quantum cryptography promises extremely fast, robust, and impenetrable electronic and photonic security; almost unbreakable! Moreover, the long standing eavesdropping problem of the "man in the middle" attack may finally be solved once and for all. As computing power increases, and as hackers and attackers become more sophisticated, it is feared that sooner or later, traditional cryptography based on mathematically intractable algorithms may be no match for parallelized quantum based processors. For this reason, quantum cryptography, based on the laws of quantum statistical mechanics provides a welcome solution to this fear. This paper explores the basic tenets of quantum cryptography and how the mathematical principles therein apply to the quantum key distribution problem; a central concern in the implementation of quantum cryptography in distributed networks. The quantum key distribution protocol implemented in BB84 protocol is also described and compared to traditional cryptographic systems. A short overview of recent commercial implementations of quantum cryptography is presented with the encountered successes and limitations discussed. This paper explores the development of quantum networks, from the onset of the development of secure communication based on quantum cryptography and concludes with a brief outline of the key challenges facing quantum cryptography implementation in wireless applications and long haul communications.

We perform a systematic analysis of a system consisting of a two-stage Colpitts oscillator. This well-known chaotic oscillator is a modification of the standard Colpitts oscillator obtained by adding an extra transistor and a capacitor to the basic circuit. The two-stage Colpitts oscillator exhibits better spectral characteristics compared to a classical single-stage Colpitts oscillator. This interesting feature is suitable for chaos-based secure communication applications. We derive a smooth mathematical model (i.e., sets of nonlinear ordinary differential equations) to describe the dynamics of the system. The stability of the equilibrium states is carried out and conditions for the oc-J. Kengne ( ) · V.A. Fono Laboratoire d'Automatique et d'Informatique Appliquée currence of Hopf bifurcations are obtained. The numerical exploration reveals various bifurcation scenarios including period-doubling and interior crisis transitions to chaos. The connection between the system parameters and various dynamical regimes is established with particular emphasis on the role of both bias (i.e., power supply) and damping on the dynamics of the oscillator. Such an approach is particularly interesting as the results obtained are very useful for design engineers. The real physical implementation (i.e., use of electronic components) of the oscillator is considered to validate the theoretical analysis through several comparisons between experimental and numerical results.

This paper describes an experimental approach to determine the correlation between port scans and attacks. Discussions in the security community often state that port scans should be considered as precursors to an attack. However, very few studies have been conducted to quantify the validity of this hypothesis. In this paper, attack data were collected using a test-bed dedicated to monitoring attackers. The data collected consist of port scans, ICMP scans, vulnerability scans, successful attacks and management traffic. Two experiments were performed to validate the hypothesis of linking port scans and vulnerability scans to the number of packets observed per connection. Customized scripts were then developed to filter the collected data and group them on the basis of scans and attacks between a source and destination IP address pair. The correlation of the filtered data groups was assessed. The analyzed data consists of forty-eight days of data collection for two target computers on a heavily utilized subnet.

Visible Light Communication (VLC) is a blooming research area which uses visible light spectrum as the communication channel. Exponential growth of Light Emitting Diodes (LEDs) deployment as a light source is encouraged to use for communication purposes as well. With the introduction of VLC, LED can be used for communication while providing the primary function of illumination. Since location-based network access protocols have not been implemented for Wi-Fi devices, this research has been conducted with the intention of using VLC to perform location-based authentication. In our location authentication protocol, VLC technology is used for authentication purpose and Wi-Fi is used for data transfer once the device has been authenticated. The proposed protocol provides location-based connectivity to Wi-Fi devices with minimum changes to Remote Authentication Dial-In User Service (RADIUS) and Wi-Fi Protected Access 2 (WPA2) protocol by using VLC.

Abstruct-A circuit implementation of the chaotic Lorenz system is described. The chaotic behavior of the circuit closely matches the results predicted by numerical experiments. Using the concept of synchronized chaotic systems (SCS's), two possible approaches to secure communications are demonstrated with the Lorenz circuit implemented in both the transmitter and receiver. In the first approach, a chaotic masking signal is added at the transmitter to the message, and at the receiver, the masking is regenerated and subtracted from the received signal. The second approach utilizes modulation of the coefficients of the chaotic system in the transmitter and corresponding detection of synchronization error in the receiver to transmit binary-valued bit streams.