Chaos-based communication scheme using proportional and proportional-integral observers

In this paper, we propose a new chaos-based communication scheme using the observers. The novelty lies in the masking procedure that is employed to hide the confidential information using the chaotic oscillator. We use a combination of the addition and inclusion methods to mask the information. The performance of two observers, the proportional observer (P-observer) and the proportional integral observer (PI-observer) is compared that are employed as receivers for the proposed communication scheme. We show that the P-observer is not suitable scheme since it imposes unpractical constraints on the messages to be transmitted. On the other hand, we show that the PI-observer is the better solution because it allows greater flexibility in choosing the gains of the observer and does not impose any unpractical restrictions on the message

Design and Implementation of Secure Chaotic Communication Systems

Chaotic systems have properties such as ergodicity, sensitivity to initial conditions/parameter mismatches, mixing property, deterministic dynamics, structure complexity, to mention a few, that map nicely with cryptographic requirements such as confusion, diffusion, deterministic pseudorandomness, algorithm complexity. Furthermore, the possibility of chaotic synchronization, where the master system (transmitter) is driving the slave system (receiver) by its output signal, made it probable for the possible utilization of chaotic systems to implement security in the communication systems. Many methods like chaotic masking, chaotic modulation, inclusion, chaotic shift keying (CSK) had been proposed however, many attack methods later showed them to be insecure. Different modifications of these methods also exist in the literature to improve the security, but almost all suffer from the same drawback. Therefore, the implementation of chaotic systems in security still remains a challenge. In this work, different possibilities on how it might be possible to improve the security of the existing methods are explored. The main problem with the existing methods is that the message imprint could be found in the dynamics of the transmitted signal, therefore by some signal processing or pattern classification techniques, etc, allow the exposition of the hidden message. Therefore, the challenge is to remove any pattern or change in dynamics that the message might bring in the transmitted signal

Secure communication based on indirect coupled synchronization

In this paper, a secure communication system composed of four chaotic oscillators is proposed. Two of these oscillators are unidirectionally coupled and employed as transmitter and receiver. The other two oscillators are indirectly coupled and are employed as keystream generators. The novelty lies in the generation of the same chaotic keystream both in the transmitter and receiver side for encryption and decryption purposes. We show, in particular, that it is possible to synchronize the two keystream generators even though they are not directly coupled. So doing, an estimation of the keystream is obtained allowing decrypting the message. The main feature of the proposed communication scheme is that the keystream cannot be generated with the sole knowledge of the transmitted chaotic signal, hence making it very secure. The performance of the proposed communication scheme is shown via simulation using the Chua and Lorenz oscillators

Implementation of a secure digital chaotic communication scheme on a DSP board

In this paper, a new a secure communication scheme using chaotic signal for transmitting binary digital signals is proposed and which is then implemented on a Digital Signal Processor (DSP) board. The method uses the idea of indirect coupled synchronization for generating the same keystream in the transmitter and receiver side. This chaotic keystream is applied to encrypt the message signal before being modulated with a chaotic carrier generated from the transmitter. Discrete chaotic maps, 3D Henon map and Lorenz system are used as transmitter/receiver and key generators respectively. The overall system is experimentally implemented in the TMS320C6713 DSK board using code composer and Simulink showing the successful message extraction thus proving the feasibility of the system in the DSP board

EVALUATION OF ANTIOXIDANT POTENTIAL AND QUANTITATIVE ESTIMATION OF PHENOLIC AND FLAVONOID CONTENT IN SOME SELECTED NEPALESE MEDICINAL PLANTS

Objective: The aim of this study is to evaluate the antioxidant potential, determination of total phenolic and flavonoid content in nine selected medicinal plants Spondias pinnata, Melia azedarach, Ageratina adenophora, Urtica dioica, Curcuma longa, Bauhinia variegata, Elaeocarpus angustifolius Blume, Achyranthes aspera, and Psidium guajava from Kavre district of Nepal using in vitro studies. Methods: Methanolic plant extracts were prepared by cold percolation method. The methanol extract of nine medicinal plants collected from Kavre district of Nepal, was screened for assessing bioactive phytoconstituents followed by antioxidant property, total phenolic, and flavonoid content. Different plants collected were powdered and extracted with methanol, concentrated by a rotatory evaporator and analyzed for the presence of phytochemicals. The antioxidant potential of the plant extracts was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Results: The phytochemical analysis of methanolic extracts of all nine medicinal plants displayed the presence of various secondary metabolites such as alkaloids, flavonoids, polyphenols, saponins, and quinones. The extract of S. pinnata showed the highest percentage of radical scavenging activity up to 87.94±1.88 with 50% inhibitory concentration (IC50) 17.51±1.27 μg/mL, followed by B. variegata, 80.63±1.06 with IC50 value 26.55±2.61 μg/mL. The standard, ascorbic acid has IC50 value of 20.13±1.17 μg/mL. Further, the ethyl acetate fraction of S. pinnata showed the maximum percentage of radical scavenging (85.92±1.37) with IC50 value of 46.95±1.17 μg/mL. Moreover, S. pinnata displayed the highest total phenolic content (TPC) 48.26±1.23 mg GAE/g (milligram gallic acid equivalent per gram) extract while the highest flavonoid content was displayed by Melia azedarach 41.07±1.53 mg QE/g (milligram quercetin equivalent per gram) extract measured by the Folin–Ciocalteu reagent method and aluminum chloride colorimetric method. Conclusions: The preliminary results of this study have put forward the extract of S. pinnata showed the highest percentage of radical scavenging activity and S. pinnata displayed the highest TPC while the highest flavonoid content was displayed by Melia azedarach methanolic extracts although the further studies are needed to assess its mechanism of action

Smart street lighting over narrowband PLC in a smart city: The Triangulum case study

As municipalities continue to embrace digital revolution in a bid to become smarter cities, the unique intersection between ICT and development road map is inspiring new innovative applications. While this quest for smart city continues, the transformation of street lighting has become a topical issue. As part of ongoing investigation in Triangulum smart city project, this paper presents some simulation results on the use of narrowband powerline communication (NPLC) for street lights monitoring and control. The results show that, with low power, NPLC can support a 3.5km network of street lights without using a relay. It is also shown that, when the data packet size quadruples, latency degrades by up to 22.63% (242.03ms) in the worst case

A novel chaotic encryption technique for secure communication

Abstract: In this work, a novel chaotic encryption technique is proposed to realize a secure communication system. In the proposed method, the message signal to be transmitted is first encrypted using a chaotic keystream and then masked with a chaotic signal. At the receiver end, the received chaotic signal is used for synchronization and to recover the encrypted signal. After applying the same keystream used in transmitter side, the message signal could be decrypted back. The main contribution of this work is generation of the keystream which is not part of the transmitter chaotic oscillator but is produced using an oscillator of different structure

Design and implementation of secure chaotic communication systems

Chaotic systems have properties such as ergodicity, sensitivity to initial conditions/parameter mismatches, mixing property, deterministic dynamics, structure complexity, to mention a few, that map nicely with cryptographic requirements such as confusion, diffusion, deterministic pseudorandomness, algorithm complexity. Furthermore, the possibility of chaotic synchronization, where the master system (transmitter) is driving the slave system (receiver) by its output signal, made it probable for the possible utilization of chaotic systems to implement security in the communication systems. Many methods like chaotic masking, chaotic modulation, inclusion, chaotic shift keying (CSK) had been proposed however, many attack methods later showed them to be insecure. Different modifications of these methods also exist in the literature to improve the security, but almost all suffer from the same drawback. Therefore, the implementation of chaotic systems in security still remains a challenge. In this work, different possibilities on how it might be possible to improve the security of the existing methods are explored. The main problem with the existing methods is that the message imprint could be found in the dynamics of the transmitted signal, therefore by some signal processing or pattern classification techniques, etc, allow the exposition of the hidden message. Therefore, the challenge is to remove any pattern or change in dynamics that the message might bring in the transmitted signal.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Evolutionary Algorithms in Web Security: Exploring Untapped Potential

Many aspects of our lives are dependent upon the Web. Research that considers how we can better protect the Web and the products and services delivered using it-that is research into Web Security-is therefore of the upmost importance. Consequently, this paper considers evolutionary algorithms and their potential (which is to tap into and harness the power of natural evolution) within the field of Web Security. The paper provides a concise overview of existing studies that have used evolutionary algorithms as a tool within Web Security. More specifically, the paper considers the manner in which evolutionary algorithms have been applied, the types of problems that they have been applied to, and the way in which they have been assessed or evaluated. Furthermore, an opportunity to better harness the power of natural evolution within the field of Web Security, by applying modern evolutionary algorithms that draw inspiration from the open-ended aspect of natural evolution, is highlighted and discussed