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This paper introduces an audio encryption algorithm based on permutation of audio samples using discrete modified Henon map followed by substitution operation with keystream generated from the modified Lorenz-Hyperchaotic system. In this work, the audio file is initially compressed by Fast Walsh Hadamard Transform (FWHT) for removing the residual intelligibility in the transform domain. The resulting file is then encrypted in two phases. In the first phase permutation operation is carried out using modified discrete Henon map to weaken the correlation between adjacent samples. In the second phase it utilizes modified-Lorenz hyperchaotic system for substitution operation to fill the silent periods within the speech conversation. Dynamic keystream generation mechanism is also introduced to enhance the correlation between plaintext and encrypted text. Various quality metrics analysis such as correlation, signal to noise ratio (SNR), differential attacks, spectral entropy, histogram analysis, keyspace and key sensitivity are carried out to evaluate the quality of the proposed algorithm. The simulation results and numerical analyses demonstrate that the proposed algorithm has excellent security performance and robust against various cryptographic attacks. [ABSTRACT FROM AUTHOR]

The Henon map forms one of the most-studied two-dimensional discrete-time dynamical systems that exhibits chaotic behavior. The Henon map takes a point (Xn,Yn) in the plane andmaps it to a new point (Xn+1,Yn+1). In this paper, a chaotic pulse generator based on the chaotic Henon map is proposed. It consists of aHenon map function subcircuit to realize the Henon map and another subcircuit to perform the iterative operation. The Henon map subcircuit comprises operational amplifiers, multipliers, delay elements and resistors, whereas, the iterative subcircuit is implemented with a simple design that comprises of an edge forming circuit followed by a monostable multivibrator and a voltage controlled switch without the use of any clock control. The proposed design can be used to realize the Henon map and also to generate a chaotic pulse train, with a controllable time interval and pulse position. The proposed circuit is implemented and simulated using Multisim 13.0 and MATLAB R2019b. The chaotic nature of the generated pulse train and also the time interval between the consecutive pulses is verified by the calculation of its Lyapunov exponents. [ABSTRACT FROM AUTHOR]

Trust between partners, a key element enabling coordination across supply chains, has recently started gaining attention in humanitarian operations literature. Yet, empirical examination of this concept is scant. Borrowing from extant literature on trust within organisational behaviour stream, this paper aims to empirically verify trust formation types: companion, competence and commitment, in a disaster relief supply chain using primary and secondary data from an Indian Humanitarian relief organisation (HRO). Further, we identify variations in trust formation during disaster relief activities and developmental programmes, and between upstream and downstream partners of a humanitarian relief organisation. Based on the results of our content analysis, we contend that while companion based trust is significantly more prevalent during developmental programmes, competence based trust is important during both disaster periods and otherwise. We also find that there are significant differences in the trust formation between upstream and downstream partners and the HRO. This study has significant theoretical and practical implications on identifying the role of trust in humanitarian operations. [ABSTRACT FROM AUTHOR]