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The advancement in cryptographic algorithms is the primary need for modern secure communication systems. In secure communication system, the stream cipher serves the basis for cryptographic algorithms. The properties of cryptographic algorithms are often analyzed on the basis of randomness involved in implementing cipher texts while complexity of the hardware is also taken care of. Therefore, the main objective of this paper is to propose a new stream cipher scheme having higher complexity (high degree of randomness) while keeping the hardware as simple as possible. The proposed stream cipher algorithm gives the new direction to develop the highly secure and simple models in communication field. The proposed scheme offers the benefit of adjusting variable-length key(s) according to the variable length of plaintext using modular arithmetic and memristor—based chaotic behavioral Chua's circuit. To explain the encryption–decryption process at transmitter and receiver ends, the Devanagari script has been taken. Although, any other script or data type is supported by the proposed algorithm. In addition, the synchronization is also achieved without having any requirement of additional process. [ABSTRACT FROM AUTHOR]

In transmit-reference (TR) receivers, noise in the reference (pilot) pulse causes a noise × noise term in the decision statistic. This term severely degrades receiver performance. We propose a detection algorithm to decrease the noise in the reference pulse in TR receivers. Computer simulations show that at BER = 10−5, the proposed algorithm outperforms the existing algorithm by about 0.8 dB in both coded and uncoded scenarios. In high-rate applications, inter-symbol interference (ISI) drastically impairs the received signal. Monobit quantization intensifies the ISI and hence dramatically degrades the receiver performance. At first glance, channel coding increases ISI and seems useless to combat ISI. However, we propose to employ channel coding to overcome the severe performance loss caused by ISI. Simulation results show that in high SNR values, channel coding tackles the ISI problem especially when convolutional coding is used. Moreover, simulations reveal that convolutional coding is more robust to ISI compared to block coding schemes. Furthermore, the digital circuit design of coded/uncoded traditional and proposed monobit TR receivers is done in 0.18 µm CMOS technology at 2 V supply voltage. Simulations confirm the numerical results obtained in MATLAB. Finally, the power consumption of each receiver is reported. [ABSTRACT FROM AUTHOR]