This paper presents an analytical study on the use of deterministic chaos as an entropy source for the generation of random numbers. The chaotic signal generated by a phase-locked loop (PLL) device is investigated using numerical simulations. Depending on the system parameters, the chaos originating from the PLL device can be either bounded or unbounded in the phase direction. Bounded and unbounded chaos differs in terms of the flatness of the power spectrum associated with the chaotic signal. Random bits are generated by regular sampling of the signal from bounded and unbounded chaos. A white Gaussian noise source is also sampled regularly to generate random bits. By varying the sampling frequency, and based on the autocorrelation and the approximate entropy analysis of the resulting bit sequences, a comparison is made between bounded chaos, unbounded chaos and Gaussian white noise as an entropy source for random number generators.

This paper presents a random number generator (RNG) based on irregular sampling of regular waveform method where the irregular signal is obtained by combining Fibonacci-Galois ring oscillators with an XOR gate. The RNG is implemented on a FPGA (field-programmable gate array). The regular waveform generated by the digital clock manager of the FPGA, is sampled at times corresponding to certain number of rising edges of the irregular signal, and the resulting bit stream is subjected to statistical tests of randomness. It is demonstrated that the resulting bit sequence from the proposed RNG satisfies NIST 800-22 test suit and Rabbit and SmallCrush batteries from TestU01 library without any need for post-processing such as Von Neumann or XOR. A comparison between the methods regular sampling of irregular waveform and irregular sampling of regular waveform is given in terms of robustness against external interference. The impact of selection of Fibonacci-Galois polynomials is discussed. Using digital design flow for TSMC 65nm process, an asic implementation of the proposed RNG is given having 1115 gates and 4.811 mW estimated power.

Robotic systems are widely used in industry, agriculture, the inspection of infrastructure, and even in our daily lives. The safety and security of robotic systems have become a primary concern as their interaction with humans increases. In this context, attacks on robotic systems have increased for diversified field applications. It is necessary to accurately detect these abnormal events in these systems as soon as possible. However, these systems also need a runtime verification approach on whether they conform to the established specifications. In this study, runtime verification for anomaly detection methods is proposed for the security of the robot operating system (ROS). Firstly, an anomaly detection method is proposed to detect unexpected situations, such as the number of the received packages being decreased under DoS attacks. Then, a holistic runtime verification architecture is proposed for the anomaly detection method. This architecture consists of three major entities: a verification device, an attacker device, and a robotic platform without losing generality. In the verification device, ROSMonitoring and Oracle are used to implement runtime verification. The proposed architecture is verified through an experimental setup. It is shown that the architecture can be used for runtime verification of different anomaly detection algorithms. A discussion on the security of robotic systems is also presented.

Metaverse was recently introduced as an online virtual world or world of worlds that incorporates the augmented/virtual/mixed/extended reality (AR/VR/MR/XR), Internet of Things (IoT), personalization with virtual avatars, interaction and communication interlinking real and/or virtual “things” with “things”. Metaverse users are supposed to live in a digital realm in which such living universes are created either as imaginative or realistic environments. This brings a new creative space for architects in the Architecture-Engineering-Construction (AEC) sector to design new buildings and cities in a semi-realistic digital world as they can be inspired by actual urban settings and augment these real or realistic environments towards a cyber environment. This paper aims to present such a cyber environment, called BIMyVerse, that blends IoT-enabled situational awareness, VR-supported integrated semantic digital twin models incorporating Building Information Model (BIM), Geographical Information System (GIS) and sensory cyberspace and explainable interpretations for better interaction with buildings and urban contexts. The proof of concept studies demonstrate how BIMyVerse can be used for i) situational fire regulation check and monitoring the maintenance status (building-scale); ii) circular economy provisioning through the digital twin of an urban transformation area (urban-scale).

This study presents the algebraic cryptanalysis of a continuous‐time chaotic random number generator (RNG) based on a Zhongtang chaotic system. The chaos‐based RNG provides key values for logic encryption, round key formation and the substitution box (S‐box) generation steps in AES (advanced encryption standard). In this study, an attack method is proposed to exploit the weaknesses of the chaos‐based RNG used in this cryptographic system. By observing a chaotic state variable and knowing the structure of the target RNG, output bit sequence of the target RNG is reproduced by a clone RNG used in master–slave synchronisation scheme. The feasibility of the attack system is confirmed through simulation and numerical results. Through this attack method, the same S‐box parameters and key values can be obtained which can be used for decryption of the proposed encryption algorithm. This study targets a specific continuous‐time chaos‐based RNG and the associated cryptographic system as a case study. However, the cryptanalysis method described in this study is applicable to any continuous‐time or discrete‐time chaos‐based RNGs. Therefore, this study highlights the security vulnerabilities of chaos‐based RNGs and emphasises that deterministic chaos phenomena itself should not be considered as the actual source of randomness.

A low-cost random number generator (RNG) based on a tetrahedral ring oscillator, which can be utilized in cryptographic systems, is presented. The proposed design exploits two metastable events in the oscillator caused by turning on and off three additional inverters in the classical tetrahedral oscillator, which improves entropy. The design is implemented on FPGA as a proof of concept, but the ASIC implementation will be carried out in the future. A method has been devised to implement this circuit on FPGA. Techniques to increase randomness have been used, such as adjusting the sampling signal considering 1 and 0 balance of the output. The proposed design is compared with the classical tetrahedral oscillator based RNG, and it is observed to be better. The RNG is tested with the National Institute of Standard and Technology (NIST) test suite to prove randomness. The design occupies an area of 0.0036mm2 with a power consumption of 200mW and a bit rate of 10Mb/s. The number of oscillators has been dropped by 60% compared to the classical method.