Statistical Test Suite Research Articles

Design of pseudo-random number generator from turbulence padded chaotic map

Transmission of the information in any form requires security. Security protocols used for communication rely on the use of random numbers. Pseudo-random numbers are required with good statistical properties and efficiency. The use of a single chaotic map may not produce enough randomness. The turbulence is padded into the existing map to improve its chaotic behaviour and increase the periodicity. A Pseudo-random number generator (PRNG) with this architecture is devised to generate random bit sequences from secret keys. The statistical properties of newly constructed PRNG are tested with NIST SP 800–22 statistical test suite and were shown to have good randomness. To ensure its usability in cryptographic applications, we analysed the size of its key space, key sensitivity, and performance speed. The test results show that the newly designed PRNG has a 3.6% increase in key space and a 5% increase in its performance speed compared to existing chaotic PRNGs. The novel PRNG with faster performance is found suitable for lightweight cryptographic applications.

Demonstration of Three True Random Number Generator Circuits Using Memristor Created Entropy and Commercial Off-the-Shelf Components.

In this work, we build and test three memristor-based true random number generator (TRNG) circuits: two previously presented in the literature and one which is our own design. The functionality of each circuit is assessed using the National Institute of Standards and Technology (NIST) Statistical Test Suite (STS). The TRNG circuits were built using commercially available off-the-shelf parts, including the memristor. The results of this work confirm the usefulness of memristors for successful implementation of TRNG circuits, as well as the ease with which a TRNG can be built using simple circuit designs and off-the-shelf breadboard circuit components.

SECURITY ANALYSIS BETWEEN STATIC AND DYNAMIC S-BOXES IN BLOCK CIPHERS

The development of block ciphers has resulted in a number of cryptographic algorithms such as AES, aria, blowfish256, desl, and 3d-aes. AES is one of the best cryptographic algorithms that can be used to protect electronic data. However, the principal weakness in AES is the linearity in the s-box. The objective of this research is to investigate and evaluate the existing work related to the dynamic s-box. Other than that, the aim of this research is to design a dynamic s-box using affine transformation in order to increase the security of the encryption. The method to design is using java with the NetBeans software. The proposed block cipher will be tested using NIST statistical test suite to test the randomness of the algorithm. Besides, the strength of the s-box will be analyzed using the s-box evaluation tool (set). The cryptographic strength depends strongly on the choice of s-box. Therefore, this new proposed block cipher can be used by countries, organizations, stakeholders, or interested parties as one of the secure algorithms to increase the protection of the information and also will contribute as an alternative to other cryptographic algorithms in computer security research.

Pseudo-random number generator based on a generalized conservative Sprott-A system

Pseudo-random number generator (PRNG) has been widely used in digital image encryption and secure communication. This paper reports a novel PRNG based on a generalized Sprott-A system that is conservative. To validate whether the system can produce high quality chaotic signals, we numerically investigate its conservative chaotic dynamics and the complexity based on the approximate entropy algorithm. In this PRNG, we first select an initial value as a key to generate conservative chaotic sequence, then a scrambling operation is introduced into the process to enhance the complexity of the sequence, which is quantified by the binary quantization method. The national institute of standards and technology statistical test suite is used to test the randomness of the scrambled sequence, and we also analyze its correlation, keyspace, key sensitivity, linear complexity, information entropy and histogram. The numerical results show that the binary random sequence produced by the PRNG algorithm has the advantages of the large keyspace, high sensitivity, and good randomness. Moreover, an improved finite precision period calculation (FPPC) algorithm is proposed to calculate the repetition rate of the sequence and further discuss the relationship between the repetition rate and fixed-point accuracy; the proposed FPPC algorithm can be used to set the fixed-point notation for the proposed PRNG and avoid the degradation of the chaotic system due to the data precision.

Generation of an EDS Key Based on a Graphic Image of a Subject’s Face Using the RC4 Algorithm

Modern facial recognition algorithms make it possible to identify system users by their appearance with a high level of accuracy. In such cases, an image of the user’s face is converted to parameters that later are used in a recognition process. On the other hand, the obtained parameters can be used as data for pseudo-random number generators. However, the closeness of the sequence generated by such a generator to a truly random one is questionable. This paper proposes a system which is able to authenticate users by their face, and generate pseudo-random values based on the facial image that will later serve to generate an encryption key. The generator of a random value was tested with the NIST Statistical Test Suite. The subsystem of image recognition was also tested under various conditions of taking the image. The test results of the random value generator show a satisfactory level of randomness, i.e., an average of 0.47 random generation (NIST test), with 95% accuracy of the system as a whole.

DS2B: Dynamic and Secure Substitution Box for Efficient Speech Encryption Engine

This paper proposes an efficient encryption technique based on Dynamic and Secure Substitution Box (DS2B) design suitable for IoT and resource-constrained platforms. The DS2B has the advantages of simple structure and good encryption performance. A different number of strong S-boxes could be generated with minor variations in the DS2B parameters. Performance analyses of the DS2B, including differential/linear cryptanalysis, bijective, nonlinearity, strict avalanche criterion (SAC), and bit independence criterion (BIC) have been presented where high nonlinearity, and low differential uniformity are achieved. Besides, a comparison with recent S-boxes is introduced which shows the robustness of the DS2B. To verify the DS2B, a speech encryption engine was realized on FPGA. Various security analyses were evaluated including the National Institute of Standards & Technology (NIST) statistical test suite, number of samples changes rate NSCR, mean square error (MSE), correlation, histogram, and spectrogram. In this work, the silence periods are encrypted in a way that makes them much harder to detect using the DS2B. The proposed encryption scheme achieved a throughput of 9.87 G bit/s, which is higher than previous work. A Xilinx Nexys 4 FPGA evaluation board was used for implementing and verifying the design.

A Polymorphic Advanced Encryption Standard – A Novel Approach

To secure various forms of data, a polymorphic variant of the Advanced Encryption Standard (P-AES) has been introduced. In the P-AES, the AES parameters' values will change with every new key. The exact values will be available only to legitimate communicating parties during execution time. To achieve these objectives, the basic AES transformations, SubBytes, ShiftRows, and MixColumns, have been made key-dependent in the proposed P-AES. Hence, with every new key, these transformations will operate differently. The receiver can retrieve the operations' details from the encryption key. Consequently, polymorphism has been achieved and interoperability remains intact. P-AES has been implemented seamlessly using the existing AES modules, and the performance was more or less equal to the AES performance (71 and 70 milliseconds to encrypt 500 bytes using the P-AES and the AES respectively). From a security standpoint, the proposed P-AES fully complies with Kerckhoff's principle. This means the cipher has an open design, and the security provided by the P-AES depends only on the secrecy of the encryption key. The cipher resistance to differential and linear attacks has been proved. Moreover, the resulting proposed cipher can operate in 128 different ways, which will significantly reduce the capabilities of any sophisticated attacker. Furthermore, the proposed P-AES's scores of the key avalanche and the plaintext avalanche were 0.496 and 0.504 respectively. Finally, the Statistical Test Suite (STS) recommended by the NIST has been used to ensure the randomness of the cipher output, and the cipher has passed all the STS tests.

O2MD²: A New Post-Quantum Cryptosystem With One-to-Many Distributed Key Management Based on Prime Modulo Double Encapsulation

Polynomial-time attacks designed to run on quantum computers and capable of breaking RSA and AES are already known. It is imperative to develop quantum-resistant algorithms before quantum computers become available. Computationally hard problems defined on lattices have been proposed as the fundamental security bases for a new type of cryptography. The National Institute of Standards and Technology (NIST) recently hosted the Post-Quantum Cryptography Standardization project, aiming to create a roster of innovative post-quantum cryptosystems. These candidates have been publicly available for testing since early 2017. As they are currently under analysis, new proposals are still desirable. As such, we use the ring learning with errors (RLWE) problem combined with arithmetic functions to propose the O2MD <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> cryptosystem, which provides a one-to-many private/public key architecture having a distributed key refresh for a network of users while working on multiple polynomial rings over different prime order fields. Our solution has three different frameworks that reach AES-256 equivalent security, and provides message integrity and message authenticity verifications. We compare our solution's speed against the speed of the twenty-six different implementations from seven popular candidates in the NIST project, and our cryptosystem performs from 2 to 4 orders of magnitude faster than them. We also propose six different implementations that reach the security levels 1, 3 and 5 proposed in the NIST competition. Finally, we used the NIST Statistical Test Suite to verify the indistinguishability of our produced ciphertexts against randomly generated noise.

Publicly verifiable threshold secret sharing based onthree‐dimensional‐cellularautomata

AbstractSecret sharing schemes are being widely used to distribute a secret between various participants so that an authorized subset of participants belonging to appropriate access structures can reconstruct this secret. However, a dealer might get corrupted by adversaries and may influence this secret sharing or the reconstruction process. Verifiable secret sharing (VSS) overcomes this issue by adding a verifiability protocol to the original secret sharing scheme. This article proposes a computationally secure publicly verifiable secret sharing scheme based on the three‐dimensional cellular automata (3D‐CA). Unlike the more widely used linear secret sharing schemes or secret sharing scheme based on the Chinese remainder theorem, our proposed scheme performs the secret sharing using 3D‐CA. The secret is considered one of the initial configurations of the 3D‐CA, and the following configurations are devised to be the shares distributed among the participants. Update mechanisms and various rules make it hard for an adversary to corrupt or duplicate a share. To make it even more efficient, we have added a verifiability layer such that a dealer posts a public share and private share to each shareholder. The verifiability layer reduces the interaction between dealer and participants and hence increases the security. The randomness of the shares has been calculated using the National Institute of Standards and Technology statistical test suite.

A 0.7 pJ/bit, 1.5 Gbps Energy-Efficient Image-Based True Random Number Generator

ABSTRACT Random numbers cover a vast spectrum of applications. Hence generating it effectively with high performance is the need of the hour. This paper presents the novel design and implementation of high performance and energy-efficient true random number generator (TRNG) using images as a source. In the proposed work, the harvesting mechanism that comprises of hashing technique block (HTB) is used to reduce the intensity of pattern, an event counting circuit (ECC) is used for comparing the events, while a linear feedback shift register (LFSR), designed by considering a primitive polynomial function, is used to obtain the random numbers. The addition of 8 × 1 multiplexer (MUX) with meta-stable circuit feeder control lines had further increased the unpredictability in the proposed system. The implementation of the work has been done in the Xilinx Vivado simulation tool followed by the Cadence Virtuoso circuit simulation environment. The maximum speed of 1.5 Gbps with power dissipation of 1 mW and 0.7 pJ/bit energy efficiency with a layout area of 2218 μm2 has been achieved in this work. NIST 800.22 statistical test suite and uniformity test comprising of Kolmogorov–Smirnov and Chi-square test have also been performed for validation of generated random numbers. The obtained binary sequences have passed all tests successfully with calculated entropy up to 0.999999999. The autocorrelation factor (ACF) of the output bit streams has been obtained as approximately zero (∼0) within 96% confidence bounds of a Gaussian distribution (µ = 0, 3σ). The proposed design is thus suitable for true random number generation.

On pseudorandom number generators

&lt;p class="Abstract"&gt;Statistical sampling and simulations produced by algorithms require fast random number generators; however, true random number generators are often too slow for the purpose, so pseudorandom number generators are usually more suitable. But choosing and using a pseudorandom number generator is no simple task; most pseudorandom number generators fail statistical tests. Default pseudorandom number generators offered by programming languages usually do not offer sufficient statistical properties. Testing random number generators so as to choose one for a project is essential to know its limitations and decide whether the choice fits the project’s objectives. However, this study presents a reproducible experiment that demonstrates that, despite all the contributions it made when it was first published, the popular NIST SP 800-22 statistical test suite as implemented in the software package is inadequate for testing generators.&lt;/p&gt;

Atmospheric pressure air microplasma current time series for true random bit generation

Generating true random bits of high quality at high data rates is usually viewed as a challenging task. To do so, physical sources of entropy with wide bandwidth are required which are able to provide truly random bits and not pseudorandom bits, as it is the case with deterministic algorithms and chaotic systems. In this work we demonstrate a reliable high-speed true random bit generator (TRBG) device based on the unpredictable electrical current time series of atmospheric pressure air microplasma (APAMP). After binarization of the sampled current time series, no further post-processing was needed in order for the bitstreams to pass all 15 tests of the NIST SP 800-22 statistical test suite. Several configurations of the system have been successfully tested at different sampling rates up to 100 MS/s, and with different inter-electrode distances giving visible/non-visible optical emissions. The cost-effectiveness, simplicity and ease of implementation of the proposed APAMP system compared to others makes it a very promising solution for portable TRBGs.

DNA synthesis for true random number generation

The volume of securely encrypted data transmission required by today’s network complexity of people, transactions and interactions increases continuously. To guarantee security of encryption and decryption schemes for exchanging sensitive information, large volumes of true random numbers are required. Here we present a method to exploit the stochastic nature of chemistry by synthesizing DNA strands composed of random nucleotides. We compare three commercial random DNA syntheses giving a measure for robustness and synthesis distribution of nucleotides and show that using DNA for random number generation, we can obtain 7 million GB of randomness from one synthesis run, which can be read out using state-of-the-art sequencing technologies at rates of ca. 300 kB/s. Using the von Neumann algorithm for data compression, we remove bias introduced from human or technological sources and assess randomness using NIST’s statistical test suite.

Randomness Analysis on Lightweight Block Cipher, PRESENT

Lightweight cryptography is an area of current research conducted by academicians and cryptographic experts to ensure the security of data in limited-resource devices such as RFID tags, medical and health care devices and sensor networks. One of the lightweight algorithms built is the PRESENT algorithm. To this day, PRESENT has been a reference for lightweight block cipher algorithms and is incorporated into Lightweight Cryptography Standard ISO/IEC 29192-2. The capacity to act as a random number generator is one of the key requirements when designing an algorithm. Thus, this study aims to examine the capabilities of the PRESENT algorithm as a random number generator. By using the NIST Statistical Test Suite, a randomness analysis is performed on the PRESENT algorithm. A total of six data categories i.e., Strict Key Avalanche, Strict Plaintext Avalanche, High-Density Key, Low- Density Key, Low-Density Plaintext and High-Density Plaintext were applied to generate 100 input sequences for each algorithm. From the analysis, the outputs generated from the PRESENT algorithm are essentially non-random based on the 1% significance level.

Discover novel disease-associated genes based on regulatory networks of long-range chromatin interactions.

Identifying genes and non-coding genetic variants that are genetically associated with complex diseases and the underlying mechanisms is one of the most important questions in functional genomics. Due to the limited statistical power and the lack of mechanistic modeling, traditional genome-wide association studies (GWAS) is restricted to fully address this question. Based on multi-omics data integration, cell-type specific regulatory networks can be built to improve GWAS analysis. In this study, we developed a new computational infrastructure, APRIL, to incorporate 3D chromatin interactions into regulatory network construction, which can extend the networks to include long-range cis-regulatory links between non-coding GWAS SNPs and target genes. Combinatorial transcription factors that co-regulate groups of genes are also inferred to further expand the networks with trans-regulation. A suite of machine learning predictions and statistical tests are incorporated in APRIL to predict novel disease-associated genes based on the expanded regulatory networks. Important features of non-coding regulatory elements and genetic variants are prioritized in network-based predictions, providing systems-level insights on the mechanisms of transcriptional dysregulation associated with complex diseases.

A switched chaotic encryption scheme using multi-mode generalized modified transition map

This paper presents a multi-mode generalized modified transition chaotic map and a switched chaotic encryption scheme based on it. Eight different modes of operation can be selected based on the map graph (concave or convex), the range modification procedure (shrinking or widening) and the sign of one of its independent parameters. The generalization and modification preserve the controllability and continuous chaotic behavior properties, respectively. For the same encryption key and map equation, multi-mode operation occurs through switching between four alternatives of the dependent parameters. Switching between various modes is shown to overpass single modes in randomness by investigating the frequency distribution, autocorrelation function, histograms and 0-1 test. In addition, most bits, 75%, of the scaled and quantized chaotic output are shown to be suitable for pseudo-random number generation based on National Institute of Standards & Technology (NIST) statistical test suite. The performance of the proposed scheme is validated for several speech, grayscale and RGB images through various evaluation criteria, where good results are achieved. These criteria include basic perceptual and statistical aspects, the more advanced NIST tests, key sensitivity and robustness against brute force and differential attacks. The efficiency of the scheme is improved by up to three or six times faster than encrypting one sample or one channel of a pixel at a time for speech and image inputs, respectively. The proposed scheme demonstrates good security and efficiency with more applied evaluation criteria compared to similar recent works.

0.4 mW, 0.27 pJ/bit true random number generator using jitter, metastability and current starved topology

This study introduces the design of true random number generator (TRNG) using jitter, metastability and current starved topology. The proposed design consisted of a current starved inverter-based ring oscillator (RO) with a high-frequency divider block (designed by T-FF followed by D-FF to address setup and hold time issues), jitter extraction and metastable block followed by two sampling blocks. The design avails fewer amenities to yield the reduction in hardware and enhances the degree of randomness. The post-layout simulation of the proposed work was performed using a 180 nm CMOS technology environment in the Cadence Virtuoso tool. The speed and power dissipation achieved are 1.5 Gbps and 0.4 mW, respectively, with an efficiency of 0.27 pJ/bit. The effect of temperature and variation in supply voltages (by 10% around its nominal value) is also investigated on the generated random numbers through parametric analysis. For validation of randomness, the generated random signals are first sampled and then converted in binary format using MATLAB and finally verified by Kolmogorov–Smirnov and Chi-square test for the uniformity and independency. The validity of the proposed work is done by NIST 800.22 statistical test suite. The proposed TRNG design achieved a very high-pass efficiency.

IEVCA: An efficient image encryption technique for IoT applications using 2-D Von-Neumann cellular automata

Present era is marked by exponential growth in transfer of multimedia data through internet. Most of the Internet-of-Things(IoT) applications send images to cloud storages through internet. However, in sensitive applications such as healthcare, defense, etc., these images should be encrypted before transmission through insecure public channels to gateway fog nodes. Conventional encryption algorithms cannot be used there due to the resource constraint characters of IoT devices. Here, Cellular Automata (CA) based encryption algorithms can be used because of their inherent simplicity in implementation in hardware, without affecting the capability of generating highly random sequences. In this paper, a lightweight, robust and secure image encryption technique has been proposed using 2-D Von-Neumann Cellular Automata (VCA), called IEVCA, which is lossless, correlation immune and has all the essential properties of a good image cipher. Additionally, the proposed technique passes all the randomness tests of DIEHARD and NIST statistical test suites. Moreover, several security and performance analyses of the IEVCA proved its efficiency and resistance against security attacks. Experimental results of the IEVCA show its better performance when compared to the existing encryption techniques.

An unforced megastable chaotic oscillator and its application on protecting electrophysiological signals

Abstract In this paper, we introduce a novel 3D chaotic oscillator which shows megastability without any external excitation. Some important dynamical properties of the proposed novel system were derived and investigated. Data protection application and its security analysis were realized for electrophysiological signals such as ECG, EEG and EMG on a microcomputer. This paper includes both encryption and data hiding processes for high security. Also a user interface was developed. For the encryption process, random numbers were generated by the megastable chaotic oscillator. These random numbers were tested with NIST-800-22 test which is the most widely accepted statistical test suite. The encrypted electrophysiological signals were analyzed by entropy, differential attacks, histogram, correlation, initial condition sensitivity, etc. The results of the analysis have shown that the proposed two level security method can be used in many fields as mobile. The most important feature of this paper is that both encryption and data hiding processes were implemented for electrophysiological signals. The experimental results verify that the proposed method has high security and is suitable for the protection of vital electrophysiological signals.

Holographically controlled random numbers from entangled twisted photons

We present a quantum random number generator (QRNG) based on the random outcomes inherent in projective measurements on a superposition of quantum states of light. Firstly, we use multiplexed holograms encoded on a spatial light modulator to spatially map down-converted photons onto a superposition of optical paths. This gives us full digital control of the mapping process which we can tailor to achieve any desired probability distribution. More importantly, we use this method to account for any bias present within our transmission and detection system, forgoing the need for time-consuming and inefficient unbiasing algorithms. Our QRNG achieved a min-entropy of $\text{H}_{\text{min}}=0.9991\pm0.0003$ bits per photon and passed the NIST statistical test suite. Furthermore, we extend our approach to realise a QRNG based on photons entangled in their orbital angular momentum (OAM) degree of freedom. This combination of digital holograms and projective measurements on arbitrary OAM combinations allowed us to generate random numbers with arbitrary distributions, in effect tailoring the system's entropy while maintaining the inherent quantum irreproducibility. Such techniques allow access to the higher-dimensional OAM Hilbert space, opening up an avenue for generating multiple random bits per photon.