Statistical Test Suite Research Articles

A Novel Forgery Detection Mechanism for Sensitive Data

There are some applications of military and e-commerce networks, where security of transmitted data on unfriendly environment requires more concern as compared to other design issues like power and energy consumption. Data alterations in above mentioned applications can lead to irreparable losses; so to avoid such losses, we have to maintain Data Integrity in the communication network. This paper presents a novel and reliable Hash algorithm which inherits the basic architecture of SHA-1. Performance of proposed technique is compared with existing techniques through statistical test suite for random numbers. Results reveal that the suggested technique is more effective in terms of randomness than the existing algorithms. The proposed technique, thus, finds its applicability in the sensitive data environment.

Optimization of the Security-Performance Tradeoff in RC4 Encryption Algorithm

In this paper, we have investigated different vulnerabilities in RC4 and its enhanced variants to overcome the security attacks. It is established that in spite of several proposals, RC4 is not secure enough and a trade-off is always sought between security and network performance for overall provisioning of the secure communication. The main goal of the work presented in this paper is the optimization of security-performance tradeoff. We have proposed three RC4 variants referred to as RC4-M1, RC4-M2 and RC4-M3. Security of the proposed schemes is analyzed in terms of randomness and computational complexity. All the proposed variants qualify the NIST statistical test suite of randomness satisfactorily. The proposed schemes also offer computational complexity in terms of greater number of operations relative to the existing variants. The strength of the proposed schemes has been analyzed against different cryptanalytic attempts and shown the resistance of proposed schemes against attacks. The security-performance tradeoff has been analyzed in terms of run time, CPU cycles consumed, energy cost, and throughput. Encryption time of the proposed schemes--RC4-M1, RC4-M2 and RC4-M3 is 30.1, 10 and 48.7 % less as compared to RC4+ respectively. The results clearly indicate that the computation load of the proposed variants is significantly reduced as compared to the RC4+, concluding that the proposed schemes are computationally efficient. Our results and their analysis also recognize the suitability of the security algorithms for particular application areas.

Genipe: an automated genome-wide imputation pipeline with automatic reporting and statistical tools.

Summary: Genotype imputation is now commonly performed following genome-wide genotyping experiments. Imputation increases the density of analyzed genotypes in the dataset, enabling fine-mapping across the genome. However, the process of imputation using the most recent publicly available reference datasets can require considerable computation power and the management of hundreds of large intermediate files. We have developed genipe, a complete genome-wide imputation pipeline which includes automatic reporting, imputed data indexing and management, and a suite of statistical tests for imputed data commonly used in genetic epidemiology (Sequence Kernel Association Test, Cox proportional hazards for survival analysis, and linear mixed models for repeated measurements in longitudinal studies).Availability and Implementation: The genipe package is an open source Python software and is freely available for non-commercial use (CC BY-NC 4.0) at https://github.com/pgxcentre/genipe. Documentation and tutorials are available at http://pgxcentre.github.io/genipe.Contact: louis-philippe.lemieux.perreault@statgen.org or marie-pierre.dube@statgen.orgSupplementary information: Supplementary data are available at Bioinformatics online.

Brownian motion properties of optoelectronic random bit generators based on laser chaos.

The nondeterministic property of the optoelectronic random bit generator (RBG) based on laser chaos are experimentally analyzed from two aspects of the central limit theorem and law of iterated logarithm. The random bits are extracted from an optical feedback chaotic laser diode using a multi-bit extraction technique in the electrical domain. Our experimental results demonstrate that the generated random bits have no statistical distance from the Brownian motion, besides that they can pass the state-of-the-art industry-benchmark statistical test suite (NIST SP800-22). All of them give a mathematically provable evidence that the ultrafast random bit generator based on laser chaos can be used as a nondeterministic random bit source.

Design of a Chaotic Random Bit Generator Using a Duffing - van der Pol System

In this paper a chaotic random bit generator, which is based in one of the most well-known non-autonomous chaotic dynamical systems, the Duffing van der Pol, is presented. The basic component of this design approach is the use of the Poincaré map of the aforementioned system. The produced chaotic attractor of the Duffing van der Pol system is converted with the proposed method to a random bit sequence. Furthermore, for, improving the “randomness” of the produced bit streams the X-OR function in the outputs of two threshold circuits that use two variables x which are produced by the two Duffing – van der Pol's Poincaré maps is used. Finally, the produced bit sequence is subjected to the de-skewing technique to extract unbiased bits with no correlation and so to increase their complexity, as it is confirmed by the statistical test suite, FIPS-140-2.

More Reliable Approach for Detecting Data Alterations in Communication Networks

Security of precious data is the most critical design parameter of a communication network. Applications like online banking and military information exchange requires more concern over security regardless of other design issues like power and energy consumption. Data alterations in some applications can lead to severe irreparable losses. This paper presents a novel and reliable Hash algorithm which inherits the basic architecture of MD5. Performance of proposed technique is compared with existing MD5, SHA-160, SHA-256 and SHA-384 techniques through statistical test suite for random numbers. Results reveal that the suggested technique is more effective in terms of randomness than the MD5, SHA-160, SHA-256 and SHA-384. The proposed technique thus finds its applicability in the sensitive data environment.

Bias-free true random number generation using superconducting nanowire single-photon detectors

We demonstrate a bias-free true random number generator (TRNG) based on single photon detection using superconducting nanowire single photon detectors (SNSPDs). By comparing the photon detection signals of two consecutive laser pulses and extracting the random bits by the von Neumann correction method, we achieved a random number generation efficiency of 25% (a generation rate of 3.75 Mbit s−1 at a system clock rate of 15 MHz). Using a multi-channel superconducting nanowire single photon detector system with controllable pulse signal amplitudes, we detected the single photons with photon number resolution and positional sensitivity, which could further increase the random number generation efficiency. In a three-channel SNSPD system, the random number bit generation efficiency was improved to 75%, corresponding to a generation rate of 7.5 Mbit s−1 with a 10 MHz system clock rate. All of the generated random numbers successfully passed the statistical test suite.

Post-processing Free Quantum Random Number Generator Based on Avalanche Photodiode Array**Supported by the Chinese Academy of Sciences Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, Shanghai Branch, University of Science and Technology of China, and the National Natural Science Foundation of China under Grant No 11405172.

Quantum random number generators adopting single photon detection have been restricted due to the non-negligible dead time of avalanche photodiodes (APDs). We propose a new approach based on an APD array to improve the generation rate of random numbers significantly. This method compares the detectors' responses to consecutive optical pulses and generates the random sequence. We implement a demonstration experiment to show its simplicity, compactness and scalability. The generated numbers are proved to be unbiased, post-processing free, ready to use, and their randomness is verified by using the national institute of standard technology statistical test suite. The random bit generation efficiency is as high as 32.8% and the potential generation rate adopting the 32 × 32 APD array is up to tens of Gbits/s.

Corrected runs distribution test for pseudorandom number generators

Runs distribution test is an important statistical test based on Golomb's randomness postulates. It is an important randomness test included in some famous evaluation standards and statistical test suites such as Application Notes and Interpretation of the Scheme (AIS20), the Federal Information Processing Standards (FIPS140), CryptX, and so on. However, when it is applied on some well-known good Deterministic Random Bit Generators (DRBGs), the test results show apparent bias from randomness. This shows that there exist some inaccuracies in the runs distribution test. The problem is solved and the runs distribution test through two ways is corrected. First, the degree of freedom of statistical value V is adjusted. Secondly, the expected number of different lengths runs is modified. The experiment results show that the corrected runs distribution test is more accurate under two-level evaluation approach proposed by National Institute of Standards and Technology (NIST) Special Publication (SP) 800–22.

Optical ultrafast random number generation at 1 Tb/s using a turbulent semiconductor ring cavity laser.

A simple method of high-speed random bit generation is presented that utilizes the turbulent output of a fiber ring cavity semiconductor laser. Random bits are generated by multi-bit sampling of the chaotic optical waveform passed through a simple post-processing procedure, leading to generation rates up to and potentially exceeding 1Tb/s. The resulting random bit streams are tested statistically using a software package designed to test random number generators, the NIST statistical test suite. The bit streams pass each of these test sets, indicating their suitability for use in random number generation applications. This novel technique allows the generation of random bits from less complex experimental conditions than previously reported, while improving upon recent previous studies in terms of bit rate and quality of bits.

Random number generation from spontaneous Raman scattering

We investigate the generation of random numbers via the quantum process of spontaneous Raman scattering. Spontaneous Raman photons are produced by illuminating a highly nonlinear chalcogenide glass (As2S3) fiber with a CW laser at a power well below the stimulated Raman threshold. Single Raman photons are collected and separated into two discrete wavelength detuning bins of equal scattering probability. The sequence of photon detection clicks is converted into a random bit stream. Postprocessing is applied to remove detector bias, resulting in a final bit rate of ∼650 kb/s. The collected random bit-sequences pass the NIST statistical test suite for one hundred 1 Mb samples, with the significance level set to α=0.01. The fiber is stable, robust and the high nonlinearity (compared to silica) allows for a short fiber length and low pump power favourable for real world application.

Image forgery detection in contourlet transform domain based on new chaotic cellular automata

AbstractImage authentication includes techniques that detect unauthorized changes in digital pictures. Image authentication is generally categorized into two primary categories, active and passive methods. In this paper, a new active image authentication method is proposed for tamper detection based on contourlet transform. Cellular automata and ‘Game of Life’ are also used to improve the detection of tampered area. A pseudo‐random number generator based on cellular automata has been used to improve security of proposed technique. We evaluates security and randomness of proposed pseudo‐random number generator using by NIST statistical test suite. Experimental results show that the proposed method is sensitive to any tampers, and it can detect forged areas of the images. Visual quality of image after embedding process is desirable due to Peak Signal‐to‐Noise Ratio (PSNR) measure. Copyright © 2015 John Wiley & Sons, Ltd.

Statistical tests on clustered global earthquake synthetic data sets

AbstractWe study the ability of statistical tests to identify nonrandom features of earthquake catalogs, with a focus on the global earthquake record since 1900. We construct four types of synthetic data sets containing varying strengths of clustering, with each data set containing on average 10,000 events over 100 years with magnitudes above M = 6. We apply a suite of statistical tests to each synthetic realization in order to evaluate the ability of each test to identify the sequences of events as nonrandom. Our results show that detection ability is dependent on the quantity of data, the nature of the type of clustering, and the specific signal used in the statistical test. Data sets that exhibit a stronger variation in the seismicity rate are generally easier to identify as nonrandom for a given background rate. We also show that we can address this problem in a Bayesian framework, with the clustered data sets as prior distributions. Using this new Bayesian approach, we can place quantitative bounds on the range of possible clustering strengths that are consistent with the global earthquake data. At M = 7, we can estimate 99th percentile confidence bounds on the number of triggered events, with an upper bound of 20% of the catalog for global aftershock sequences, with a stronger upper bound on the fraction of triggered events of 10% for long‐term event clusters. At M = 8, the bounds are less strict due to the reduced number of events. However, our analysis shows that other types of clustering could be present in the data that we are unable to detect. Our results aid in the interpretation of the results of statistical tests on earthquake catalogs, both worldwide and regionally.

GPUs and chaos: a new true random number generator

For applications where security and unpredictability is of utmost importance, true random number generators (TRNGs) play a heavy role compared to its pseudo-random counterparts. Most TRNGs obtain randomness from physical phenomena such as radio noise, radioactive decay or thermal noise that are unpredictable. These applications usually require external hardware to extract entropy and convert them into digital signals. This paper introduces a TRNGs that utilizes graphics processing units as the source of entropy. Its unpredictable behavior is harnessed by computing chaotic maps that are highly sensitive to slight changes to their control parameters and have pseudo-random behavior. A simple post-processing function based on modular addition and XOR is then used to achieve an unbiased output. The security of the proposed TRNG is evaluated using statistical test suites such as the NIST SP 800-22, DIEHARD and ENT, as well as entropy analysis to determine unpredictability. Results indicate that the proposed TRNG has strong statistical quality of random numbers and high throughput without the need of external specialized equipment.

CUDA 환경에서 CUSUM 검증의 병렬화

We have parallelized the cumulative sum (CUSUM) test of NIST's statistical random number test suite in a CUDA environment. Storing random walks in an array instead of in scalar variables eliminates data dependence. The change in data structure makes it possible to apply parallel scans, scatters, and reductions at each stage of the test. In addition, serial data exchanges between CPU and GPU are removed by migrating CPU's tasks to GPU. Finally we have optimized global memory accesses. The overall speedup is 23 times over the sequential version. Our results contribute to improving security of random numbers for cryptographic keys as well as reducing the time for evaluation of randomness.

Peramorphic males and extreme sexual dimorphism in Monodelphis dimidiata (Didelphidae)

The southern short-tailed opossum, Monodelphis dimidiata, is a species known not only for its semelparous life cycle, but also for the extreme sexual dimorphism of adults, where males are not only larger, but also have distinctive morphological characters in their skull. Using geometric morphometrics and a suite of statistical tests, I analyzed the postweaning ontogenetic development of this species in order to evaluate the age-class where sexual dimorphism becomes significant and the amount of change exhibited by both sexes. My results showed that M. dimidiata partly follows the ontogenetic pattern described for didelphids by previous authors. The character that escapes the general pattern is rostral length, which becomes shorter instead of lengthening throughout the development. This change could be related to an increment in the bite force in the anterior part of the dentition. The amount of sexual dimorphism found for this species is larger than the reported previously for other American marsupials, and I also found a higher rate of growth in males at the attaining of sexual maturity. Based on my results and the information available for other didelphids, I can suggest that M. dimidiata males undergo through a process of hypermorphosis, resulting in a peramorphic condition. It is possible that the extreme sexual dimorphism present in this species is related to reproductive success, specially taking into account their semelparous life cycle.

High-speed quantum-random number generation by continuous measurement of arrival time of photons.

We demonstrate a novel high speed and multi-bit optical quantum random number generator by continuously measuring arrival time of photons with a common starting point. To obtain the unbiased and post-processing free random bits, the measured photon arrival time is converted into the sum of integral multiple of a fixed period and a phase time. Theoretical and experimental results show that the phase time is an independent and uniform random variable. A random bit extraction method by encoding the phase time is proposed. An experimental setup has been built and the unbiased random bit generation rate could reach 128 Mb/s, with random bit generation efficiency of 8 bits per detected photon. The random numbers passed all tests in the statistical test suite.

Design and ARM-Embedded Implementation of a Chaotic Map-Based Real-Time Secure Video Communication System

A systematic methodology is proposed for a chaotic map-based real-time video encryption and decryption system with advanced Reduced Instruction Set Computer machine (ARM)-embedded hardware implementation. According to the anticontrol principle of dynamical systems, first, an 8-D discrete-time chaotic map-based system is constructed, which possesses the required property of 1-1 surjection in the integer range $[{0,\,N-1}]$ , where $N$ is the number of frame pixels, suitable for position scrambling of each video frame. Then, an 8-D discrete-time hyperchaotic system is designed for encryption–decryption of red, green, and blue (RGB) tricolor pixel values. Using the ARM-embedded platform super4412 model with Cortex-A9 processor, together with the standard QT cross-platform, an integrated chaotic map-based real-time secure video communication system is designed, implemented, and evaluated. In addition, the security performance of the designed system is tested using criteria from the National Institute of Standards and Technology statistical test suite. The main feature of this method is that, both scrambling–antiscrambling of RGB tricolor pixel positions and encryption–decryption of pixel values are realized simultaneously for enhancing the security. As is well known, compared with numerical simulations, hardware implementation for such a secure video communication system is very difficult to achieve, but we successfully implemented and tested in a real-world network environment. Both theoretical analysis and experimental results validate the feasibility and real-time performance of the new secure video communication system.

On the Internal Variability of Simulated Daily Precipitation*

Abstract Climate model simulations are currently the main tool to provide information about possible future climates. Apart from scenario uncertainties and model error, internal variability is a major source of uncertainty, complicating predictions of future changes. Here, a suite of statistical tests is proposed to determine the shortest time window necessary to capture the internal precipitation variability in a stationary climate. The length of this shortest window thus expresses internal variability in terms of years. The method is applied globally to daily precipitation in a 200-yr preindustrial climate simulation with the CMCC-CM coupled general circulation model. The two-sample Cramér–von Mises test is used to assess differences in precipitation distribution, the Walker test accounts for multiple testing at grid cell level, and field significance is determined by calculating the Bejamini–Hochberg false-discovery rate. Results for the investigated simulation show that internal variability of daily precipitation is regionally and seasonally dependent and that regions requiring long time windows do not necessarily coincide with areas with large standard deviation. The estimated time scales are longer over sea than over land, in the tropics than in midlatitudes, and in the transitional seasons than in winter and summer. For many land grid cells, 30 seasons suffice to capture the internal variability of daily precipitation. There exist regions, however, where even 50 years do not suffice to sample the internal variability. The results show that diagnosing daily precipitation change at different times based on fixed global snapshots of one climate simulation might not be a robust detection method.

High-Speed Quantum Random Number Generation Using CMOS Photon Counting Detectors

Optical quantum random number generators (QRNGs) are a special class of physical random data sources, whose randomness is established on elementary quantum optics processes. We present a QRNG based on a CMOS chip which overcomes the limitations of the commonly used optical QRNG and which achieves a random bit generation rate up to 200 Mb/s. The CMOS chip is based on an array of single-photon avalanche diodes (SPADs) and digital counters. We prove the absolute randomness of the generated random data through statistical test suites and even more stringent correlation and bias tests applied to 32 Gbit streams. The QRNG passes all tests; hence, it proves to be one of the fastest and more reliable CMOS optical QRNGs currently available.