Drinking fresh water, turning the lights on, travelling
by tram, calling our family, or getting a medical treatment are
usual activities, but the underlying SCADA (Supervisory Control
and Data Acquisition) systems like CIS (Critical Infrastructure
Systems), ICS (Industrial Control Systems) or DCS (Distributed
Control Systems) were always the target of many types of attacks,
endangered the above mentioned simple activities. During the last
decades because of the fast spread of the internet based services
and the continuous technical development these systems become
more vulnerable than ever. Full reconstruction and innovative
changes in older SCADA systems has high cost, and it is not always
rewarding. Communication protocols as Modbus (1979) serve as a
main basis for SCADA systems, so security of Modbus has a major
impact of the security of SCADA systems. Our paper raises and
answers questions about the security of the Modbus RTU protocol.
We focus on the serial Modbus protocol, because in that method
we found many unsolved problems, like lack of authentication of
the participants, lack of secure channel and so on. The aim of this
paper to propose a secure communication alternative for Modbus
RTU @ RS485 wire. The main advantage of the proposed method
is the coexistence with traditional slaves and bus systems and only
software update is necessary
Although self-modifying code has been shyed away
from due to its complexity and discouragement due to safety
issues, it nevertheless provides for a very unique obfuscation
method and a different perspective on the relationship between
data and code. The generality of the von Neumann architecture is
hardly realized by today’s processor models. A code-only model is
shown where every instruction merely modifies other instructions
yet achieves the ability to compute and Turing machine operation
is easily possible.
Games are among problems that can be reduced to
optimization, for which one of the most universal and productive
solving method is a heuristic approach. In this article we present
results of benchmark tests on using 5 heuristic methods to solve
a physical model of the darts game. Discussion of the scores and
conclusions from the research have shown that application of
heuristic methods can simulate artificial intelligence as a regular
player with very good results.
This paper tries to get a response to the following question: When can a narrowband power amplifier (PA) be
considered to be memoryless and when can it not be considered memoryless? To this end, a thorough and consistent analysis of
the notions and definitions related with the above topic is carried out. In the considerations presented, two models of the
narrowband PA are exploited interchangeably: the black box model widely used in the literature and a model developed here,
which is based on the Volterra series. These two models complement each other. In this paper, the conditions for a linear
or nonlinear narrowband PA to be memoryless or approximately memoryless or possessing memory are derived and illustrated.
They are formulated in terms of the signal delay as well as in terms of the amplitude-to-phase (AM/PM) conversion of the
amplifier. Furthermore, the two possible interpretations of the amplitude-to-amplitude (AM/AM) and AM/PM conversions are
given a mathematical framework. That is these conversions are presented through some operations. One set of these operations
allows to treat the AM/AM and AM/PM conversions as distortions of the modulating signals. Or equivalently as
distortions of a given signal constellation when it passes through the PA. Finally, it is proved that the Saleh’s and Ghorbani’s
models of the AM/AM and AM/PM conversions occurring in the PAs, which were published in the literature, are not memoryless
ones.
Inertial navigation is a device, which estimates its position, based on sensing external conditions (such as
acceleration or angular velocity). It is widely used in variuos applications. Its presence in a drone vehicle for example, allows
flight stabilization, by position estimation and feedback-based regulation algorithm execution. A smartphone makes a use of
inertial navigation by detecting movement and flipping screen orientation. It is a ubiquitous part of many devices of everyday
use, but before using filters and algorithms allowing to calculate the position, a calibration must first be applied to the device. This
paper focuses on a separate calibration of each of the sensors - an accelerometer, gyroscope and magnetometer. The further
step requires a cross–sensor calibration, and the third step is implementation of data filtration algotithm.
This paper addresses the problem of efficient searchingfor Nonlinear Feedback Shift Registers (NLFSRs) with a
guaranteed full period. The maximum possible period for an n-bit NLFSR is 2n1 (an all-zero state is omitted). A multi-stages
hybrid algorithm which utilizes Graphics Processor Units (GPU) power was developed for processing data-parallel throughput
computation.
Usage of the abovementioned algorithm allows giving an extended list of n-bit NLFSR with maximum period for 7
cryptographically applicable types of feedback functions
In this article we describe the SHA-3 algorithm and its internal permutation in which potential weaknesses are hidden.
The hash algorithm can be used for different purposes, such aspseudo-random bit sequences generator, key wrapping or one pass
authentication, especially in weak devices (WSN, IoT, etc.). Analysis of the function showed that successful preimage attacksare possible for low round hashes, protection from which only
works with increasing the number of rounds inside the function.When the hash function is used for building lightweight
applications, it is necessary to apply a small number of rounds,which requires additional security measures. This article proposes
a variant improved hash function protecting against preimage attacks, which occur on SHA-3. We suggest using an additional
external randomness sources obtained from a lightweight PRNG or from application of the source data permutation.
Confidential algorithm for the approximate graph vertex covering problem is presented in this article. It can
preserve privacy of data at every stage of the computation, which is very important in context of cloud computing. Security of our
solution is based on fully homomorphic encryption scheme. The time complexity and the security aspects of considered algorithm
are described.
The article is devoted to generation techniques of the new public key crypto-systems, which are based on application
of indistinguishability obfuscation methods to selected private key crypto-systems. The techniques are applied to symmetric
key crypto-system and the target system is asymmetric one. As an input for our approach an implementation of symmetric
block cipher with a given private-key is considered. Different obfuscation methods are subjected to processing. The targetsystem would be treated as a public-key for newly created
public crypto-system. The approach seems to be interesting from theoretical point of view. Moreover, it can be useful for
information protection in a cloud-computing model.
Encryption is one of the most effective methods of
securing data confidentiality, whether stored on hard drives or
transferred (e.g. by e-mail or phone call). In this paper a new state
recovery attack with tabu search is introduced. Based on research
and theoretical approximation it is shown that the internal state
can be recovered after checking 252 internal states for RC4 and
2180 for VMPC.
This paper deals with the phase-shift fault analysis
of stream cipher Grain v1. We assume that the attacker is able
to desynchronize the linear and nonlinear registers of the cipher
during the keystream generation phase by either forcing one of
the registers to clock one more time, while the other register is not
clocked, or by preventing one of the registers from clocking, while
the other register is clocked. Using this technique, we are able to
obtain the full inner state of the cipher in reasonable time (under
12 hours on a single PC) by using 150 bits of unfaulted keystream,
600 bits of faulted keystreams and by correctly guessing 28 bits
of the linear register.
In this paper we introduce a novel encryption technique, which we call PixSel. This technique uses images in
place of literature as the book cipher’s key. Conventional book ciphers possess an unwieldy ciphertext enlargement, creating
ciphertexts multiple times the length of the plaintext. As well, there is often the issue of a given book not containing the
necessary material for the encipherment of some plaintexts. Wesought to rectify these nuisances with PixSel, possessing a typical
ciphertext enlargement of merely 1% to 20% for text. UsingPixSel, there are also no limitations on encipherable data type,
given a suitable image.
We propose the adaptation of Nested Monte-Carlo
Search algorithm for finding differential trails in the class
of ARX ciphers. The practical application of the algorithm
is demonstrated on round-reduced variants of block ciphers
from the SPECK family. More specifically, we report the best
differential trails,up to 9 rounds, for SPECK32.
The convolution operation used in deterministic network calculus differs from its counterpart known from the
classic systems theory. A reason for this lies in the fact that the former is defined in terms of the so-called min-plus algebra.
Therefore, it is oft difficult to realize how it really works. In these cases, its graphical interpretation can be very helpful. This paper
is devoted to a topic of construction of the min-plus convolution curve. This is done here in a systematic way to avoid arriving at
non-transparent figures that are presented in publications. Contrary to this, our procedure is very transparent and removes
shortcomings of constructions known in the literature. Some examples illustrate its usefulness.
This paper presents a new OpenFlow controller: the Distributed Active Information Model (DAIM). The DAIM
controller was developed to explore the viability of a logically distributed control plane. It is implemented in a distributed
way throughout a software-defined network, at the level of the switches. The method enables local process flows, by way of
local packet switching, to be controlled by the distributed DAIM controller (as opposed to a centralised OpenFlow controller).
The DAIM ecosystem is discussed with some sample code, together with flowcharts of the implemented algorithms. We
present implementation details, a testing methodology, and an experimental evaluation. A performance analysis was conducted
using the Cbench open benchmarking tool. Comparisons were drawn with respect to throughput and latency. It is concluded
that the DAIM controller can handle a high throughput, while keeping the latency relatively low. We believe the results to date
are potentially very interesting, especially in light of the fact that a key feature of the DAIM controller is that it is designed to
enable the future development of autonomous local flow process and management strategies.
This paper presents an experimental system for remote communication between road users and traffic signs.
Implemented solution consists of two modules: a transmitter (traffic sign), including novel system for remote waking-up by the
passing vehicle with use of the quasi-passive (biased) diode detector circuit, and a receiver (vehicle), which is responsible for
wake-up signaling and interpreting received messages. Both modules use Wi-Fi protocol operating in 2.4 GHz ISM band for
sending data, and OOK signaling in 868 MHZ ISM band for sending wake-up signals. The paper provides theoretical analysis,
description of design challenges and chosen solutions, and finally, laboratory measurements as well as the results of tests conducted
in the systems’ target environment with a moving vehicle, confirming correct operation of the system.
A significant threat to critical infrastructure of computer systems has a destructive impact caused by infrasound
waves. It is shown that the known infrasound generations are based on using the following devices: a Helmholtz Resonator, Generation
by using a Pulsating Sphere such as Monopolies, Rotor-type Radiator, Resonating Cylinder, VLF Speaker, Method of Paired
Ultrasound Radiator, and airscrew. Research of these devices was made in this paper by revealing their characteristics, main
advantages and disadvantages. A directional pattern of infrasound radiation and a graph of dependence of infrasound radiation from
the consumed power was constructed. Also, during the analysis of these devices, there was proven a set of basic parameters, the values
of which make it possible to characterize their structural and operational characteristics. Then approximate values of the proposed parameters of each those considered devices, were
calculated. A new method was developed for evaluating the effectiveness of infrasound generation devices based on the
definition of the integral efficiency index, which is calculated using the designed parameters. An example of practical application of
the derived method, was shown. The use of the method makes it possible, taking into account the conditions and requirements of
the infrasound generation devices construction, to choose from them the most efficient one.
We propose building a new PKC in a ring structure, the classification of rings being an open problem. The difficulty of
the scheme is based on retrieving the eigenvalues of endomorphism on a finite type module over a non-commutative ring. It is resistant
to a chosen cipher text attack. Working in the fraction ring of a non-commutative ring makes our scheme a zero-knowledge proof
of knowledge, result indistinguishable, in the Naor-Yung model. Finally, a dramatic improvement in security is obtained through
the drawing with uniform probability of the working ring at high frequency.
In this paper, the application of the Artificial Neural Network (ANN) algorithm has been used for testing selected specification
parameters of voltage-controlled oscillator. Today, mixed electronic circuits specification time is an issue. An analog part of Phase Locked Loopis a voltage-controlled oscillator, which is very sensitive to variation of the
technology process. Fault model for the integrated circuit voltage control oscillator (VCO) in ring topology is introduced and the before test stage
classificatory is designed. In order to reduce testing time and keep the specification accuracy (approximation) on the high level, an artificial
neural network has been applied. The features selection process and output coding for specification parameters are described.
A number of different ANN have been designed and then compared with real specification of the VCO. The results obtained gives response in short
time with high enough accuracy.
The subject of this study is the non-repudiation security service for network communication using TCP/IP stack.
Generated evidence, as well as decision-making process of registering a given event, are context-aware. Non-repudiation
is equipped with context-awareness by using widely utilized network tools. The aim of this paper is to present timing
results for selected tools execution and to complete the evidence generation time. In some applications it is crucial to gather
evidence data as fast as possible because of the rapidly changing network environment. For such situations, in case of prolonged
execution time, an output from a tool might imprecisely describe the contextual situation from the time of the occurrence of an
event.
Analysis of harmonic parameters and detection of
foreign frequencies in diagnostic signals, which are most often
interpreted as fault results, may be problematic because of
the spectral leakage effect. When the signal contains only the
fundamental frequency and harmonics, it is possible to adjust
its spectral resolution to eliminate any distortions for regular
frequencies. The paper discusses the influence of resampling
distortions on the quality of spectral resolution optimization in
diagnostic signals, recorded digitally for objects in a steady state.
The method effectiveness is measured with the use of a synthetic
signal generated from an analog prototype whose parameters
are known. In order to achieve low values of harmonic amplitude
errors in the diagnostic signal, a high quality resampling
algorithm should be used, therefore the analysis of distortions
generated by four popular reasampling methods is performed.
Errors are measured for test signals containing different spectral
structures. Finally, the results of the test of the analyzed method
in practical applications are presented.
Video walls are useful to display large size video
content. Empowered video walls combine display functionality
with computing power. Such video walls can display large
scientific visualizations. If they can also display high-resolution
video streamed over a network, they could enable distance
collaboration over scientific data.
We proposed several methods of network streaming of highresolution
video content to a major type of empowered video
walls, which is the SAGE2 system. For all methods, we evaluated
their performance and discussed their scalability and properties.
The results should be applicable to other web-based empowered
video walls as well.
This article provides a comparison of a three methods
that can be used for calculating effective coverage of image
quality assessment database. The aim of this metric is to show
how well the database is filled with variety of images. For
each image in the database the Spatial Information (SI) and
Colorfulness (CF) metric is calculated. The area of convex hull
containing all the points on SI x CF plane is indication of total
coverage of the database, but it does not show how efficiently
this area is utilized. For this purpose an effective coverage was
introduced. An analysis is performed for 16 databases - 13
publicaly available and 3 artificial created for the purpose of
showing advantages of the effective coverage.
Keypoint detection is a basic step in many computer
vision algorithms aimed at recognition of objects, automatic
navigation and analysis of biomedical images. Successful implementation
of higher level image analysis tasks, however, is
conditioned by reliable detection of characteristic image local
regions termed keypoints. A large number of keypoint detection
algorithms has been proposed and verified. In this paper we
discuss the most important keypoint detection algorithms. The
main part of this work is devoted to description of a keypoint
detection algorithm we propose that incorporates depth
information computed from stereovision cameras or other depth
sensing devices. It is shown that filtering out keypoints that
are context dependent, e.g. located at boundaries of objects
can improve the matching performance of the keypoints which
is the basis for object recognition tasks. This improvement is
shown quantitatively by comparing the proposed algorithm to
the widely accepted SIFT keypoint detector algorithm. Our study
is motivated by a development of a system aimed at aiding the
visually impaired in space perception and object identification.