On the security of Cubic UOV and its variants

The unbalanced oil and vinegar signature scheme (UOV) is one of signature schemes whose public key is a set of multivariate quadratic forms. Recently, a new variant of UOV called Cubic UOV was proposed at Inscrypt 2015. It was claimed that the cubic UOV was more efficient than the original UOV and its security was enough. However, an equivalent secret key of the cubic UOV can be recovered easily. In this note, we describe how to recover it. After we posted the first version of this note, Duong et al. proposed two variants of Cubic UOV at ICISC 2016. We also explain their weakness in the second version

On the cryptosystems based on two Eulerian transfor-mations defined over the commutative rings Z2s,s>1Z_{2^s}, s>1.

We suggest the family of ciphers s^E^n, n=2,3,.... with the space of plaintexts (Z*_{2^s})^n, s >1 such that the encryption map is the composition of kind G=G_1A_1G_2A_2 where A_i are the affine transformations from AGL_n(Z_{2^s}) preserving the variety (Z*_{2^s)}^n , Eulerian endomorphism G_i , i=1,2 of K[x_1, x_2,...., x_n] moves x_i to monomial term ϻ(x_1)^{d(1)}(x_2)^{d(2)}...(x_n)^{d(n)} , ϻϵ Z*_{2^s} and act on (Z*_{2^s})^n as bijective transformations. The cipher is converted to a protocol supported cryptosystem. Protocols of Noncommutative Cryptography implemented on the platform of Eulerian endomorphism are used for the delivery of G_i and A_i from Alice to Bob. One can use twisted Diffie-Hellman protocols which security rests on the complexity of Conjugacy Power problem or hidden tame homomorphism protocol which security rests of the word decomposition problem. Instead of the delivery of G_i Alice and Bob can elaborate these transformations via the inverse twisted Diffie-Hellman protocol implemented on the platform of tame Eulerian transformations of (Z*_{2^s})^n. The cost of single protocol is O(n^3) and the cost of the computation of the reimage of used nonlinear map is O(n^2). So the verification of n^t , t≥1 signatures takes time O(n^{t+2}). Instead of inverse twisted Diffie-Hellman protocol correspondents can use inverse hidden tame homomorphism protocol which rests on the complexity of word decomposition for tame Eulerian transformations. We use natural bijections between Z*_{2^s} and Z_{2^{s-1}}, Z*_{2^s} and finite field F_{2^{s-1}} and Z*_{2^s} and Boolean ring B_{s-1} of order 2^{s-1} to modify the family of ciphers or cryptosystems via the change of AGL_n(Z_{2^s}) for the AGL_n(K), where K is one of the rings Z_{2^{s-1}, F_{2^{s-1} and B_{s-1}. New ciphers are defined via the multiplications of two different commutative rings Z_{2^s} and K. It does not allow to treat them as stream ciphers of multivariate cryptography and use corresponding cryptanalytic technique. Adversary is not able to use known cryptanalytical methods such as linearisation attacks. We discuss the option of change the mentioned above elements of AGL_n(Z_{2^s) or AGL_n(K) for nonlinear multivariate transformation F of (Z_{2^s})^n or K^n with the symmetric trapdoor accelerator T, i.e. the piece of information such that the knowledge of T allows to compute the value F(p) in arbitrarily chosen p ϵ P in time O(n^2) and to solve the equation of kind F(x)=c for each c from C in time O(n ^2)

Chapitre 5: Le commerce extérieur

In this favourable external conjuncture, Algeria should evaluate this trade-off: it can either speed up the path of completing the reforms and thus become a market economy or it can edistribute the unprecedented amount of international reserves to soften the cost of the painful restructuring of the last decade without seizing the distorted fundamentals. This conjuncture of high oil price of oil will not last for years, but the more open, competitive and efficient scenario that has been offered by the Association Agreement is the anchor. Moving away from the “rent system” through diversifying the economy and liberalising trade is a long-term challenge that can be favoured by the current improvement, if Algeria can seize the opportunity. For thisreason the role of the EU will be decisive

Skylab lessons learned as applicable to a large space station, 1967-1974

This report records some of the lessons learned during Skylab development. The approach taken is to list lessons which could have wide application in the development of a large space station. The lessons are amplified and explained in light of the background and experiences of the Skylab development

A Review of Resonant Converter Control Techniques and The Performances

paper first discusses each control technique and then gives experimental results and/or performance to highlights their merits. The resonant converter used as a case study is not specified to just single topology instead it used few topologies such as series-parallel resonant converter (SPRC), LCC resonant converter and parallel resonant converter (PRC). On the other hand, the control techniques presented in this paper are self-sustained phase shift modulation (SSPSM) control, self-oscillating power factor control, magnetic control and the H-∞ robust control technique

OBSERVER-BASED-CONTROLLER FOR INVERTED PENDULUM MODEL

This paper presents a state space control technique for inverted pendulum system. The system is a common classical control problem that has been widely used to test multiple control algorithms because of its nonlinear and unstable behavior. Full state feedback based on pole placement and optimal control is applied to the inverted pendulum system to achieve desired design specification which are 4 seconds settling time and 5% overshoot. The simulation and optimization of the full state feedback controller based on pole placement and optimal control techniques as well as the performance comparison between these techniques is described comprehensively. The comparison is made to choose the most suitable technique for the system that have the best trade-off between settling time and overshoot. Besides that, the observer design is analyzed to see the effect of pole location and noise present in the system

A Review of Resonant Converter Control Techniques and The Performances

paper first discusses each control technique and then gives experimental results and/or performance to highlights their merits. The resonant converter used as a case study is not specified to just single topology instead it used few topologies such as series-parallel resonant converter (SPRC), LCC resonant converter and parallel resonant converter (PRC). On the other hand, the control techniques presented in this paper are self-sustained phase shift modulation (SSPSM) control, self-oscillating power factor control, magnetic control and the H-∞ robust control technique

State-Feedback Controller Based on Pole Placement Technique for Inverted Pendulum System

This paper presents a state space control technique for inverted pendulum system using simulation and real experiment via MATLAB/SIMULINK software. The inverted pendulum is difficult system to control in the field of control engineering. It is also one of the most important classical control system problems because of its nonlinear characteristics and unstable system. It has three main problems that always appear in control application which are nonlinear system, unstable and non-minimumbehavior phase system. This project will apply state feedback controller based on pole placement technique which is capable in stabilizing the practical based inverted pendulum at vertical position. Desired design specifications which are 4 seconds settling time and 5 % overshoot is needed to apply in full state feedback controller based on pole placement technique. First of all, the mathematical model of an inverted pendulum system is derived to obtain the state space representation of the system. Then, the design phase of the State-Feedback Controller can be conducted after linearization technique is performed to the nonlinear equation with the aid of mathematical aided software such as Mathcad. After that, the design is simulated using MATLAB/Simulink software. The controller design of the inverted pendulum system is verified using simulation and experiment test. Finally the controller design is compared with PID controller for benchmarking purpose

Sustainability of Olive Oil System

Sustainability, defined as ‘meeting current needs without compromising the future’, is a widely accepted goal across many sectors of society. Sustainability’s criteria and indicators often only regard sustaining present conditions through increased resilience, intended as a system’s capacity to experience shocks while retaining essentially the same functions and structures. However, new sustainability concepts, sometimes referred to as “sustainagility”, also consider the properties and assets of a system that sustains the ability (agility) of agents to adapt and meet their needs in new ways, preparing for future unpredictability and unforeseen changes. Therefore, resilience must coexist with adaptive capacity for real, long-term sustainability. Consumers are paying increasing attention to the sustainability of the food supply chain; thus, sustainable development is necessary for all food processes. Since the olive oil sector has a well-established historical tradition, any change and innovation that aims to obtain a sustainable development not only needs to be analyzed in terms of environmental, economic, and social aspects, it should also be significantly improved and closely monitored. Thus, this Special Issue is a collection of papers that can increase sustainability knowledge in the olive-oil-processing chain, to take a significant step forward in future developments