Table Substitution Box Method for Increasing Security in Interval Splitting Arithmetic Coding

Amalgamation of compression and security is indispensable in the field of multimedia applications. A novel approach to enhance security with compression is discussed in this  research paper. In secure arithmetic coder (SAC), security is provided by input and output permutation methods and compression is done by interval splitting arithmetic coding. Permutation in SAC is susceptible to attacks. Encryption issues associated with SAC is dealt in this research method. The aim of this proposed method is to encrypt the data first by Table Substitution Box (T-box) and then to compress by Interval Splitting Arithmetic Coder (ISAC). This method incorporates dynamic T-box in order to provide better security. T-box is a method, constituting elements based on the random output of Pseudo Random Generator (PRNG), which gets the input from Secure Hash Algorithm-256 (SHA-256) message digest. The current scheme is created, based on the key, which is known to the encoder and decoder. Further, T-boxes are created by using the previous message digest as a key.  Existing interval splitting arithmetic coding of SAC is applied for compression of text data. Interval splitting finds a relative position to split the intervals and this in turn brings out compression. The result divulges that permutation replaced by T-box method provides enhanced security than SAC. Data is not revealed when permutation is replaced by T-box method. Security exploration reveals that the data remains secure to cipher text attacks, known plain text attacks and chosen plain text attacks. This approach results in increased security to Interval ISAC. Additionally the compression ratio  is compared by transferring the outcome of T-box  to traditional  arithmetic coding. The comparison proved that there is a minor reduction in compression ratio in ISAC than arithmetic coding. However the security provided by ISAC overcomes the issues of compression ratio in  arithmetic coding.Â

Billiard Dynamics: An Updated Survey with the Emphasis on Open Problems

This is an updated and expanded version of our earlier survey article \cite{Gut5}. Section $\S 1$ introduces the subject matter. Sections $\S 2 - \S 4$ expose the basic material following the paradigm of elliptic, hyperbolic and parabolic billiard dynamics. In section $\S 5$ we report on the recent work pertaining to the problems and conjectures exposed in the survey \cite{Gut5}. Besides, in section $\S 5$ we formulate a few additional problems and conjectures. The bibliography has been updated and considerably expanded

A Distinguisher-Based Attack on a Variant of McEliece's Cryptosystem Based on Reed-Solomon Codes

Baldi et \textit{al.} proposed a variant of McEliece's cryptosystem. The main idea is to replace its permutation matrix by adding to it a rank 1 matrix. The motivation for this change is twofold: it would allow the use of codes that were shown to be insecure in the original McEliece's cryptosystem, and it would reduce the key size while keeping the same security against generic decoding attacks. The authors suggest to use generalized Reed-Solomon codes instead of Goppa codes. The public code built with this method is not anymore a generalized Reed-Solomon code. On the other hand, it contains a very large secret generalized Reed-Solomon code. In this paper we present an attack that is built upon a distinguisher which is able to identify elements of this secret code. The distinguisher is constructed by considering the code generated by component-wise products of codewords of the public code (the so-called "square code"). By using square-code dimension considerations, the initial generalized Reed-Solomon code can be recovered which permits to decode any ciphertext. A similar technique has already been successful for mounting an attack against a homomorphic encryption scheme suggested by Bogdanoc et \textit{al.}. This work can be viewed as another illustration of how a distinguisher of Reed-Solomon codes can be used to devise an attack on cryptosystems based on them.Comment: arXiv admin note: substantial text overlap with arXiv:1203.668

Cryptanalysis of McEliece Cryptosystem Based on Algebraic Geometry Codes and their subcodes

We give polynomial time attacks on the McEliece public key cryptosystem based either on algebraic geometry (AG) codes or on small codimensional subcodes of AG codes. These attacks consist in the blind reconstruction either of an Error Correcting Pair (ECP), or an Error Correcting Array (ECA) from the single data of an arbitrary generator matrix of a code. An ECP provides a decoding algorithm that corrects up to $\frac{d^*-1-g}{2}$ errors, where $d^*$ denotes the designed distance and $g$ denotes the genus of the corresponding curve, while with an ECA the decoding algorithm corrects up to $\frac{d^*-1}{2}$ errors. Roughly speaking, for a public code of length $n$ over $\mathbb F_q$, these attacks run in $O(n^4\log (n))$ operations in $\mathbb F_q$ for the reconstruction of an ECP and $O(n^5)$ operations for the reconstruction of an ECA. A probabilistic shortcut allows to reduce the complexities respectively to $O(n^{3+\varepsilon} \log (n))$ and $O(n^{4+\varepsilon})$. Compared to the previous known attack due to Faure and Minder, our attack is efficient on codes from curves of arbitrary genus. Furthermore, we investigate how far these methods apply to subcodes of AG codes.Comment: A part of the material of this article has been published at the conferences ISIT 2014 with title "A polynomial time attack against AG code based PKC" and 4ICMCTA with title "Crypt. of PKC that use subcodes of AG codes". This long version includes detailed proofs and new results: the proceedings articles only considered the reconstruction of ECP while we discuss here the reconstruction of EC

Causes and consequences of job insecurity in modern societies : temporary employment, employment protection legislation and turnover intentions in a comparative perspective

Job insecurity has many adverse consequences for individuals. In this dissertation, causes and consequences of job insecurity are examined in three studies. The first study examines one consequence – turnover intentions, using data from the International Social Survey Programme and finds that both job insecurity and employability increases turnover intentions in almost all of the 31 countries in the study, while perceived irreplaceability decreases turnover intentions in most. In the second study, two of the most influential determinants of job insecurity – temporary employment and employment protection legislation (EPL) are studied. By using a more elaborate operationalization for EPL than previous research, it can be shown that strong EPL increases the negative effect of temporary employment on perceived job insecurity using data from the European Social Survey 2004 and 2010. The third study examines the commonly used measure for EPL – the EPL-Index published by the OECD – in-depth and develops an indicator in a theory-driven way to closely reflect the theoretical construct of protection against dismissal. Using two examples from labour market reseach, analysing data from the European Social Survey, the European Labour Force Survey, the European Quality of Life Survey and the European Working Conditions Survey, it can be shown, that while the theory-driven new EPL-Index leads to results expected from the literature, the OECD EPL-Index does not

Stress and Olfaction: The Affective Link

Objectives: Odor presence may change the way a visual stimulus is perceived, and emotional state can influence olfaction, or the sense of smell (Zald & Parado,1997; Seubert et. al,2009; Pollatos et. al,2007). Under a negative emotional state, both males and females had decreased olfactory detection sensitivity but only males rated odors as being more unpleasant and intense (Chen & Dalton,2005). No study has examined sex differences in the effects of social and non-social stress on affective state and olfactory functioning. Females experience greater negative affect in response to social stress compared to males, who appear have distress following achievement stress (Stroud et. al,2002). In this project, sex differences in the impact of social stress and achievement stress on affective state and olfactory function will be investigated. Methods: Participants (N=128) will be randomly assigned to either: social or achievement stress condition. All participants will undergo baseline testing of odor detection sensitivity, hedonics, and intensity, then complete a battery of self-report questionnaires assessing affect, rejection sensitivity, and self-esteem. Participants in the social stress condition will undergo one round of Cyberball and participants in the achievement stress condition will take a difficult arithmetic test. Immediately after stress exposure, repeat olfactory testing and battery of questionnaires assessing affect and perceived stress will be administered. Significance: This project will expand the understanding of how affect and olfaction are related, and how sex influences these relations specifically how stress conditions induce negative affect and alter olfactory functioning. Since social impairment is present across a number of psychiatric disorders and olfaction is related to social functioning, understanding the impact of social versus non-social stress on affective state and olfactory function advancements in prevention and treatment of psychiatric disorders can be achieved. Differences between sex regarding olfactory functioning, emotional regulation, and reactions to stresshttps://ecommons.udayton.edu/stander_posters/2743/thumbnail.jp

Parallel Real-Time Computation: Sometimes Quantity Means Quality

The primary purpose of parallel computation is the fast execution of computational tasks that require an inordinate amount of time to perform sequentially. As a consequence, interest in parallel computation to date has naturally focused on the speedup provided by parallel algorithms over their sequential counterparts. The thesis of this paper is that a second equally important motivation for using parallel computers exists. Specifically, the following question is posed: Can parallel computers, thanks to their multiple processors, do more than simply speed up the solution to a problem? We show that within the paradigm of real-time computation, some classes of problems have the property that a solution to a problem in the class, when computed in parallel, is far superior in quality than the best one obtained on a sequential computer. What constitutes a better solution depends on the problem under consideration. Thus, `better' means `closer to optimal' for optimization problems, `more secure' for cryptographic problems, and `more accurate' for numerical problems. Examples from these classes are presented. In each case, the solution obtained in parallel is significantly, provably, and consistently better than a sequential one. It is important to note that the purpose of this paper is not to demonstrate merely that a parallel computer can obtain a better solution to a computational problem than one derived sequentially. The latter is an interesting (and often surprising) observation in its own right, but we wish to go further. It is shown here that the improvement in quality can be arbitrarily high (and certainly superlinear in the number of processors used by the parallel computer). This result is akin to superlinear speedup --- a phenomenon itself originally thought to be impossible

Impact the Knowledge Gap in the Relationship Between the Repercussions of Armed Conflict and Between of Technical and Vocational Education and Training (TVET) An Applied Study in the Yemeni Community Faculties

This study aims to determine the extent of the impact of the relationship when the knowledge gap mediates between the ramifications of conflict and outputs quality Technical and Vocational Education and Training TVET, and to verify the implications of the armed conflict directly and indirectly of in TVET outputs quality in Yemen. This study was based on a mixed methodology quantitative and qualitative. The quantitative study sample was taken in a probabilistic way. The sample consists of (615) respondents, including (60) teachers, (66) employees, and (489) students. Exploratory Factor Analysis EFA was performed used SPSS. The was used Program AMOS to perform confirmatory factor analysis CFA, and by the structural equation modeling (SEM) was analyzed the path of relations between the study variables, checking all kinds of validity, and compound reliability. The qualitative study relied on interviews with (15) academics and employees who are affiliated with TVET and They act represent 3 them focus groups. The study concluded the following results: There is a direct negative relationship between the knowledge gap and TVET outputs quality. This relationship decreases when the knowledge gap mediates between the Ramifications of conflict and TVET outputs quality. and this means that the mediator here is a partial mediator. The results of the study also showed a direct positive relationship between the repercussions of armed conflicts and the knowledge gap