Academic literature on the topic 'Substitution box'
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Journal articles on the topic "Substitution box"
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Aaruni, P. M., Baby Aleena, Antony Angel, Benny Binsha, and Gopinath Anjaly. "Substitution Box Optimization." Journal of Electronics and Communication Systems 4, no. 3 (2019): 21–24. https://doi.org/10.5281/zenodo.3531510.
Full textAbstract:
<em>The basic principle of encryption is to transform plain data into unintelligible data via a series of steps referred to as an encryption algorithm. The input to this algorithm is called plaintext, and its output encoded version is called as cipher text. Even though there are various algorithms, Advanced Encryption Standard (AES) is adopted due to the availability of optimized hardware components for efficient implementation. The S-Box is one of the critical operations in AES algorithm and it consists of two sub-modules, namely the multiplicative inversion sub-module in GF(2^8) and the Affine transformation sub-module Each input to the S-Box is a 1-byte of intermediate data, x, and the S-Box will generate 1-byte of output S(x).</em><em> There are variety of methods can used to implement AES S box. </em><em>Through this project our aim is to optimize the S box for minimal access time. We are planning to implement an optimized implementation of the S-box in the Verilog HDL. By developing the Verilog code for substitution box by using different methods, compare them and implement the same in hardware using FPGA.</em>
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Alsaif, Haitham, Ramzi Guesmi, Anwar Kalghoum, Badr M. Alshammari, and Tawfik Guesmi. "A Novel Strong S-Box Design Using Quantum Crossover and Chaotic Boolean Functions for Symmetric Cryptosystems." Symmetry 15, no. 4 (2023): 833. http://dx.doi.org/10.3390/sym15040833.
Full textAbstract:
In this paper, we propose a new method for drawing a cryptographically strong substitution box using the Lorenz system and quantum genetic algorithm techniques. We used the chaotic function to generate an initial random sequence of bits and the quantum crossover to provide a new and improved substitution box with increased non-linearity. The aim of the proposed algorithm was to generate a strong and secure substitution box that can be utilized in symmetric cryptosystems. The use of chaotic Boolean functions, genetic algorithm techniques, and the quantum crossover helped achieve this goal, and statistical tests further confirmed the randomness and efficiency of the generated substitution box. The results of the statistical test suite showed that the substitution box produced by the proposed algorithm is a “pass” in terms of randomness and has strong cryptographic properties. The tests include a frequency (monobit) test, a frequency test within a block, a linear complexity test, an approximate entropy test, and a cumulative sums test among others. The p-values obtained in the tests indicate that the randomness of the generated substitution box meets the requirements of a cryptographically secure substitution box.
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Usama, Muhammad, Osama Rehman, Imran Memon, and Safdar Rizvi. "An efficient construction of key-dependent substitution box based on chaotic sine map." International Journal of Distributed Sensor Networks 15, no. 12 (2019): 155014771989595. http://dx.doi.org/10.1177/1550147719895957.
Full textAbstract:
A substitution box is a core component of the popular symmetric-key algorithms. However, the major problem of the conventional substitution boxes is the statistic behavior, which is employed as a fixed-size lookup table. To solve the fixed-size lookup table problem, various substitution box construction methods were proposed with key control, but it is hard to enhance all cryptographic properties, for example, linear and differential probabilities. Thus, chaos is applied for key control in designing robust substitution boxes due to unpredictable and random-like behavior. Moreover, the confusion and diffusion properties of cryptography can be achieved by chaos. This article introduces an efficient construction of a key-dependent substitution box based on the mixing property of the chaotic sine map. The substitution box so constructed has very low differential and linear approximation probabilities. The experimental results confirmed that the proposed method to construct substitution box has acceptable cryptographic properties to resist against various cryptanalysis.
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Jakheer, S. Muhammad, Shaik Jaffar, and Syed Jahangir Badashah. "An Evaluation of Power Analysis Attacks on Asynchronous Substitution Box." International Journal of Scientific Research 2, no. 11 (2012): 217–20. http://dx.doi.org/10.15373/22778179/nov2013/70.
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Bin Faheem, Zaid, Asim Ali, Muhamad Asif Khan, Muhammad Ehatisham Ul‐Haq, and Waqar Ahmad. "Highly dispersive substitution box (S‐box) design using chaos." ETRI Journal 42, no. 4 (2020): 619–32. http://dx.doi.org/10.4218/etrij.2019-0138.
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Ali, Ahmed, Nasir Siddiqui, and Bilal Arshad. "An Elliptic Curve-Based Approach for Construction of Secure Substitution Box." International Journal of Research Publication and Reviews 5, no. 4 (2024): 7473–80. http://dx.doi.org/10.55248/gengpi.5.0424.10112.
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Bakr, Mohamed, and Noha Korany. "Nonlinearity Improvement for Ascon Substitution Box." International Journal of Telecommunications 04, no. 01 (2024): 1–13. http://dx.doi.org/10.21608/ijt.2024.269831.1043.
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Freyre Arrozarena, Pablo, Adrián Alfonso Peñate, Alejandro Freyre Echevarría, and Ramses Rodríguez Aulet. "A new look in the representation of AES like S-box." Journal of Science and Technology on Information security 3, no. 17 (2023): 53–60. http://dx.doi.org/10.54654/isj.v3i17.900.
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Abstract— Substitution box plays an essential role in block ciphers as their main non-linear component in the round function, providing confusion. In this paper, it will be proven how the action of any substitution box on every fixed element can be represented through an affine transformation using an invertible matrix in a finite field. Furthermore, a particular way to represent the action of permutations on every element through a modular addition is given. An analysis of the AES substitution box is conducted based on the theoretical results obtained.
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Rashid, Mamun-Or, Xiao-Yan Zhang, Ying Wang, Da-Wei Li, Jia-Lin Yu, and Cheng-Gui Han. "The Three Essential Motifs in P0 for Suppression of RNA Silencing Activity of Potato leafroll virus Are Required for Virus Systemic Infection." Viruses 11, no. 2 (2019): 170. http://dx.doi.org/10.3390/v11020170.
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Higher plants exploit posttranscriptional gene silencing as a defense mechanism against virus infection by the RNA degradation system. Plant RNA viruses suppress posttranscriptional gene silencing using their encoded proteins. Three important motifs (F-box-like motif, G139/W140/G141-like motif, and C-terminal conserved region) in P0 of Potato leafroll virus (PLRV) were reported to be essential for suppression of RNA silencing activity. In this study, Agrobacterium-mediated transient experiments were carried out to screen the available amino acid substitutions in the F-box-like motif and G139/W140/G141-like motif that abolished the RNA silencing suppression activity of P0, without disturbing the P1 amino acid sequence. Subsequently, four P0 defective mutants derived from a full-length cDNA clone of PLRV (L76F and W87R substitutions in the F-box-like motif, G139RRR substitution in the G139/W140/G141-like motif, and F220R substitution in the C-terminal conserved region) were successfully generated by reverse PCR and used to investigate the impact of these substitutions on PLRV infectivity. The RT-PCR and western blot analysis revealed that these defective mutants affected virus accumulation in inoculated leaves and systemic movement in Nicotiana benthamiana as well as in its natural hosts, potato and black nightshade. These results further demonstrate that the RNA silencing suppressor of PLRV is required for PLRV accumulation and systemic infection.
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Cadieux, Nathalie, Clive Bradbeer, and Robert J. Kadner. "Sequence Changes in the Ton Box Region of BtuB Affect Its Transport Activities and Interaction with TonB Protein." Journal of Bacteriology 182, no. 21 (2000): 5954–61. http://dx.doi.org/10.1128/jb.182.21.5954-5961.2000.
Full textAbstract:
ABSTRACT Uptake of cobalamins by the transporter protein BtuB in the outer membrane of Escherichia coli requires the proton motive force and the transperiplasmic protein TonB. The Ton box sequence near the amino terminus of BtuB is conserved among all TonB-dependent transporters and is the only known site of mutations that confer a transport-defective phenotype which can be suppressed by certain substitutions at residue 160 in TonB. The crystallographic structures of the TonB-dependent transporter FhuA revealed that the region near the Ton box, which itself was not resolved, is exposed to the periplasmic space and undergoes an extensive shift in position upon binding of substrate. Site-directed disulfide bonding in intact cells has been used to show that the Ton box of BtuB and residues around position 160 of TonB approach each other in a highly oriented and specific manner to form BtuB-TonB heterodimers that are stimulated by the presence of transport substrate. Here, replacement of Ton box residues with proline or cysteine revealed that residue side chain recognition is not important for function, although replacement with proline at four of the seven Ton box positions impaired cobalamin transport. The defect in cobalamin utilization resulting from the L8P substitution was suppressed by cysteine substitutions in adjacent residues in BtuB or in TonB. This suppression did not restore active transport of cobalamins but may allow each transporter to function at most once. The uncoupled proline substitutions in BtuB markedly affected the pattern of disulfide bonding to TonB, both increasing the extent of cross-linking and shifting the pairs of residues that can be joined. Cross-linking of BtuB and TonB in the presence of the BtuB V10P substitution became independent of the presence of substrate, indicating an additional distortion of the exposure of the Ton box in the periplasmic space. TonB action thus requires a specific orientation for functional contact with the Ton box, and changes in the conformation of this region block transport by preventing substrate release and repeated transport cycles.
Dissertations / Theses on the topic "Substitution box"
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Yildiz, Senay. "Construction Of Substitution Boxes Depending On Linear Block Codes." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605540/index.pdf.
Full textAbstract:
The construction of a substitution box (S-box) with high nonlinearity and high resiliency is an important research area in cryptography.
In this thesis, t-resilient nxm S-box construction methods depending on linear block codes presented in "<br>A Construction of Resilient Functions with High Nonlinearity"<br>by T. Johansson and E. Pasalic in 2000, and two years later in "<br>Linear Codes in Generalized Construction of Resilient Functions with Very High Nonlinearity"<br>by E. Pasalic and S. Maitra are compared and the
former one is observed to be more promising in terms of nonlinearity. The first construction method uses a set of nonintersecting [n-d,m,t+1] linear block codes in deriving t-resilient S-boxes of nonlinearity 2^(n-1)-2^(n-d-1),where
d is a parameter to be maximized for high nonlinearity. For some cases, we have found better results than the results of Johansson and Pasalic, using their construction.
As a distinguished reference for nxn S-box construction methods, we study the paper "<br>Differentially Uniform Mappings for Cryptography"<br>presented by K.Nyberg in Eurocrypt 1993. One of the two constructions of this paper, i.e., the
inversion mapping described by Nyberg but first noticed in 1957 by L. Carlitz and S. Uchiyama, is used in the S-box of Rijndael, which is chosen as the Advanced Encryption Standard. We complete the details of some theorem and
proposition proofs given by Nyberg.
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Burnett, Linda Dee. "Heuristic Optimization of Boolean Functions and Substitution Boxes for Cryptography." Thesis, Queensland University of Technology, 2005. https://eprints.qut.edu.au/16023/1/Linda_Burnett_Thesis.pdf.
Full textAbstract:
Fundamental to the electronic security of information and communication systems, is the correct use and application of appropriate ciphers. The strength of these ciphers, particularly in their ability to resist cryptanalytic attacks, directly in
uences the overall strength of the entire system. The strength of the underlying cipher is reliant upon a robust structure and the carefully designed interaction between components in its architecture. Most importantly, however, cipher strength is critically dependent on the strength of the individual components of which it is comprised.
Boolean functions and substitution boxes (s-boxes) are among the most common and essential components of ciphers. This is because they are able to provide a cipher with strengthening properties to resist known and potential cryptanalytic attacks. Thus, it is not surprising that significant research effort has been made in trying to develop ways of obtaining boolean functions and substitution boxes with
optimal achievable measures of desirable cryptographic properties. Three of the
main cryptographic properties required by strong boolean functions and s-boxes are nonlinearity, correlation immunity and propagation criteria, with different cryptographic applications requiring different acceptable measures of these and other properties. As combinations of cryptographic properties exhibited by functions
can be conicting, finding cryptographically strong functions often means that a trade-off needs to be made when optimizing property values. Throughout this thesis, the term "optimization" specifically refers to seeking to obtain the best achievable combination of target property values which may be exhibited by boolean functions and s-boxes, regardless of whether the relevant properties are
conflicting or complementary.
This thesis focusses on a particular class of techniques for obtaining strong functions for cryptographic applications, referred to as heuristic methods or, simply, heuristics. Three new heuristic methods, each aimed at generating boolean functions optimizing one or more of the main cryptographic properties mentioned above, in addition to other desirable properties, are presented. The first of the new heuristic methods developed for this thesis focusses on generating boolean functions which are balanced and exhibit very high nonlinearities. Highly nonlinear balanced functions are critical to many cryptographic applications, as they provide good resistance to linear cryptanalytic attacks. This first method is based on the recursive modification of a starting bent function and is shown to be highly successful and efficient at generating numerous such functions, which also exhibit low autocorrelation values, in a very short computational time.
The generation of balanced, correlation immune boolean functions that also exhibit the confl
icting property of high nonlinearity is the focus of the second new heuristic method developed for this thesis. By concatenating selected pairs of lower-dimensional boolean functions together in the Walsh Hadamard transform domain, direct optimization for both resilience and nonlinearity was able to take place at each level towards and for the final function. This second method was able to generate examples of boolean functions with almost all of the best known optimal combinations of target property values. Experiments have shown the success of this method in consistently generating highly nonlinear resilient boolean functions, for a range of orders of resilience, with such functions possessing optimal algebraic degree.
A third new heuristic method, which searches for balanced boolean functions which satisfy a non-zero degree of propagation criteria and exhibit high nonlinearity, is presented. Intelligent bit manipulations in the truth table of starting
functions, based on fundamental relationships between boolean function transforms and measures, provide the design rationale for this method. Two new function generation schemes have been proposed for this method, to efficiently
satisfy the requirements placed on the starting functions utilized in the computational
process. An optional process attempts to increase the algebraic degree of the resulting functions, without sacrificing the optimalities that are achievable. The validity of this method is demonstrated through the success of various
experimental trials.
Switching the focus from single output boolean functions to multiple output boolean functions (s-boxes), the effectiveness of existing heuristic techniques (namely Genetic Algorithm, Hill Climbing Method and combined Genetic Algorithm/Hill Climbing) in primarily being applied to improve the nonlinearity of s-boxes of various dimensions, is investigated. The prior success of these heuristic techniques for improving the nonlinearity of boolean functions has been previously demonstrated, as has the success of hill climbing in isolation when applied to bijective s-boxes. An extension to the bijective s-box optimization work is presented in this thesis. In this new research, a Genetic Algorithm, Hill Climbing Method
and the two in combination are applied to the nonlinearity and autocorrelation optimization of regular NxM s-boxes (N > M) to investigate the effectiveness and efficiency of each of these heuristics. A new breeding scheme, utilized in the Genetic Algorithm and combined Genetic Algorithm/Hill Climbing trials, is also presented. The success of experimental results compared to random regular s-box generation is demonstrated.
New research in applying the Hill Climbing Method to construct NxM sboxes (N > M) required to meet specific property criteria is presented. The consideration of the characteristics desired by the constructed s-boxes largely dictated the generation process. A discussion on the generation process of the component functions is included. Part of the results produced by experimental trials were incorporated into a commonly used family of stream ciphers, thus further supporting the use of heuristic techniques as a useful means of obtaining strong functions suitable for incorporation into practical ciphers.
An analysis of the cryptographic properties of the s-box used in the MARS block cipher, the method of generation and the computational time taken to obtain this s-box, led to the new research reported in this thesis on the generation of MARS-like s-boxes. It is shown that the application of the Hill Climbing
Method, with suitable requirements placed on the component boolean functions, was able to generate multiple MARS-like s-boxes which satisfied the MARS sbox requirements and provided additional properties. This new work represented an alternative approach to the generation of s-boxes satisfying the MARS sbox
property requirements but which are cryptographically superior and can be obtained in a fraction of the time than that which was taken to produce the MARS s-box. An example MARS-like s-box is presented in this thesis.
The overall value of heuristic methods in generating strong boolean functions and substitution boxes is clearly demonstrated in this thesis. This thesis has made several significant contributions to the field, both in the development of new, specialized heuristic methods capable of generating strong boolean functions, and in the analysis and optimization of substitution boxes, the latter achieved
through applying existing heuristic techniques.
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Burnett, Linda Dee. "Heuristic Optimization of Boolean Functions and Substitution Boxes for Cryptography." Queensland University of Technology, 2005. http://eprints.qut.edu.au/16023/.
Full textAbstract:
Fundamental to the electronic security of information and communication systems, is the correct use and application of appropriate ciphers. The strength of these ciphers, particularly in their ability to resist cryptanalytic attacks, directly in uences the overall strength of the entire system. The strength of the underlying cipher is reliant upon a robust structure and the carefully designed interaction between components in its architecture. Most importantly, however, cipher strength is critically dependent on the strength of the individual components of which it is comprised. Boolean functions and substitution boxes (s-boxes) are among the most common and essential components of ciphers. This is because they are able to provide a cipher with strengthening properties to resist known and potential cryptanalytic attacks. Thus, it is not surprising that significant research effort has been made in trying to develop ways of obtaining boolean functions and substitution boxes with optimal achievable measures of desirable cryptographic properties. Three of the main cryptographic properties required by strong boolean functions and s-boxes are nonlinearity, correlation immunity and propagation criteria, with different cryptographic applications requiring different acceptable measures of these and other properties. As combinations of cryptographic properties exhibited by functions can be conicting, finding cryptographically strong functions often means that a trade-off needs to be made when optimizing property values. Throughout this thesis, the term "optimization" specifically refers to seeking to obtain the best achievable combination of target property values which may be exhibited by boolean functions and s-boxes, regardless of whether the relevant properties are conflicting or complementary. This thesis focusses on a particular class of techniques for obtaining strong functions for cryptographic applications, referred to as heuristic methods or, simply, heuristics. Three new heuristic methods, each aimed at generating boolean functions optimizing one or more of the main cryptographic properties mentioned above, in addition to other desirable properties, are presented. The first of the new heuristic methods developed for this thesis focusses on generating boolean functions which are balanced and exhibit very high nonlinearities. Highly nonlinear balanced functions are critical to many cryptographic applications, as they provide good resistance to linear cryptanalytic attacks. This first method is based on the recursive modification of a starting bent function and is shown to be highly successful and efficient at generating numerous such functions, which also exhibit low autocorrelation values, in a very short computational time. The generation of balanced, correlation immune boolean functions that also exhibit the confl icting property of high nonlinearity is the focus of the second new heuristic method developed for this thesis. By concatenating selected pairs of lower-dimensional boolean functions together in the Walsh Hadamard transform domain, direct optimization for both resilience and nonlinearity was able to take place at each level towards and for the final function. This second method was able to generate examples of boolean functions with almost all of the best known optimal combinations of target property values. Experiments have shown the success of this method in consistently generating highly nonlinear resilient boolean functions, for a range of orders of resilience, with such functions possessing optimal algebraic degree. A third new heuristic method, which searches for balanced boolean functions which satisfy a non-zero degree of propagation criteria and exhibit high nonlinearity, is presented. Intelligent bit manipulations in the truth table of starting functions, based on fundamental relationships between boolean function transforms and measures, provide the design rationale for this method. Two new function generation schemes have been proposed for this method, to efficiently satisfy the requirements placed on the starting functions utilized in the computational process. An optional process attempts to increase the algebraic degree of the resulting functions, without sacrificing the optimalities that are achievable. The validity of this method is demonstrated through the success of various experimental trials. Switching the focus from single output boolean functions to multiple output boolean functions (s-boxes), the effectiveness of existing heuristic techniques (namely Genetic Algorithm, Hill Climbing Method and combined Genetic Algorithm/Hill Climbing) in primarily being applied to improve the nonlinearity of s-boxes of various dimensions, is investigated. The prior success of these heuristic techniques for improving the nonlinearity of boolean functions has been previously demonstrated, as has the success of hill climbing in isolation when applied to bijective s-boxes. An extension to the bijective s-box optimization work is presented in this thesis. In this new research, a Genetic Algorithm, Hill Climbing Method and the two in combination are applied to the nonlinearity and autocorrelation optimization of regular NxM s-boxes (N > M) to investigate the effectiveness and efficiency of each of these heuristics. A new breeding scheme, utilized in the Genetic Algorithm and combined Genetic Algorithm/Hill Climbing trials, is also presented. The success of experimental results compared to random regular s-box generation is demonstrated. New research in applying the Hill Climbing Method to construct NxM sboxes (N > M) required to meet specific property criteria is presented. The consideration of the characteristics desired by the constructed s-boxes largely dictated the generation process. A discussion on the generation process of the component functions is included. Part of the results produced by experimental trials were incorporated into a commonly used family of stream ciphers, thus further supporting the use of heuristic techniques as a useful means of obtaining strong functions suitable for incorporation into practical ciphers. An analysis of the cryptographic properties of the s-box used in the MARS block cipher, the method of generation and the computational time taken to obtain this s-box, led to the new research reported in this thesis on the generation of MARS-like s-boxes. It is shown that the application of the Hill Climbing Method, with suitable requirements placed on the component boolean functions, was able to generate multiple MARS-like s-boxes which satisfied the MARS sbox requirements and provided additional properties. This new work represented an alternative approach to the generation of s-boxes satisfying the MARS sbox property requirements but which are cryptographically superior and can be obtained in a fraction of the time than that which was taken to produce the MARS s-box. An example MARS-like s-box is presented in this thesis. The overall value of heuristic methods in generating strong boolean functions and substitution boxes is clearly demonstrated in this thesis. This thesis has made several significant contributions to the field, both in the development of new, specialized heuristic methods capable of generating strong boolean functions, and in the analysis and optimization of substitution boxes, the latter achieved through applying existing heuristic techniques.
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Talk, Ruaa. "Deprotonation-substitution of N-Boc-tetrahydroisoquinolines." Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/19202/.
Full textAbstract:
Tetrahydroisoquinolines (THIQs) are found in a wide range of natural products and compounds with biological activity. This thesis describes the methodology of deprotonation‒substitution as an efficient route to 1-substituted THIQs and 3-substituted THIQs. This methodology was developed by using organolithium and organomagnesium chemistry. Firstly, methods were developed for the lithiation–substitution of tetrahydroisoquinolines by carrying out in situ ReactIR spectroscopic monitoring of deprotonation reactions. Moderate to high yields of products were obtained under the optimum reaction conditions. The lithiation‒substitutions of tetrahydroisoquinolines A were carried out. This chemistry was applied to a short synthesis of the alkaloids (±)-dysoxyline and (±)-crispine A. The lithiation–substitution of N-Boc-3-phenyltetrahydroisoquinoline B was also investigated. Lithiation was found to occur with approximately a 2:1 ratio at C-1 to C-3. NMR studies and DFT analysis were carried out in order to calculate the ratio of the two rotamers of B. Investigations have also focused on N-Boc-3-cyanotetrahydroisoquinoline and N-Boc-2-cyanopyrrolidine. High enantioselectivities of the forming products could be obtained from the sequence of deprotonation–substitution of these compounds at –104 ºC using magnesium bases. Altering the solvent was shown to have a large impact on the yield and enantioselectivity of the products.
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Loshchilov, Ilya. "Surrogate-Assisted Evolutionary Algorithms." Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00823882.
Full textAbstract:
Les Algorithmes Évolutionnaires (AEs) ont été très étudiés en raison de leur capacité à résoudre des problèmes d'optimisation complexes en utilisant des opérateurs de variation adaptés à des problèmes spécifiques. Une recherche dirigée par une population de solutions offre une bonne robustesse par rapport à un bruit modéré et la multi-modalité de la fonction optimisée, contrairement à d'autres méthodes d'optimisation classiques telles que les méthodes de quasi-Newton. La principale limitation de AEs, le grand nombre d'évaluations de la fonction objectif, pénalise toutefois l'usage des AEs pour l'optimisation de fonctions chères en temps calcul. La présente thèse se concentre sur un algorithme évolutionnaire, Covariance Matrix Adaptation Evolution Strategy (CMA-ES), connu comme un algorithme puissant pour l'optimisation continue boîte noire. Nous présentons l'état de l'art des algorithmes, dérivés de CMA-ES, pour résoudre les problèmes d'optimisation mono- et multi-objectifs dans le scénario boîte noire. Une première contribution, visant l'optimisation de fonctions coûteuses, concerne l'approximation scalaire de la fonction objectif. Le meta-modèle appris respecte l'ordre des solutions (induit par la valeur de la fonction objectif pour ces solutions) ; il est ainsi invariant par transformation monotone de la fonction objectif. L'algorithme ainsi défini, saACM-ES, intègre étroitement l'optimisation réalisée par CMA-ES et l'apprentissage statistique de meta-modèles adaptatifs ; en particulier les meta-modèles reposent sur la matrice de covariance adaptée par CMA-ES. saACM-ES préserve ainsi les deux propriété clé d'invariance de CMA-ES~: invariance i) par rapport aux transformations monotones de la fonction objectif; et ii) par rapport aux transformations orthogonales de l'espace de recherche. L'approche est étendue au cadre de l'optimisation multi-objectifs, en proposant deux types de meta-modèles (scalaires). La première repose sur la caractérisation du front de Pareto courant (utilisant une variante mixte de One Class Support Vector Machone (SVM) pour les points dominés et de Regression SVM pour les points non-dominés). La seconde repose sur l'apprentissage d'ordre des solutions (rang de Pareto) des solutions. Ces deux approches sont intégrées à CMA-ES pour l'optimisation multi-objectif (MO-CMA-ES) et nous discutons quelques aspects de l'exploitation de meta-modèles dans le contexte de l'optimisation multi-objectif. Une seconde contribution concerne la conception d'algorithmes nouveaux pour l'optimi\-sation mono-objectif, multi-objectifs et multi-modale, développés pour comprendre, explorer et élargir les frontières du domaine des algorithmes évolutionnaires et CMA-ES en particulier. Spécifiquement, l'adaptation du système de coordonnées proposée par CMA-ES est couplée à une méthode adaptative de descente coordonnée par coordonnée. Une stratégie adaptative de redémarrage de CMA-ES est proposée pour l'optimisation multi-modale. Enfin, des stratégies de sélection adaptées aux cas de l'optimisation multi-objectifs et remédiant aux difficultés rencontrées par MO-CMA-ES sont proposées.
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Bayer, Tomáš. "Návrh hardwarového šifrovacího modulu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218076.
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This diploma’s thesis discourses the cryptographic systems and ciphers, whose function, usage and practical implementation are analysed. In the first chapter basic cryptographic terms, symmetric and asymetric cryptographic algorithms and are mentioned. Also usage and reliability are analysed. Following chapters mention substitution, transposition, block and stream ciphers, which are elementary for most cryptographic algorithms. There are also mentioned the modes, which the ciphers work in. In the fourth chapter are described the principles of some chosen cryptographic algorithms. The objective is to make clear the essence of the algorithms’ behavior. When describing some more difficult algorithms the block scheme is added. At the end of each algorithm’s description the example of practical usage is written. The chapter no. five discusses the hardware implementation. Hardware and software implementation is compared from the practical point of view. Several design instruments are described and different hardware design programming languages with their progress, advantages and disadvantages are mentioned. Chapter six discourses the hardware implementation design of chosen ciphers. Concretely the design of stream cipher with pseudo-random sequence generator is designed in VHDL and also in Matlab. As the second design was chosen the block cipher GOST, which was designed in VHDL too. Both designs were tested and verified and then the results were summarized.
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Vorms, Evgeniia. "Cinétique de l’oxydation de l’hydrate d’hydrazine et d’autres combustibles sans carbone sur électrode de nickel." Electronic Thesis or Diss., Strasbourg, 2025. http://www.theses.fr/2025STRAF003.
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La production d'énergie électrochimique à partir de combustibles sans carbone a récemment suscité un grand intérêt. Ce manuscrit se concentre sur l'étude du mécanisme de la réaction d'oxydation de l'hydrazine (HHOR) sur des électrodes de Ni et le compare avec ceux des réactions d'oxydation du borohydrure et de l’ammoniac-borane (BOR, ABOR). Les sites métalliques de Ni ont été identifiés comme les sites catalytiques pour la HHOR, la BOR et l'ABOR, tandis que la présence de sites de Ni (hydr)oxydés a un effet négatif sur l'activité sans influencer clairement le mécanisme réactionnel. Sur la base des résultats de calculs DFT, de la modélisation microcinétique et de mesures DEMS en ligne, un mécanisme de la HHOR sur Ni a été proposé. Celui-ci implique la réaction directe de l'hydrazine dissoute avec des espèces Ni-OH adsorbées, formant un intermédiaire N2Hx,ad (x<4), qui est ensuite oxydé électrochimiquement, conduisant à la formation de N2 et d’eau<br>Electrochemical energy production from carbon-free fuels has recently attracted much attention. This manuscript focuses on studying the mechanism of the hydrazine oxidation reaction (HHOR) on Ni electrodes and comparing it with the ones of the borohydride and ammonia-borane oxidation reactions (BOR, ABOR). Metallic Ni sites were identified as the catalytic sites for the HHOR, BOR, and ABOR, while the presence of Ni (hydr)oxide sites was found to negatively affect activity without a clear influence on the reaction mechanism. Based on the results of DFT calculations, microkinetic modelling, and online DEMS measurements, a mechanism for HHOR on Ni was proposed. It involves the direct reaction of dissolved hydrazine with adsorbed Ni-OH species forming N2Hx,ad (x<4) intermediate, which is subsequently electrochemically oxidized, leading to the formation of N2 and water
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Costa, Filho Francisco Bernardes. "A implementação do Instituto da Substituição Tributária em larga escala pelo estado de São Paulo a partir do ano de 2008 e os conceitos preconizados por Joseph Stiglitz sobre uma boa tributação." reponame:Repositório Institucional do FGV, 2016. http://hdl.handle.net/10438/17224.
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Previous issue date: 2016-09-12<br>Originally, the tax substitution (ST) of the State Value Added Tax (Imposto sobre Circulação de Mercadorias e Serviços - ICMS) was conceived / designed to be applied only to sectors of the economy which traded products classified as commodities, with few producing industries and sectors with products with little variety of items and large number of distribution points and sale. This logic made sense from an economic point of view as well as the tax collection efficiency point of view. It turns out that from the year 2008, several Brazilian states, led by the state of São Paulo, expanded the application of the tax substitution for almost all sectors of the economy. This study, using as main methodology, literature, doctrinal and legislative study and collection of collection of data through public portals and industry associations information, aims to analyze whether economic efficiency in the collection of taxes generated by implementation on a large scale, the institute of tax substitution for the ICMS by the government of the state of São Paulo, from 2008, also brought benefits of efficiency and competitiveness for companies from São Paulo, considering the concepts advocated by Joseph Stiglitz on a good taxation.<br>Originalmente, a substituição tributária (ST) do Imposto sobre Operações de Circulação de Mercadorias e Prestação de Serviços de Transporte Interestadual e Intermunicipal e de Comunicação (ICMS) foi concebido/desenhado para ser aplicado apenas para setores da economia que comercializavam produtos classificados como commodities, com poucas indústrias produtoras e setores com produtos com pouca variedade de itens e com grande número de pontos de distribuição e venda. Uma lógica que fazia sentido tanto do ponto de vista econômico bem como do ponto de vista de eficiência da arrecadação tributária. Ocorre que a partir do ano de 2008, vários estados brasileiros, liderados pelo estado de São Paulo, expandiram a aplicação da substituição tributária para quase todos os setores da economia. O presente trabalho, utilizando como metodologia principal, o estudo bibliográfico, doutrinário e legislativo, bem como a coleta de dados de arrecadação por meio de portais públicos e informações de Associações Industriais, tem como objetivo analisar se eficiência econômica na arrecadação de tributos gerada pela implementação, em larga escala, do instituto da substituição tributária para o ICMS pelo governo do estado de São Paulo, a partir de 2008, também trouxe benefícios de eficiência e competitividade para as empresas paulistas, considerando os conceitos preconizados por Joseph Stiglitz sobre uma boa tributação.
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Kao, Shih-Ting, and 高仕庭. "A Study on Streaming Encryption Scheme with Pseudo Random Number-based Substitution Box." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/21571997901451671328.
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碩士<br>國防大學管理學院<br>資訊管理學系<br>101<br>As information technology progressing, information security becomes more important. Data encryption is a good solution to assure data confidentiality. Usually, symmetric encryption schemes are used to encrypt large amounts of data; moreover, basing on data encryption length, encryption schemes can be divided into two categories, block encryption and streaming encryption. Since more streaming applications are available over the Internet; a symmetric streaming encryption would become more important to handle streaming data encryption.This study tries to propose a symmetric streaming encryption scheme that bases on a data substitution measure to encrypt streaming data. In the proposed encryption scheme, 3 different sizes, 2 bits, 4 bits and 8 bits, of dynamic substitution boxes (S-box) / Inverse substitution boxes (IS-box) are generated with pseudo random numbers. With generated dynamic S-boxes/IS-boxes, the proposed encryption scheme uses generated dynamic S-boxes/IS-boxes to encrypt / decrypt data. Moreover, two substitution measures, full substitution and partial substitution, are available in the proposed encryption scheme.This study implements a prototype program of the proposed encryption scheme with C. Several scenarios are executed to understand the proposed encryption scheme encryption / decryption performance with different sizes of S-box / ISbox and S-box / ISbox generation frequencies. According to collected encryption / decryption execution data, we find that the proposed encryption scheme can receive the best encryption / decryption speed with 2 bits Sboxes / ISboxes and the proposed encryption scheme can receive the best scrambling result with 8 bits Sboxes / ISboxes.
Keywords: Pseudo random number, Substitution boxes (S-box) / Inverse substitution boxes (IS-box), Sizes of S-box / IS-box
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Landmann, Johannes. "Cyanoborate: Synthesen, Ionische Flüssigkeiten und Koordinationsverbindungen sowie die Chemie des Bor-zentrierten Nukleophils B(CN)\(_3\)\(^2\)\(^-\)." Doctoral thesis, 2018. https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-155469.
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Diese Arbeit beschäftigt sich mit der Synthese, Reaktivität und den physikalischen Eigenschaften verschiedener Cyanoborate. Es gelang die optimierte Synthese des Tricyanofluoroborates M[BF(CN)3] (M = Na, K) mittels Lewis-Säure-Katalyse. Aus diesem Borat wurde mittels Reduktion das Bor-zentrierte Nukleophil B(CN)3 2− hergestellt, welches ebenfalls über die äußerst ungewöhnliche Depronotierung des [BH(CN)3]− -Anions zugänglich ist. Das B(CN)3 2− -Dianion wurde erfolgreich mit diversen Elektrophilen wie z.B. Alkylhalogeniden, CO2, CN+-Quellen sowie per- und teilfluorierten Aromaten umgesetzt. Darüber hinaus ergibt die Synthese mit Tricyanohalogenoborat-Anionen das ungewöhnlich stabile gekoppelte Diborat-Dianion [B2(CN)6]2−, welches über einen SN2-Mechanismus entsteht und eine elektronenpräzise B-B-Bindung aufweist. Ferner wurden Ionische Flüssigkeiten mit Perfluoraklylcyanoboraten hergestellt und die physikalischen Parameter systematisch und ausführlich untersucht<br>In this work the syntheses, reactivity and physical properties of different cyanoborates are presented. The synthesis of the tricyanofluoroborates M[BF(CN)3] (M = Na, K) was optimized via a Lewis-acid-catalysis. Reducing this anion resulted in the formation of the boron-centered nucleophile B(CN)3 2−, which is accessible by the highly unusual deprotonation of [BH(CN)3]−, too. The B(CN)3 2− -dianion was successfully treated with various electrophiles such as alkylhalides, CO2, CN+ -sources as well as partly and perfluorinated arenes. Moreover, the synthesis with halidotricyanoborate anions provide the unusually stable coupled diborat-dianion [B2 (CN)6]2−, which is formed via a SN2-mechanismusm and exhibits an electron-precise B-B-bond. Furthermore, Ionic Liquids based on perlfuorocyanoborates were synthesized and their physical properties were studied systematically in detail
Books on the topic "Substitution box"
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Tan, Yeling. Disaggregating China, Inc. Cornell University Press, 2021. http://dx.doi.org/10.7591/cornell/9781501759635.001.0001.
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Set in the aftermath of China's entry into the World Trade Organization (WTO), this book questions the extent to which the liberal internationalist promise of membership has been fulfilled in China. The book unpacks the policies that various Chinese government actors adopted in response to WTO rules and shows that rather than disciplining the state, WTO entry provoked a divergence of policy responses across different parts of the complex party-state. It argues that these responses draw from three competing strategies of economic governance: market-substituting (directive), market-shaping (developmental), and market-enhancing (regulatory). The book uses innovative web-scraping techniques to assemble an original dataset of over 43,000 Chinese industry regulations, identifying policies associated with each strategy. Combining textual analysis with industry data, in-depth case studies, and field interviews with industry representatives and government officials, the book demonstrates that different Chinese state actors adopted different logics of adjustment to respond to the common shock of WTO accession. This policy divergence originated from a combination of international and domestic forces. The book breaks open the black box of the Chinese state, explaining why WTO rules, usually thought to commit states to international norms, instead provoked responses that the architects of those rules neither expected nor wanted.
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The new annotated Sherlock Holmes: Volume II: The return of Sherlock Holmes; His last bow; The case-book of Sherlock Holmes. W. W. Norton & Company, 2005.
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Conan, Doyle A. Complete Sherlock Holms: Return,Memories,Adventures,Valley of Fear and His Last Bow,Case-Book,Hound of Baskerville and Study in Scarlet and Sign of Four. Independently Published, 2021.
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Conan, Doyle Arthur. Complete Sherlock Holmes Collection - Unabridged: A Study in Scarlet - the Sign of the Four - the Adventures of Sherlock Holmes - the Memoirs of Sherlock Holmes - the Hound of the Baskervilles - the Return of Sherlock Holmes - His Last Bow - the Valley of Fear - the Casebook of Sherlock Holmes. Ft. Raphael Publishing Company, 2023.
Find full textBook chapters on the topic "Substitution box"
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Baksi, Anubhab, Sylvain Guilley, Ritu-Ranjan Shrivastwa, and Sofiane Takarabt. "From Substitution Box to Threshold." In Lecture Notes in Computer Science. Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-56232-7_3.
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Ahmad, Musheer, Danish Raza Rizvi, and Zishan Ahmad. "PWLCM-Based Random Search for Strong Substitution-Box Design." In Advances in Intelligent Systems and Computing. Springer India, 2015. http://dx.doi.org/10.1007/978-81-322-2517-1_45.
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Jithendra, K. B., and T. K. Shahana. "High-Security Pipelined Elastic Substitution Box with Embedded Permutation Facility." In Advances in Intelligent Systems and Computing. Springer Singapore, 2016. http://dx.doi.org/10.1007/978-981-10-0419-3_10.
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Agrawal, Deepak. "Construction of Substitution Box from Nordstrom–Robinson $$(\mathcal N_{16})$$ Code." In Data Science and Applications. Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-99-7820-5_39.
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Jithendra, K. B., and T. K. Shahana. "Elastic Serial Substitution Box for Block Ciphers with Integrated Hash Function Generation." In Proceedings of SAI Intelligent Systems Conference (IntelliSys) 2016. Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-56991-8_48.
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Pientka, Brigitte, and Ulrich Schöpp. "Semantical Analysis of Contextual Types." In Lecture Notes in Computer Science. Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-45231-5_26.
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AbstractWe describe a category-theoretic semantics for a simply typed variant of Cocon, a contextual modal type theory where the box modality mediates between the weak function space that is used to represent higher-order abstract syntax (HOAS) trees and the strong function space that describes (recursive) computations about them. What makes Cocon different from standard type theories is the presence of first-class contexts and contextual objects to describe syntax trees that are closed with respect to a given context of assumptions. Following M. Hofmann’s work, we use a presheaf model to characterise HOAS trees. Surprisingly, this model already provides the necessary structure to also model Cocon. In particular, we can capture the contextual objects of Cocon using a comonad $$\flat $$ ♭ that restricts presheaves to their closed elements. This gives a simple semantic characterisation of the invariants of contextual types (e.g. substitution invariance) and identifies Cocon as a type-theoretic syntax of presheaf models. We express our category-theoretic constructions by using a modal internal type theory that is implemented in Agda-Flat.
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Dey, Sankhanil, and Ranjan Ghosh. "4, 8, 32, 64 Bit Substitution Box Generation Using Irreducible or Reducible Polynomials Over Galois Field GF(Pq) for Smart Applications." In Security in Smart Cities: Models, Applications, and Challenges. Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-030-01560-2_12.
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Xie, Wanting, Sitong Liu, Jianning Guo, Simai Huang, and Shuyu Zhang. "Cultivations and Substitutions of Social Media: A Case Study of the Box Puppy Trend Among Chinese College Students." In Advances in Social Science, Education and Humanities Research. Atlantis Press SARL, 2023. http://dx.doi.org/10.2991/978-2-38476-062-6_34.
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Alvarenga, Valdeci Paula, Varadarajan Seshadri, Itavahn Alves da Silva, Carlos Antonio da Silva, Filipe Bueno Carvalho, and Sergio Luiz Costa. "Use of Recycled Fluxes Substituting Fluorspar for Refining Operation in a Bof Reactor." In 6th International Symposium on High-Temperature Metallurgical Processing. John Wiley & Sons, Inc., 2015. http://dx.doi.org/10.1002/9781119093381.ch58.
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Alvarenga, Valdeci Paula, Varadarajan Seshadri, Itavahn Alves da Silva, Carlos Antonio da Silva, Filipe Bueno Carvalho, and Sergio Luiz Costa. "Use of Recycled Fluxes Substituting Fluorspar for Refining Operation in a BOF Reactor." In 6th International Symposium on High-Temperature Metallurgical Processing. Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-48217-0_58.
Full textConference papers on the topic "Substitution box"
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Hanif, Fozia, Rehan Shams, and Urooj Waheed. "Lightweight security Mechanism for IoT Applications using Substitution-Box." In 2025 IEEE 4th International Conference on AI in Cybersecurity (ICAIC). IEEE, 2025. https://doi.org/10.1109/icaic63015.2025.10848682.
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Baganha, Fernando Sales, Thamara Dias Fernandes, Daniela Melo Vianna Ferrer, Polyanne Martins da Silva, and Flávia Aline Andrade Calixto. ""DESENVOLVIMENTO E AVALIAÇÃO SENSORIAL DE BEBIDA LÁCTEA FERMENTADA COM ADIÇÃO DE MUCILAGEM DE CHIA (SALVIA HISPANICA) UTILIZANDO LEITELHO COMO SUBSTITUTO PARCIAL DO LEITE"." In XXXIII Jornada Científica da Medicina Veterinária. Even3, 2025. https://doi.org/10.29327/1505793.33-16.
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"A demanda por alimentos mais saudáveis tem aumentado, levando à busca por alternativas sustentáveis para produtos tradicionais. Um exemplo são as bebidas lácteas fermentadas, amplamente apreciadas por seus benefícios à saúde, ricas em probióticos e nutrientes. O aproveitamento de subprodutos como soro do queijo e leitelho em sua formulação não apenas contribui para a sustentabilidade, como adiciona valor nutricional e funcional ao produto. Este estudo teve como objetivo desenvolver uma bebida láctea fermentada utilizando leitelho como substituto parcial do leite, mucilagem de chia em substituição a espessantes sintéticos e polpa de goiaba, visando agregar valor nutricional e melhorar as propriedades funcionais da bebida. O experimento foi conduzido no Laboratório de Produtos de Origem Animal do Centro Universitário Serra dos Órgãos, Teresópolis, RJ. Para a avaliação sensorial, voluntários recrutados entre alunos e funcionários participaram de um teste de aceitação, na qual avaliaram a bebida láctea fermentada em cinco critérios: sabor, textura, aroma, aparência e impressão global. Os resultados indicaram boa aceitação da bebida, especialmente em termos de sabor e textura. Conclui-se que a utilização de leitelho como substituto parcial do leite e a mucilagem de chia como espessante natural pode substituir ingredientes tradicionais em bebidas lácteas fermentadas, representando uma alternativa sustentável para as indústrias de produtos lácteos. Palavras-chave: Produtos lácteos. Leitelho. Soro de queijo. Mucilagem de chia. Polpa de fruta."
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Martins, Maysa Lorena Figueiredo, Marcio Mateus Pimenta, and Augusto Cesar da Silva Bezerra. "Aproveitamento de resíduos da indústria alimentícia para a produção de materiais cimentícios sustentáveis." In XX ENCONTRO NACIONAL DE TECNOLOGIA DO AMBIENTE CONSTRUÍDO. UFAL, 2024. http://dx.doi.org/10.46421/entac.v20i1.6279.
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O potencial da terra diatomácea como um resíduo aproveitável, proveniente de processos de filtragem, se dá devido ao seu alto teor de silício e morfologia favorável para reações químicas. Sua granulometria refinada e estrutura amorfa indicam alta reatividade. Deste modo, foi explorada a aplicação deste resíduo como substituto parcial ao cimento Portland, visando obter um material com propriedades mecânicas, boa durabilidade e menores impactos ambientais associados à destinação de resíduos e à emissão de CO2. A dosagem da argamassa foi realizada substituindo o cimento Portland por até 25% de resíduo diatomáceo. Ensaios de resistência à compressão e absorção de água foram realizados nos corpos de prova moldados com o traço estabelecido, comparando seu desempenho com o do cimento Portland puro. O material desenvolvido ficou próximo do limite normativo para cimentos de classe 32, ficando apenas 5% abaixo do exigido. Esse resultado demonstra o enorme potencial da utilização de resíduos na produção de materiais cimentícios sustentáveis, reforçando a viabilidade técnica e a promessa de um futuro mais verde e inovador para a construção civil.
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Vieira, Enayle Soares, Cecília Mariana Gontijo, Emanuel Nicolas Dias Pereira, Lucas Teodoro Vieira Campos, and Douglas Roberto Guimarães Silva. "EFEITOS DE HEMODERIVADOS SINTÉTICOS NO TRATAMENTO DE HEMORRAGIA AGUDA." In Anais do I Congresso Brasileiro de Urgência e Emergência. Even3, 2025. https://doi.org/10.29327/1484146.1-2.
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A perda de sangue do sistema circulatório é, inicialmente, compensada fisiologicamente pelo organismo. Contudo, o prolongamento do quadro de hemorragia aguda pode levar ao choque hemorrágico grave, no qual o comprometimento da função cardíaca associado a arritmias letais culminam em um desfecho fatal de falência de órgãos. O tratamento atual de transfusão com hemoderivados naturais, como concentrado de hemácias (PRBCs), plasma fresco congelado (FFP) e plaquetas, possui a limitação de depender diretamente da disponibilidade nos bancos de sangue, os quais estão linearmente associados à doação de sangue. Por esse motivo, e considerando a necessidade de alternativas promissoras e eficazes, é essencial avaliar as implicações do uso de hemoderivados sintéticos como recursos terapêuticos na hemorragia aguda. Objetivo: Analisar os efeitos do uso de hemoderivados sintéticos no tratamento da hemorragia aguda. Materiais e métodos: Foi realizada uma revisão de literatura na base de dados “PubMed”, utilizando os descritores “Hemorrhage” AND “Blood substitutes” AND “Tissue oxygenation” AND “Hemodynamics”. Os critérios de inclusão consideraram artigos publicados entre 2014 e 2024. Já os critérios de exclusão eliminaram artigos que abordam apenas hemorragia crônica, avaliam exclusivamente transfusões com hemoderivados naturais ou não tratam diretamente do contexto de hemorragia aguda. Dos 342 artigos encontrados, foram selecionados 8 estudos relevantes. Resultados e discussão: Os resultados da revisão mostraram-se favoráveis ao uso de hemoderivados sintéticos no tratamento da hemorragia aguda. Os substitutos sanguíneos testados nos estudos foram: transportadores de oxigênio baseados em hemoglobina (HBOCs), perfluorocarbonetos (PFCs), hemoglobina encapsulada em lipossomas (HbV), hemoglobina de placenta humana polimerizada (PolyPHb), transportador de oxigênio baseado na proteína H-NOX (MOX), hemoglobina porcina polimerizada (pPolyHb) e poli-[hemoglobina-superóxido dismutase-catalase-anidrase carbônica] (PolyHb-SOD-CAT-CA). Graças à aplicação desses produtos artificiais do sangue, foi evidenciada uma recuperação superior e um aumento da taxa de sobrevivência dos modelos simulados de choque hemorrágico. Essa melhora foi associada à preservação da função cardíaca, à prevenção de arritmias letais e à estabilização dos parâmetros hemodinâmicos (como frequência cardíaca e pressão arterial média) e gasométricos (como redução do lactato, aumento da PaO2, redução da PaCO2 e restauração dos níveis de base excess (BE) e bicarbonato (HCO3-)). Também houve uma otimização da oxigenação e da perfusão tecidual, e a remoção dos radicais de oxigênio prejudiciais (por exemplo, o superóxido). Ademais, a infusão com pPolyHb melhorou significativamente a anemia aguda causada pela hemodiluição isovolêmica em ratos experimentais. No entanto, apesar de promissores, algumas pesquisas apresentaram certas limitações dos HBOCs, como toxicidade renal ou hepática e vasoconstrições prejudiciais, mas avanços recentes estão aperfeiçoando sua visão clínica. Já o bioterapêutico OMX, por exemplo, não exibiu efeitos adversos significativos e as evidências indicam que ele pode minimizar o impacto hepático e modular a coagulação, mostrando-se mais seguro. A partir disso, vale ressaltar que as intervenções bem-sucedidas para as hemorragias agudas devem restaurar a função microvascular, melhorando a viscosidade sanguínea e a perfusão capilar. Dessa forma, as próximas gerações de HBOCs e outros hemoderivados sintéticos devem ser ajustados para aumentar a viscosidade e, consequentemente, gerar estresse de cisalhamento suficiente, o que é essencial para promover respostas vasodilatadoras e aprimorar a perfusão tecidual, restaurando o fluxo na microcirculação. Por fim, destaca-se a importância de buscar por alternativas mais seguras, ou seja, que reduzam a toxicidade nos rins e no fígado, e avaliar cuidadosamente a concentração utilizada, já que concentrações mais elevadas de HBOCs demonstraram desfechos mais positivos do que os de concentrações mais baixas. Considerações Finais: O potencial dos hemoderivados como fatores de suporte nos quadros hemorrágicos agudos, aumentando a taxa de sobrevivência e o sucesso da recuperação, é cada vez mais evidente. Entre os fármacos analisados, o H- NOX e a pPolyHB se destacaram pelo bom aproveitamento, demonstrando eficácia no tratamento. Em contrapartida, o HBOC, apesar de útil, apresenta riscos significativos de toxicidade renal e hepática, o que ressalta a necessidade de pesquisa contínua para minimizar seus efeitos adversos. De maneira geral, os hemoderivados sintéticos têm mostrado benefícios substanciais, como a melhoria na oxigenação tecidual, o que os torna uma alternativa viável diante da escassez de sangue nos hemocentros. No entanto, a viabilidade de sua implementação em larga escala dependerá dos avanços nas pesquisas, que precisam otimizar tanto a composição quanto a segurança desses compostos. Portanto, embora o cenário seja promissor, o progresso contínuo da ciência será crucial para consolidar essas alternativas como tratamentos eficazes e seguros no contexto de hemorragias agudas.
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Ahmad, Musheer, Faiyaz Ahmad, Zeba Nasim, Zohra Bano, and Shadab Zafar. "Designing chaos based strong substitution box." In 2015 Eighth International Conference on Contemporary Computing (IC3). IEEE, 2015. http://dx.doi.org/10.1109/ic3.2015.7346660.
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Anuroop, K. B., Anu James, and M. Neema. "Hardware Software Codesign for a Hybrid Substitution Box." In 2017 30th International Conference on VLSI Design and 2017 16th International Conference on Embedded Systems (VLSID). IEEE, 2017. http://dx.doi.org/10.1109/vlsid.2017.46.
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