Papers by Guillermo Sosa Gómez
Debilidad SAC en el algoritmo de cifrado en flujo RC4 - SAC Weakness in RC4 stream cipher
ReCIBE, Revista electrónica de Computación, Informática, Biomédica y Electrónica, May 2, 2017
En este trabajo se describe una interesante via para la deteccion de la existencia de entradas de... more En este trabajo se describe una interesante via para la deteccion de la existencia de entradas de colision en el algoritmo de cifrado en flujo RC4 basado en el criterio estricto de avalancha y se discuten los resultados obtenidos en comparacion con las debilidades y ataques reportados sobre el RC4 que plantean la existencia de una fuerte correlacion entre los parametros de entrada y salida del algoritmo. Abstract: This paper describes an interesting way for the detection of the colliding entries existence in the RC4 stream cipher algorithm based in the strict avalanche criterion and the results obtained are discussed in comparison with the reported weaknesses and attacks on the RC4 that raise the existence of a strong correlation between the parameters of Input and output of the algorithm. Keywords: strict avalanche criterion, colliding entries, statistical correlation, RC4.
Resumen: En este trabajo se describe una interesante vía para la detección de la existencia de en... more Resumen: En este trabajo se describe una interesante vía para la detección de la existencia de entradas de colisión en el algoritmo de cifrado en flujo RC4 basado en el criterio estricto de avalancha y se discuten los resultados obtenidos en comparación con las debilidades y ataques reportados sobre el RC4 que plantean la existencia de una fuerte correlación entre los parámetros de entrada y salida del algoritmo.
Security and Communication Networks
PassPoint is a graphical authentication technique that is based on the selection of five points i... more PassPoint is a graphical authentication technique that is based on the selection of five points in an image. A detected vulnerability lies in the possible existence of a pattern in the points that make up the password. The objective of this work is to detect nonrandom graphical passwords in the PassPoint scenario. A spatial randomness test based on the average of Delaunay triangles’ perimeter is proposed, given the ineffectiveness of the classic tests in this scenario, which only consists of five points. A state-of-the-art of various applications of Voronoi polygons and Delaunay triangulations are presented to detect clustered and regular patterns. The distributions of the averages of the triangles’ perimeters in the PassPoint scenario for various sizes of images are disclosed, which were unknown. The test’s decision criterion was constructed from one of the best distributions to which the data were adjusted. Type I and type II errors were estimated, and it was concluded that the pr...
Entropy
There are many algorithms used with different purposes in the area of cryptography. Amongst these... more There are many algorithms used with different purposes in the area of cryptography. Amongst these, Genetic Algorithms have been used, particularly in the cryptanalysis of block ciphers. Interest in the use of and research on such algorithms has increased lately, with a special focus on the analysis and improvement of the properties and characteristics of these algorithms. In this way, the present work focuses on studying the fitness functions involved in Genetic Algorithms. First, a methodology was proposed to verify that the closeness to 1 of some fitness functions’ values that use decimal distance implies decimal closeness to the key. On the other hand, the foundation of a theory is developed in order to characterize such fitness functions and determine, a priori, if one method is more effective than another in the attack to block ciphers using Genetic Algorithms.
IEEE Access, 2022
Many research focuses on finding S-boxes with good cryptographic properties applying a heuristic ... more Many research focuses on finding S-boxes with good cryptographic properties applying a heuristic method and a balanced, objective function. The design of S-boxes with theoretical resistance against Side-Channel Attacks by power consumption is addressed with properties defined under one of these two models: the Hamming Distance leakage model and the Hamming Weight leakage model. As far as we know, a balanced search criterion that considers properties under both, at the same time, remains an open problem. We define two new optimal objective functions that can be used to obtain S-boxes with good cryptographic properties values, keeping high theoretical resistance for the two leakage models; we encourage using at least one of our objective functions. We apply a Hill Climbing heuristic method over the S-box's space to measure which objective function is better and to compare the obtained S-boxes with the S-boxes in the actual literature. We also confirm some key relationships between the properties and which property is more suitable to be used. INDEX TERMS S-box, hamming leakage model, transparency order, cryptography, power attack.
Computational Intelligence and Neuroscience
Combinatorial optimization problems allow for modeling multiple situations in which proper alloca... more Combinatorial optimization problems allow for modeling multiple situations in which proper allocation of resources is needed. For some real-world problems, the use of fuzzy elements in the models allows for incorporating certain levels of uncertainty to better approximate such real-world situations. One way to solve combinatorial optimization problems with fuzzy elements is the parametric approach, where it is necessary to define how to explore different relaxation levels using alpha-cuts. Researchers tend to select such alpha-cuts uniformly. The current investigation proposes a novel strategy for selecting alpha-cuts in the School Bus Routing Problem with fuzzy students’ maximum walking distance. This proposal bases its foundations on the number of student-bus stop pairs available according to the different levels of relaxations allowed. Results demonstrate how the proposed strategy gives attractive solutions with more diverse trade-offs, contrasted with other methods in the litera...
Journal of Information Security and Applications
The study of S-box properties relations is an interesting problem. In this work we develop and ap... more The study of S-box properties relations is an interesting problem. In this work we develop and apply a local search method to create trajectories over S-box space. These trajectories shows the existence of an strong linear correlation between confusion coefficient variance, Transparency Order, Modified Transparency Order and Revised Transparency Order, under the Hamming Weight model. When the values of Confusion Coefficient Variance increases then the values of Transparency Order, the values of Modified Transparency Order beta zero, and the values of Revised Transparency Order beta zero, decreases, reflecting the same theoretical resistance against to Side-Channel Attacks by power consumption. As far as we know, it is the first time that Local Search trajectories are used to discover relations between cryptography properties.
Heliyon
Several real-life optimization problems, such as the case of several instances of the School Bus ... more Several real-life optimization problems, such as the case of several instances of the School Bus Routing Problem (SBRP), are very complex and expensive to solve with exact algorithms. Metaheuristics are a good alternative in these situations because they are capable of generating good quality solutions to these problems in a reasonable time. Metaheuristics iterate thousands of times by introducing changes concerning the previous solutions. Each new solution must be evaluated, and sometimes, the new solutions have elements unchanged that are unnecessarily re-evaluated. However, an approach avoids repeatedly evaluating parts of different solutions known as partial evaluation. This work applies this technique to the SBRP to reduce its execution time. To apply the partial evaluation approach in this problem, each solution contains the information of the change that was made concerning the solution from which it originates. With this information, when evaluating the objective function, it will be only necessary to analyze the routes that changed. In the literature reviewed, no previous work was found in which the partial evaluation approach has been applied in the context of SBRP. In this paper we apply it in order to reduce the computational cost of SBRP solutions based on metaheuristics. The results show that it is possible to decrease the execution time in 80% of the instances, reducing the execution time on average by 73.6%.
Inf., 2021
During the search for S-boxes resistant to Power Attacks, the S-box space has recently been divid... more During the search for S-boxes resistant to Power Attacks, the S-box space has recently been divided into Hamming Weight classes, according to its theoretical resistance to these attacks using the metric variance of the confusion coefficient. This partition allows for reducing the size of the search space. The swap operator is frequently used when searching with a random selection of items to be exchanged. In this work, the theoretical probability of changing Hamming Weight class of the S-box is calculated when the swap operator is applied randomly in a permutation. The precision of these probabilities is confirmed experimentally. Its limit and a recursive formula are theoretically proved. It is shown that this operator changes classes with high probability, which favors the exploration of the Hamming Weight class of S-boxes space but dramatically reduces the exploitation within classes. These results are generalized, showing that the probability of moving within the same class is su...
Mathematics, 2022
In 2005, Guillot published a method for the construction of Boolean functions using linear codes ... more In 2005, Guillot published a method for the construction of Boolean functions using linear codes through the Maiorana–McFarland construction of Boolean functions. In this work, we present a construction using Hermitian codes, starting from the classic Maiorana–McFarland construction. This new construction describes how the set of variables is divided into two complementary subspaces, one of these subspaces being a Hermitian Code. The ideal theoretical parameters of the Hermitian code are proposed to reach desirable values of the cryptographic properties of the constructed Boolean functions such as nonlinearity, resiliency order, and order of propagation. An extension of Guillot’s work is also made regarding parameters selection using algebraic geometric tools, including explicit examples.
Applied Sciences, 2022
Conventional electronic voting systems use a centralized scheme. A central administration of thes... more Conventional electronic voting systems use a centralized scheme. A central administration of these systems manages the entire voting process and has partial or total control over the database and the system itself. This creates some problems, accidental or intentional, such as possible manipulation of the database and double voting. Many of these problems have been solved thanks to permissionless blockchain technologies in new voting systems; however, the classic consensus method of such blockchains requires specific computing power during each voting operation. This has a significant impact on power consumption, compromises the efficiency and increases the system latency. However, using a permissioned blockchain improves efficiency and reduces system energy consumption, mainly due to the elimination of the typical consensus protocols used by public blockchains. The use of smart contracts provides a secure mechanism to guarantee the accuracy of the voting result and make the countin...
Improvements in the computing efficiency of the probabilities of the LIL test for the PRNG evaluation
Theoretical Computer Science, 2021
Automating the avocado supply chain with blockchain and off-chain
JOURNAL OF ADVANCES IN MATHEMATICS, 2016
In this work we will solve the problem of expression of the sum of two given elements of a finite... more In this work we will solve the problem of expression of the sum of two given elements of a finite field, as power of the primitive element of the field. We obtain a reduced table of the Zech's logarithm from our proposal that relate the Zech'slogarithm with the partition of the exponents of the powers of elements over finite field ð‘®ð‘(ð’‘ð’) in p-cyclotomic cosets modulo (ð’‘ð’−ðŸ). This reduces, in a significant way, the quantity of information to store and it facilitates its use in several cryptographic algorithms, specifically in asimetric cryptography. It is illustrated the computationof the Zech'slogarithm of any element thatdoesn't appear in the obtained reduced table.
Evaluation of input — output statistical dependence PRNGs by SAC
2016 International Conference on Software Process Improvement (CIMPS), 2016
The strict avalanche criterion (SAC) is one of the desirable properties in the functions to be us... more The strict avalanche criterion (SAC) is one of the desirable properties in the functions to be used for cryptographic purposes. This paper presents an application of this to evaluate the present diffusion algorithms pseudo-random number generation (PRNGs). So, to measure the statistical independence of the outputs towards the input parameters.
Sensors, 2022
An alternative authentication method to traditional alphanumeric passwords is graphical password ... more An alternative authentication method to traditional alphanumeric passwords is graphical password authentication, also known as graphical authentication, for which one of the most valuable cued-recall techniques is PassPoints. This technique stands out for its security and usability. However, it can be violated if the user follows a predefined pattern when selecting the five points in an image as their passwords, such as the DIAG and LINE patterns. Dictionary attacks can be built using these two patterns to compromise graphical passwords. So far, no reports have been found in the state of the art about any test capable of detecting graphical passwords with DIAG or LINE patterns in PassPoints. Studies carried out in other scenarios have shown the effectiveness of the characteristics of Delaunay triangulations in extracting information about the dependence between the points. In this work, graphical passwords formed by five randomly selected points on an image are compared with passwor...
An Heuristic Algorithm to Calculate the Minimum Amount of Anesthesia Using MRI
Axioms, 2019
In 2005, Philippe Guillot presented a new construction of Boolean functions using linear codes as... more In 2005, Philippe Guillot presented a new construction of Boolean functions using linear codes as an extension of the Maiorana–McFarland’s (MM) construction of bent functions. In this paper, we study a new family of Boolean functions with cryptographically strong properties, such as non-linearity, propagation criterion, resiliency, and balance. The construction of cryptographically strong Boolean functions is a daunting task, and there is currently a wide range of algebraic techniques and heuristics for constructing such functions; however, these methods can be complex, computationally difficult to implement, and not always produce a sufficient variety of functions. We present in this paper a construction of Boolean functions using algebraic codes following Guillot’s work.
Algoritmos para la determinación de los homomorfismos de inmersión de Campos de Galois
Los homomorfismos entre estructuras algebraicas son de mucha utilidad tanto en la matematica, como... more Los homomorfismos entre estructuras algebraicas son de mucha utilidad tanto en la matematica, como en la ciencia de la computacion. En particular, los homorfismos entre campos de Galois son utilizados en la criptografia, en los llamados esquemas de cifrado homomorfico Zhang and Yue (2013), y en la teoria de codigos, por ejemplo, en la denominada decodificacion local Grigorescu et˜al. (2006). Por lo que puede ser necesario conocer cuales son las funciones que constituyen homomorfismos entre campos de Galois. En este trabajo se propone un algoritmo para la determinacion de los homomorfismos de inmersion que existen entre los campos GF(pn) y GF(pm) cuando n | m.
Test for Detection of Weak Graphic Passwords in Passpoint Based on the Mean Distance between Points
Symmetry, 2021
This work demonstrates the ineffectiveness of the Ripley’s K function tests, the distance to the ... more This work demonstrates the ineffectiveness of the Ripley’s K function tests, the distance to the nearest neighbor, and the empty space function in the Graphical Authentication scenario with Passpoint for the detection of non-random graphical passwords. The results obtained show that none of these tests effectively detect non-random graphical passwords; the reason for their failure is attributed to the small sample of the spatial pattern in question, where only the five points of the graphical password are analyzed. Consequently, a test based on mean distances is proposed, whose experiments show that it detects with good efficiency non-random graphical passwords in Passpoint. The test was designed to be included in the Graphical Authentication systems with Passpoint to warn the user about a possibly weak password during the registration phase, and in this way, the security of the system is increased.
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Papers by Guillermo Sosa Gómez