Yazar "Sakalli, M. Tolga" seçeneğine göre listele

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    Affine equivalence in S-boxes
    (IEEE, 2006) Sakalli, M. Tolga; Bulus, Ercan; Sahin, Andac; Buyuksaracogcu, Fatma
    Nowadays, Linear redundancy has been identified in all S-boxes generated from finite field inversion and power mappings. That means it may be used in a new cryptanalytic attack in the future. In our study, we have developed an application to show that all output functions of an S-box are equivalent under an affine transformation of the input bits. To realize this application, we have used 4-bit input and 4-bit output S-box which has similar design technique with AES S-box. This application shows that S-boxes generated with the same tecnique of AES S-box has a vulnerability.
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    Classifying 8-bit to 8-bit S-boxes based on power mappings from the point of DDT and LAT distributions
    (Springer-Verlag Berlin, 2008) Aslan, Bora; Sakalli, M. Tolga; Bulus, Ercan
    S-boxes are vital elements in the design of symmetric ciphers. To date, the techniques for the construction of S-boxes have included pseudo-random generation, finite field inversion, power mappings and heuristic techniques. From these techniques, the use of finite field inversion in the construction of an S-box is so popular because it presents good cryptographic properties. On the other hand, while S-boxes such as AES, Shark, Square and Hierocrypt that are based on inversion mapping over GF(2(n)) use an affine transformation after the output of the S-box, in some ciphers like Camellia, an additional affine transformation is used before the input. In this paper, we classify 8-bit to 8-bit S-boxes based on power mappings into classes according to DDT and LAT distributions. Moreover, a formula is given for the calculation of the number of terms in the algebraic expression for a power mapping based S-box according to the given three probable cases.
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    Energy Consumption Analysis of Lightweight Cryptographic Algorithms That Can Be Used in the Security of Internet of Things Applications
    (Wiley-Hindawi, 2020) Aslan, Bora; Yavuzer Aslan, Fusun; Sakalli, M. Tolga
    The Internet of Things (IoT) has begun to acquire place in our lives quietly and gradually thanks to the presence of wireless communication systems. An increasing number of M2M applications, such as smart meters, healthcare monitoring, transportation and packaging, or asset tracking, make a significant contribution to the growth of devices and connections. Within such a large and uncontrollable ecosystem, IoT poses several new problems. Security and privacy are among the most important of these problems. Lightweight cryptography can be used more effectively for small size, low energy, and small footprint such as RFID tags, sensors, and contactless smart cards. Therefore, it can be used to ensure security and privacy in the IoT applications. In this study, PRESENT, CLEFIA, PICCOLO, PRINCE, and LBLOCK lightweight cryptographic algorithms, which can be used to secure data in IoT applications, were analyzed in a test environment. As a result of the tests, the energy consumption of the algorithms, current measurement, active mode working time, and active mode energy consumption were identified and based on this, some inferences have been made.
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    Obtaining algebraic expression of an S-box based on inversion mapping using finite field theory
    (IEEE, 2007) Sakalli, M. Tolga; Bulus, Ercan; Sahin, Andac; Bueyueksaracoglu, Fatma
    Recently proposed block ciphers like AES, Square, Shark use S-boxes that are based on inversion mapping over a finite field F=GF(p(n)). Because of the simple algebraic structure of S-boxes generated in this way, these ciphers usually use a bitwise affine transformation after the inversion mapping. In this study, we show how we obtain algebraic expression of an S-box based on inversion mapping using finite field theory and trace function combined with theoretical preliminaries related with this theory.
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    On the Algebraic Expression of the AES S-Box Like S-Boxes
    (Springer-Verlag Berlin, 2010) Sakalli, M. Tolga; Aslan, Bora; Bulus, Ercan; Mesut, Andac Sahin; Buyuksaracoglu, Fatma; Karaahmetoglu, Osman
    In the literature, there are several proposed block ciphers like ADS, Square, Shark and Hierocrypt which use S-boxes that are based on inversion mapping over a finite field. Because of the simple algebraic structure of S-boxes generated in this way, these ciphers usually use a bitwise affine transformation after the inversion mapping. In some ciphers like Camellia, an additional affine transformation is used before the input of the S-box as well. In this paper, we study algebraic expressions of S-boxes based on power mappings with the aid of finite field theory and show that the number of terms in the algebraic expression of an S-box based on power mappings changes according to the place an affine transformation is added. Moreover, a new method is presented to resolve the algebraic expression of the AES S-box like S-boxes according to the given three probable cases.
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    On the Design Strategies of Diffusion Layers and Key Schedule in Lightweight Block Ciphers
    (IEEE, 2017) Pehlivanoglu, Meltem Kurt; Akleylek, Sedat; Sakalli, M. Tolga; Duru, Nevcihan
    In recent years, lightweight cryptography has become essential especially for the resource-constrained devices to ensure data protection and security. The selection of suitable cryptographic algorithm which is directly linked to requirements of the system will have dynamically effect on following such metrics like performance of the device, hardware resource cost, the area, speed, efficiency, computation latency, communication bandwidth. This paper aims to provide a comprehensive survey on the lightweight block ciphers that were given in the literature and throw a light on the future research directions. Then, the focus is given to the diffusion layers in view of construction methods and efficiency. A new metric based on the order of the matrix to measure the security of diffusion layer consisting MDS matrix over a finite field extension is proposed and related experimental results are given. Key schedule of the lightweight block ciphers is analyzed.