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Side channels
Kolařík, Jan ; Sobotka, Jiří (referee) ; Martinásek, Zdeněk (advisor)
This Master Thesis deals with the side channels, AES encryption algorithm and the use of neural networks to obtain the encryption key. The first part of this work is focused on the basics of cryptography and attacks on cryptographic module. The second part is focused on electromagnetic side channel attack on PIC16F84A microcontroller with embedded AES algorithm. In this section, the Master Thesis tries to analyze electromagnetic emissions of operation S-Box in AES algorithm and try to find sensitive information to use neural network identify encryption key of the AES algorithm. In conclusion is described the software source code to determine the encryption key, summarized results and discussed ways to defend against electromagnetic side channel attack.
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Design of S-Boxes Using Genetic Algorithms
Hovorka, Bedřich ; Zadina, Martin (referee) ; Hanáček, Petr (advisor)
This work deals with part of the encryption algorithm, called S-box and its development. For its development is used evolutionary computing, such as classical genetic algorithm, Estimation of Distribution Algorithm, Cartesian genetic programming and multi-criteria VEGA and SPEA algorithms. This thesis aims to test the properties of substitution boxes to its evolutionary development. Firstly, the work deals with cryptography and issues of s-boxes. There are explained basic concepts and describes the selected criteria of safety. Next chapter explains evolutionary algorithms and multi-criteria optimization. This knowledge is used to design and program implementation, which are described below. Finally discusses the application of the criteria studied. Discussed here is searching S-boxes in both single-criteria, and especially in multi-criteria genetic search.
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Constructions of APN permutations
Krasnayová, Dáša ; Göloglu, Faruk (advisor) ; Lisoněk, Petr (referee)
In this thesis, we examine a family of vectorial boolean functions on F22m inspired by Kim function, in order to find new APN permutations on F22m for m > 2. The functions of this family are defined as F(X) = X3 + bX3q + cX2q+1 + dXq+2 , where parameters b, c and d are from F2m . Necessary and sufficient conditions for this functions to be APN or equivalent to a permutation are presented in this thesis. To find conditions for being APN, Trace-0/Trace-1 decomposition method is used. A method using exponential sums is used to deduce which functions of this family is CCZ-equivalent to a certain type of permutation. These results were then used to search for APN permutations on F26 and F210 . 1
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Algebraická teorie S-boxů
Ďuránová, Elena ; Tůma, Jiří (advisor) ; Drápal, Aleš (referee)
The thesis focuses on an algebraic description of S-boxes by the special type of quadratic equations, defined as biaffine equations. Biaffine equations satisfying S-boxes of higher order may not even exist. However, the special type of S-boxes en- ables to find such equations also for S-boxes of higher order. The S-box in the block cipher Rijndael, composed of the inverse function and the affine transformation, is an example of such special type of S-boxes. The thesis proves that a number of biaffine equations satisfying an S-box of this type does not depend on the affine function. The thesis also proves that for every S-box of order n formed by the in- verse function there exist at least 3n − 1 biaffine equations satisfying this S-box. 1
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Design of S-Boxes Using Genetic Algorithms
Hovorka, Bedřich ; Zadina, Martin (referee) ; Hanáček, Petr (advisor)
This work deals with part of the encryption algorithm, called S-box and its development. For its development is used evolutionary computing, such as classical genetic algorithm, Estimation of Distribution Algorithm, Cartesian genetic programming and multi-criteria VEGA and SPEA algorithms. This thesis aims to test the properties of substitution boxes to its evolutionary development. Firstly, the work deals with cryptography and issues of s-boxes. There are explained basic concepts and describes the selected criteria of safety. Next chapter explains evolutionary algorithms and multi-criteria optimization. This knowledge is used to design and program implementation, which are described below. Finally discusses the application of the criteria studied. Discussed here is searching S-boxes in both single-criteria, and especially in multi-criteria genetic search.
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Side channels
Kolařík, Jan ; Sobotka, Jiří (referee) ; Martinásek, Zdeněk (advisor)
This Master Thesis deals with the side channels, AES encryption algorithm and the use of neural networks to obtain the encryption key. The first part of this work is focused on the basics of cryptography and attacks on cryptographic module. The second part is focused on electromagnetic side channel attack on PIC16F84A microcontroller with embedded AES algorithm. In this section, the Master Thesis tries to analyze electromagnetic emissions of operation S-Box in AES algorithm and try to find sensitive information to use neural network identify encryption key of the AES algorithm. In conclusion is described the software source code to determine the encryption key, summarized results and discussed ways to defend against electromagnetic side channel attack.
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