435 research outputs found

    Searching for efficient cellular automata based keys applied in symmetric key cryptography

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    In this paper we consider a problem of generation by cellular automata of high qualitypseudorandom sequences useful in cryptography. For this purpose one dimensional nonuniformcellular automata is used. The quality of pseudorandom sequences generated by cellular automatadepends on collective behavior of rules assigned to the cellular automata cells. Genetic algorithmis used to find suitable rules from the earlier predefined set of rules. It has been shown that geneticalgorithm eliminates bad subsets of rules and finds subsets of rules, which provide high qualitypseudorandom sequences. These sequences are suitable for symmetric key cryptography and canbe used in different cryptographic modules

    Investigations of cellular automata-based stream ciphers

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    In this thesis paper, we survey the literature arising from Stephan Wolfram\u27s original paper, “Cryptography with Cellular Automata” [WOL86] that first suggested stream ciphers could be constructed with cellular automata. All published research directly and indirectly quoting this paper are summarized up until the present. We also present a novel stream cipher design called Sum4 that is shown to have good randomness properties and resistance to approximation using linear finite shift registers. Sum4 is further studied to determine its effective strength with respect to key size given that an attack with a SAT solver is more efficient than a bruteforce attack. Lastly, we give ideas for further research into improving the Sum4 cipher

    Cellular Automata

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    Modelling and simulation are disciplines of major importance for science and engineering. There is no science without models, and simulation has nowadays become a very useful tool, sometimes unavoidable, for development of both science and engineering. The main attractive feature of cellular automata is that, in spite of their conceptual simplicity which allows an easiness of implementation for computer simulation, as a detailed and complete mathematical analysis in principle, they are able to exhibit a wide variety of amazingly complex behaviour. This feature of cellular automata has attracted the researchers' attention from a wide variety of divergent fields of the exact disciplines of science and engineering, but also of the social sciences, and sometimes beyond. The collective complex behaviour of numerous systems, which emerge from the interaction of a multitude of simple individuals, is being conveniently modelled and simulated with cellular automata for very different purposes. In this book, a number of innovative applications of cellular automata models in the fields of Quantum Computing, Materials Science, Cryptography and Coding, and Robotics and Image Processing are presented

    Artificial Intelligence for the design of symmetric cryptographic primitives

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    Algorithms and the Foundations of Software technolog

    Cellular Automata in Cryptographic Random Generators

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    Cryptographic schemes using one-dimensional, three-neighbor cellular automata as a primitive have been put forth since at least 1985. Early results showed good statistical pseudorandomness, and the simplicity of their construction made them a natural candidate for use in cryptographic applications. Since those early days of cellular automata, research in the field of cryptography has developed a set of tools which allow designers to prove a particular scheme to be as hard as solving an instance of a well-studied problem, suggesting a level of security for the scheme. However, little or no literature is available on whether these cellular automata can be proved secure under even generous assumptions. In fact, much of the literature falls short of providing complete, testable schemes to allow such an analysis. In this thesis, we first examine the suitability of cellular automata as a primitive for building cryptographic primitives. In this report, we focus on pseudorandom bit generation and noninvertibility, the behavioral heart of cryptography. In particular, we focus on cyclic linear and non-linear automata in some of the common configurations to be found in the literature. We examine known attacks against these constructions and, in some cases, improve the results. Finding little evidence of provable security, we then examine whether the desirable properties of cellular automata (i.e. highly parallel, simple construction) can be maintained as the automata are enhanced to provide a foundation for such proofs. This investigation leads us to a new construction of a finite state cellular automaton (FSCA) which is NP-Hard to invert. Finally, we introduce the Chasm pseudorandom generator family built on this construction and provide some initial experimental results using the NIST test suite

    Quantum Computing and Communications

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    This book explains the concepts and basic mathematics of quantum computing and communication. Chapters cover such topics as quantum algorithms, photonic implementations of discrete-time quantum walks, how to build a quantum computer, and quantum key distribution and teleportation, among others

    Multi-operation data encryption mechanism using dynamic data blocking and randomized substitution

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    Existing cryptosystems deal with static design features such as fixed sized data blocks, static substitution and apply identical set of known encryption operations in each encryption round. Fixed sized blocks associate several issues such as ineffective permutations, padding issues, deterministic brute force strength and known-length of bits which support the cracker in formulating of modern cryptanalysis. Existing static substitution policies are either not optimally fit for dynamic sized data blocks or contain known S-box transformation and fixed lookup tables. Moreover, static substitution does not directly correlate with secret key due to which it has not been shown safer especially for Advanced Encryption Standard (AES) and Data Encryption Standard (DES). Presently, entire cryptosystems encrypt each data block with identical set of known operations in each iteration, thereby lacked to offer dynamic selection of encryption operation. These discussed, static design features are fully known to the cracker, therefore caused the practical cracking of DES and undesirable security pitfalls against AES as witnessed in earlier studies. Various studies have reported the mathematical cryptanalysis of AES up to full of its 14 rounds. Thus, this situation completely demands the proposal of dynamic design features in symmetric cryptosystems. Firstly, as a substitute to fixed sized data blocks, the Dynamic Data Blocking Mechanism (DDBM) has been proposed to provide the facility of dynamic sized data blocks. Secondly, as an alternative of static substitution approach, a Randomized Substitution Mechanism (RSM) has been proposed which can randomly modify session-keys and plaintext blocks. Finally, Multi-operation Data Encryption Mechanism (MoDEM) has been proposed to tackle the issue of static and identical set of known encryption operations on each data block in each round. With MoDEM, the encryption operation can dynamically be selected against the desired data block from the list of multiple operations bundled with several sub-operations. The methods or operations such as exclusive-OR, 8-bit permutation, random substitution, cyclic-shift and logical operations are used. Results show that DDBM can provide dynamic sized data blocks comparatively to existing approaches. Both RSM and MoDEM fulfill dynamicity and randomness properties as tested and validated under recommended statistical analysis with standard tool. The proposed method not only contains randomness and avalanche properties but it also has passed recommended statistical tests within five encryption rounds (significant than existing). Moreover, mathematical testing shows that common security attacks are not applicable on MoDEM and brute force attack is significantly resistive

    Cryptographic primitives on reconfigurable platforms.

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    Tsoi Kuen Hung.Thesis (M.Phil.)--Chinese University of Hong Kong, 2002.Includes bibliographical references (leaves 84-92).Abstracts in English and Chinese.Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Motivation --- p.1Chapter 1.2 --- Objectives --- p.3Chapter 1.3 --- Contributions --- p.3Chapter 1.4 --- Thesis Organization --- p.4Chapter 2 --- Background and Review --- p.6Chapter 2.1 --- Introduction --- p.6Chapter 2.2 --- Cryptographic Algorithms --- p.6Chapter 2.3 --- Cryptographic Applications --- p.10Chapter 2.4 --- Modern Reconfigurable Platforms --- p.11Chapter 2.5 --- Review of Related Work --- p.14Chapter 2.5.1 --- Montgomery Multiplier --- p.14Chapter 2.5.2 --- IDEA Cipher --- p.16Chapter 2.5.3 --- RC4 Key Search --- p.17Chapter 2.5.4 --- Secure Random Number Generator --- p.18Chapter 2.6 --- Summary --- p.19Chapter 3 --- The IDEA Cipher --- p.20Chapter 3.1 --- Introduction --- p.20Chapter 3.2 --- The IDEA Algorithm --- p.21Chapter 3.2.1 --- Cipher Data Path --- p.21Chapter 3.2.2 --- S-Box: Multiplication Modulo 216 + 1 --- p.23Chapter 3.2.3 --- Key Schedule --- p.24Chapter 3.3 --- FPGA-based IDEA Implementation --- p.24Chapter 3.3.1 --- Multiplication Modulo 216 + 1 --- p.24Chapter 3.3.2 --- Deeply Pipelined IDEA Core --- p.26Chapter 3.3.3 --- Area Saving Modification --- p.28Chapter 3.3.4 --- Key Block in Memory --- p.28Chapter 3.3.5 --- Pipelined Key Block --- p.30Chapter 3.3.6 --- Interface --- p.31Chapter 3.3.7 --- Pipelined Design in CBC Mode --- p.31Chapter 3.4 --- Summary --- p.32Chapter 4 --- Variable Radix Montgomery Multiplier --- p.33Chapter 4.1 --- Introduction --- p.33Chapter 4.2 --- RSA Algorithm --- p.34Chapter 4.3 --- Montgomery Algorithm - Ax B mod N --- p.35Chapter 4.4 --- Systolic Array Structure --- p.36Chapter 4.5 --- Radix-2k Core --- p.37Chapter 4.5.1 --- The Original Kornerup Method (Bit-Serial) --- p.37Chapter 4.5.2 --- The Radix-2k Method --- p.38Chapter 4.5.3 --- Time-Space Relationship of Systolic Cells --- p.38Chapter 4.5.4 --- Design Correctness --- p.40Chapter 4.6 --- Implementation Details --- p.40Chapter 4.7 --- Summary --- p.41Chapter 5 --- Parallel RC4 Engine --- p.42Chapter 5.1 --- Introduction --- p.42Chapter 5.2 --- Algorithms --- p.44Chapter 5.2.1 --- RC4 --- p.44Chapter 5.2.2 --- Key Search --- p.46Chapter 5.3 --- System Architecture --- p.47Chapter 5.3.1 --- RC4 Cell Design --- p.47Chapter 5.3.2 --- Key Search --- p.49Chapter 5.3.3 --- Interface --- p.50Chapter 5.4 --- Implementation --- p.50Chapter 5.4.1 --- RC4 cell --- p.51Chapter 5.4.2 --- Floorplan --- p.53Chapter 5.5 --- Summary --- p.53Chapter 6 --- Blum Blum Shub Random Number Generator --- p.55Chapter 6.1 --- Introduction --- p.55Chapter 6.2 --- RRNG Algorithm . . --- p.56Chapter 6.3 --- PRNG Algorithm --- p.58Chapter 6.4 --- Architectural Overview --- p.59Chapter 6.5 --- Implementation --- p.59Chapter 6.5.1 --- Hardware RRNG --- p.60Chapter 6.5.2 --- BBS PRNG --- p.61Chapter 6.5.3 --- Interface --- p.66Chapter 6.6 --- Summary --- p.66Chapter 7 --- Experimental Results --- p.68Chapter 7.1 --- Design Platform --- p.68Chapter 7.2 --- IDEA Cipher --- p.69Chapter 7.2.1 --- Size of IDEA Cipher --- p.70Chapter 7.2.2 --- Performance of IDEA Cipher --- p.70Chapter 7.3 --- Variable Radix Systolic Array --- p.71Chapter 7.4 --- Parallel RC4 Engine --- p.75Chapter 7.5 --- BBS Random Number Generator --- p.76Chapter 7.5.1 --- Size --- p.76Chapter 7.5.2 --- Speed --- p.76Chapter 7.5.3 --- External Clock --- p.77Chapter 7.5.4 --- Random Performance --- p.78Chapter 7.6 --- Summary --- p.78Chapter 8 --- Conclusion --- p.81Chapter 8.1 --- Future Development --- p.83Bibliography --- p.8
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