Showing papers on "Differential cryptanalysis published in 2015"
29 Nov 2015
TL;DR: This paper presents the block cipher Midorii¾?, the Japanese translation for the word Green, that is optimized with respect to the energy consumed by the circuit per bt in encryption or decryption operation, and proposes two energy-efficient block ciphers Midori128i½?and Midori64i¼?
Abstract: In the past few years, lightweight cryptography has become a popular research discipline with a number of ciphers and hash functions proposed. The designers' focus has been predominantly to minimize the hardware area, while other goals such as low latency have been addressed rather recently only. However, the optimization goal of low energy for block cipher design has not been explicitly addressed so far. At the same time, it is a crucial measure of goodness for an algorithm. Indeed, a cipher optimized with respect to energy has wide applications, especially in constrained environments running on a tight power/energy budget such as medical implants.
This paper presents the block cipher Midorii¾?The name of the cipher is the Japanese translation for the word Green. that is optimized with respect to the energy consumed by the circuit per bt in encryption or decryption operation. We deliberate on the design choices that lead to low energy consumption in an electrical circuit, and try to optimize each component of the circuit as well as its entire architecture for energy. An added motivation is to make both encryption and decryption functionalities available by small tweak in the circuit that would not incur significant area or energy overheads. We propose two energy-efficient block ciphers Midori128i¾?and Midori64i¾?with block sizes equal to 128 and 64 bits respectively. These ciphers have the added property that a circuit that provides both the functionalities of encryption and decryption can be designed with very little overhead in terms of area and energy. We compare our results with other ciphers with similar characteristics: it was found that the energy consumptions ofi¾?Midori64i¾? and Midori128i¾? are by far better when compared ciphers like PRINCE and NOEKEON.
502 citations
16 Aug 2015
TL;DR: In this paper, efficiently computable and easily implementable expressions for the exact differential and linear behaviour of Simon-like round functions are derived.
Abstract: In this paper we analyse the general class of functions underlying the Simon block cipher In particular, we derive efficiently computable and easily implementable expressions for the exact differential and linear behaviour of Simon-like round functions
207 citations
TL;DR: This work examines more closely the security of symmetric ciphers against quantum attacks, and investigates quantum versions of differential and linear cryptanalysis techniques, showing that it is usually possible to use quantum computations to obtain a quadratic speed-up for these attack techniques, but the situation must be nuanced.
Abstract: Quantum computers, that may become available one day, would impact many scientific fields, most notably cryptography since many asymmetric primitives are insecure against an adversary with quantum capabilities. Cryptographers are already anticipating this threat by proposing and studying a number of potentially quantum-safe alternatives for those primitives. On the other hand, symmetric primitives seem less vulnerable against quantum computing: the main known applicable result is Grover's algorithm that gives a quadratic speed-up for exhaustive search.
In this work, we examine more closely the security of symmetric ciphers against quantum attacks. Since our trust in symmetric ciphers relies mostly on their ability to resist cryptanalysis techniques, we investigate quantum cryptanalysis techniques. More specifically, we consider quantum versions of differential and linear cryptanalysis. We show that it is usually possible to use quantum computations to obtain a quadratic speed-up for these attack techniques, but the situation must be nuanced: we don't get a quadratic speed-up for all variants of the attacks. This allows us to demonstrate the following non-intuitive result: the best attack in the classical world does not necessarily lead to the best quantum one. We give some examples of application on ciphers LAC and KLEIN. We also discuss the important difference between an adversary that can only perform quantum computations, and an adversary that can also make quantum queries to a keyed primitive.
86 citations
12 Aug 2015
TL;DR: The energy consumption model of a CMOS gate is studied and it is concluded that the energy consumed per cycle during the encryption operation of an r-round unrolled architecture of any block cipher is a quadratic function in r.
Abstract: In the last few years, the field of lightweight cryptography has seen an influx in the number of block ciphers and hash functions being proposed. One of the metrics that define a good lightweight design is the energy consumed per unit operation of the algorithm. For block ciphers, this operation is the encryption of one plaintext. By studying the energy consumption model of a CMOS gate, we arrive at the conclusion that the energy consumed per cycle during the encryption operation of an r-round unrolled architecture of any block cipher is a quadratic function in r. We then apply our model to 9 well known lightweight block ciphers, and thereby try to predict the optimal value of r at which an r-round unrolled architecture for a cipher is likely to be most energy efficient. We also try to relate our results to some physical design parameters like the signal delay across a round and algorithmic parameters like the number of rounds taken to achieve full diffusion of a difference in the plaintext/key.
84 citations
TL;DR: This paper surveys some of the theoretical results obtained on PN and APN functions in the last 25 years and discusses examples of ciphers and their resistance to differential attacks.
79 citations
29 Nov 2015
TL;DR: In this paper, the authors examined the collision resistance of step-reduced versions of SHA-512/224 and SHA512/256 by using differential cryptanalysis in combination with sophisticated search tools and showed that the truncation performed by these variants on their larger state allows them to attack several more rounds compared to the untruncated family members.
Abstract: In 2012, NIST standardized SHA-512/224 and SHA-512/256, two truncated variants of SHA-512, in FIPS 180-4. These two hash functions are faster than SHA-224 and SHA-256 on 64-bit platforms, while maintaining the same hash size and claimed security level. So far, no third-party analysis of SHA-512/224 or SHA-512/256 has been published. In this work, we examine the collision resistance of step-reduced versions of SHA-512/224 and SHA-512/256 by using differential cryptanalysis in combination with sophisticated search tools. We are able to generate practical examples of free-start collisions for 44-step SHA-512/224 and 43-step SHA-512/256. Thus, the truncation performed by these variants on their larger state allows us to attack several more rounds compared to the untruncated family members. In addition, we improve upon the best published collisions for 24-step SHA-512 and present practical collisions for 27 steps of SHA-512/224, SHA-512/256, and SHA-512.
71 citations
TL;DR: New distinguishers on PRINCE-like ciphers are introduced by constructing probable or impossible relations from the cipher data located at layers that are symmetric around the middle of the cipher, called reflection characteristics in this paper, depend crucially on the choice of the reflection parameter α.
Abstract: PRINCE is a low-latency block cipher presented at ASIACRYPT 2012. The cipher was designed with a property called ?-reflection which reduces the definition of decryption with a given key to encryption with a different but related key determined by ?. In the design document, it was shown that PRINCE is secure against known attacks independently of the value of ?, and the design criteria for ? remained open.
In this paper, we introduce new distinguishers on PRINCE-like ciphers by constructing probable or impossible relations from the cipher data located at layers that are symmetric around the middle of the cipher. We show that the probabilities of such relations, called reflection characteristics in this paper, depend crucially on the choice of the reflection parameter ?. Several classes of ? are investigated. As a result we show that there exist values of ? which, if used in the otherwise original PRINCE, would allow a key-recovery attack on the full 12-round cipher with the data complexity of 257.98 known plaintexts and the time complexity of 272.39 encryptions. While this attack is not better than the generic attack on the complete cipher, where the core cipher is protected by the whitening key, the same reflection distinguisher, when applied on the core cipher without the whitening key, yields a key-recovery attack with time complexity less than exhaustive key search and data complexity of 256.21 known plaintexts. As a result of the new cryptanalysis method presented in this paper, new design criteria concerning the selection of the value of ? for PRINCE-like ciphers are obtained.
55 citations
TL;DR: The theoretical analysis and simulation results indicate that the encryption scheme is insecure and a novel analysis method called double differential cryptanalysis comparison (DDCC) is proposed that is valid to break multi-round encryption with 16N(2)+1 chosen plain-images, where N(2) is the size of the image.
48 citations
TL;DR: A new simple algorithm to generate key-dependent S- boxes and inverse S-boxes for block cipher systems with good performance and can be applied to AES is presented.
Abstract: A nonlinear substitution operation of bytes is the main strength factor of the Advanced Encryption Standard (AES) and other modern cipher systems. In this paper we have presented a new simple algorithm to generate key-dependent S-boxes and inverse S-boxes for block cipher systems. The quality of this algorithm was tested by using NIST tests, and changing only one bit of the secret key to generate new key-dependent S-boxes. The fact that the S-boxes are key-dependent and unknown is the main strength of the algorithm, since the linear and differential cryptanalysis require known S-boxes. In the second section of the paper, we analyze S-boxes. In the third section we describe the key-dependent S-boxes and inverse S-boxes generation algorithm. Afterwards, we experimentally investigate the quality of the generated key-dependent S-boxes. Comparison results suggest that the key-dependent S-boxes have good performance and can be applied to AES.
45 citations
TL;DR: GOST 28147-89 is a well-known block cipher and it was submitted to ISO 18033 to become a worldwide industrial encryption standard in 2010 as discussed by the authors, but it was not broken until 2010.
Abstract: GOST 28147-89 is a well-known block cipher. Its large key size of 256 bits and incredibly low implementation cost make it a plausible alternative for AES-256 and triple DES. Until 2010 "despite considerable cryptanalytic efforts spent in the past 20 years", GOST was not broken see [30]. Accordingly, in 2010 GOST was submitted to ISO 18033 to become a worldwide industrial encryption standard.
In paper we focus on the question of how far one can go in a dedicated Depth-First-Search approach with several stages of progressive guessing and filtering with successive distinguishers. We want to design and optimized guess-then-truncated differential attack on full 32-bit GOST and make as efficient as we can.The main result of this paper is a single-key attack against full 32-round 256-bit GOST with time complexity of $$2^{179}$$ which is substantially faster than any other known single key attack on GOST.
41 citations
10 Sep 2015
TL;DR: This work compares unrolled combinational hardware implementations of six lightweight block ciphers, along with an AES implementation as a baseline, to show that some designers are already on this track, but a lot of work still remains to be done.
Abstract: Security mechanisms to protect our systems and data from malicious adversaries have become essential. Strong encryption algorithms are an important building block of these solutions. However, each application has its own requirements and it is not always possible to find a cipher that meets them all. This work compares unrolled combinational hardware implementations of six lightweight block ciphers, along with an AES implementation as a baseline. Up until now, the majority of such ciphers were designed for area-constrained environments where speed is often not crucial, but recently the need for single-cycle, low-latency block ciphers with limited area requirements has arisen to build security architectures for embedded systems. Our comparison shows that some designers are already on this track, but a lot of work still remains to be done.
TL;DR: In this paper, a quantum version of differential cryptanalysis is proposed, which offers a quadratic speedup over the existing classical one and shows the quantum circuit implementing it, where the values to be compared and filtered are obtained by calling the quantum counting algorithm.
Abstract: In this paper, we propose a quantum version of the differential cryptanalysis which offers a quadratic speedup over the existing classical one and show the quantum circuit implementing it. The quantum differential cryptanalysis is based on the quantum minimum/maximum-finding algorithm, where the values to be compared and filtered are obtained by calling the quantum counting algorithm. Any cipher which is vulnerable to the classical differential cryptanalysis based on counting procedures can be cracked more quickly under this quantum differential attack.
TL;DR: It is demonstrated that the claim that this cipher has high security and can resist different well-known attacks is not reasonable, since the cipher can be broken by chosen plaintext attack with the complexity O(αβ), where α and β represent the number of the image rows and columns, respectively.
Abstract: In recent years, it is popular that the combination of chaos and DNA is employed for image ciphers. There have been a great number of image ciphers which are designed based on chaos and DNA, but the corresponding cryptanalytic works are insufficient and in-depth study should be made. In this paper, we decipher an image cipher combining a 3-cell chaotic map with DNA. It was claimed that this cipher has high security and can resist different well-known attacks. However, we demonstrate that the claim is not reasonable, since the cipher can be broken by chosen plaintext attack with the complexity $$O({\alpha \beta })$$
, where $$\alpha $$
and $$\beta $$
represent the number of the image rows and columns, respectively.
16 Aug 2015
TL;DR: This article proposes a known-key distinguisher on the full PRESENT, both 80- and 128-bit key versions, and stresses that this is the very first attack that can reach the full number of rounds of the PRESENT block cipher.
Abstract: In this article, we analyse the known-key security of the standardized PRESENT lightweight block cipher. Namely, we propose a known-key distinguisher on the full PRESENT, both 80- and 128-bit key versions. We first leverage the very latest advances in differential cryptanalysis on PRESENT, which are as strong as the best linear cryptanalysis in terms of number of attacked rounds. Differential properties are much easier to handle for a known-key distinguisher than linear properties, and we use a bias on the number of collisions on some predetermined input/output bits as distinguishing property. In order to reach the full PRESENT, we eventually introduce a new meet-in-the-middle layer to propagate the differential properties as far as possible. Our techniques have been implemented and verified on the small scale variant of PRESENT. While the known-key security model is very generous with the attacker, it makes sense in practice since PRESENT has been proposed as basic building block to design lightweight hash functions, where no secret is manipulated. Our distinguisher can for example apply to the compression function obtained by placing PRESENT in a Davies-Meyer mode. We emphasize that this is the very first attack that can reach the full number of rounds of the PRESENT block cipher.
TL;DR: A 3D object encryption scheme, based on a series of random permutations and rotations, which deform the geometry of the point cloud, which demonstrates the security, effectiveness, and robustness of the proposed cipher against surface reconstruction attacks.
Abstract: Due to widespread applications of 3D vision technology, the research into 3D object protection is primarily important. To maintain confidentiality, encryption of 3D objects is essential. However, the requirements and limitations imposed by 3D objects indicate the impropriety of conventional cryptosystems for 3D object encryption. This suggests the necessity of designing new ciphers. In addition, the study of prior works indicates that the majority of problems encountered with encrypting 3D objects are about point cloud protection, dimensional and spatial stability, and robustness against surface reconstruction attacks. To address these problems, this paper proposes a 3D object encryption scheme, based on a series of random permutations and rotations, which deform the geometry of the point cloud. Since the inverse of a permutation and a rotation matrix is its transpose, the decryption implementation is very efficient. Our statistical analyses show that within the cipher point cloud, points are randomly distributed. Furthermore, the proposed cipher leaks no information regarding the geometric structure of the plain point cloud, and is also highly sensitive to the changes of the plaintext and secret key. The theoretical and experimental analyses demonstrate the security, effectiveness, and robustness of the proposed cipher against surface reconstruction attacks.
TL;DR: This paper proposes a very efficient new class of diffusion layers constructed from several rounds of Feistel-like structures whose round functions are linear, and investigates the requirements of the underlying linear functions to achieve the maximal branch number for the proposed 4×4 words diffusion layer.
Abstract: Many modern block ciphers use maximum distance separable (MDS) matrices as the main part of their diffusion layers. In this paper, we propose a very efficient new class of diffusion layers constructed from several rounds of Feistel-like structures whose round functions are linear. We investigate the requirements of the underlying linear functions to achieve the maximal branch number for the proposed 4×4 words diffusion layer, which is an indication of the highest level of security with respect to linear and differential attacks. We try to extend our results for up to 8×8 words diffusion layers. The proposed diffusion layers only require simple operations such as word-level XORs, rotations, and they have simple inverses. They can replace the diffusion layer of several block ciphers and hash functions in the literature to increase their security, and performance. Furthermore, it can be deployed in the design of new efficient lightweight block ciphers and hash functions in future.
8 Mar 2015
TL;DR: A new method to construct truncated differential characteristics of block ciphers using the meet-in-the-middle like technique is introduced and 10-round and 8-round truncation differential characteristics are proposed for CLEFIA and Camellia, respectively, which are ISO standard block cIPhers.
Abstract: As one of the generalizations of differential cryptanalysis, the truncated differential cryptanalysis has become a powerful toolkit to evaluate the security of block ciphers. In this article, taking advantage of the meet-in-the-middle like technique, we introduce a new method to construct truncated differential characteristics of block ciphers. Based on the method, we propose 10-round and 8-round truncated differential characteristics for CLEFIA and Camellia, respectively, which are ISO standard block ciphers. Applying the 10-round truncated differential characteristic for CLEFIA, we launch attacks on 14/14/15-round CLEFIA-128/192/256 with \(2^{108}\), \(2^{135}\) and \(2^{203}\) encryptions, respectively. For Camellia, we utilize the 8-round truncated differential to attack 11/12-round Camellia-128/192 including the \(FL/FL^{-1}\) and whiten layers with \(2^{121.3}\) and \(2^{185.3}\) encryptions. As far as we know, most of the cases are the best results of these attacks on both ciphers.
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TL;DR: The leaked-state-forgery attack LSFA is proposed, which shows that the authentication security of ALE is only 97-bit, and the results may be further improved to around 93-bit if the whitening key layer is removed.
Abstract: ALE is a new authenticated encryption algorithm published at FSE 2013. The authentication component of ALE is based on the strong Pelican MAC, and the authentication security of ALE is claimed to be 128-bit. In this paper, we propose the leaked-state-forgery attack (LSFA) against ALE by exploiting the state information leaked from the encryption of ALE. The LSFA is a new type of differential cryptanalysis in which part of the state information is known and exploited to improve the differential probability. Our attack shows that the authentication security of ALE is only 97-bit. And the results may be further improved to around 93-bit if the whitening key layer is removed. We implemented our attacks against a small version of ALE (using 64-bit block size instead of 128-bit block size). The experimental results match well with the theoretical results.
1 Nov 2015
TL;DR: This paper is the first one to give zero-correlation linear approximations of SIMON64, SIMON96 and SIMON128, which are also utilized to attack the corresponding ciphers.
Abstract: SIMON is a family of lightweight block ciphers publicly released by the NSA. Up to now, there have been many cryptanalytic results on it by means of differential, linear, impossible differential, integral, zero-correlation linear cryptanalysis and so forth. At INDOCRYPT 2014, Wang et al. gave zero-correlation attacks for 20-round SIMON32, 20-round SIMON48/72 and 21-round SIMON48/96. We investigate the security of whole family of SIMON by using zero-correlation linear cryptanalysis in this paper. For SIMON32 and SIMON48, we can attack one more round than the previous zero-correlation attacks given by Wang et al. We are the first one to give zero-correlation linear approximations of SIMON64, SIMON96 and SIMON128. These approximations are also utilized to attack the corresponding ciphers.
TL;DR: In this article, the authors evaluate the security of the lightweight block cipher KLEIN-64 using biclique cryptanalysis and present a modified version of this cryptanalysis which is slightly faster at the expense of the data required.
Abstract: In this study, the authors evaluate the security of the lightweight block cipher KLEIN-64 using biclique cryptanalysis. They first point out some new weaknesses of the diffusion layer and key schedule of this algorithm. Then they exploit them to cryptanalyst the full round version of KLEIN-64 using an asymmetric biclique. The (worst case) computations and data complexity of this cryptanalysis are 262.84 and 239, respectively. A modified version of this cryptanalysis is also presented which is slightly faster at the expense of the data required.
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TL;DR: In this article, the authors improved previously published linear trail bias estimations by presenting a novel method to calculate the bias of short linear hulls in Simon and use them to construct longer linear approximations.
Abstract: Simon is a family of block ciphers designed by the NSA and published in 2013. Due to their simple structure and the fact that the specification lacked security design rationale, the ciphers have been the subject of much cryptanalytic work, especially using differential and linear cryptanalysis. We improve previously published linear trail bias estimations by presenting a novel method to calculate the bias of short linear hulls in Simon and use them to construct longer linear approximations. By using these linear approximations we present key recovery attacks of up to 25 rounds for Simon64/128, 24 rounds for Simon32/64, Simon48/96, and Simon64/96, and 23 rounds for Simon48/72. The attacks on Simon32 and Simon48 are currently the best attacks on these versions. The attacks on Simon64 do not cover as many rounds as attacks using differential cryptanalysis but they work in the more natural setting of known plaintexts rather than chosen plaintexts.
TL;DR: The objective of the proposed work is to make the existing cipher techniques more prone to cryptanalysis by incorporating the proposed S-box in the design which employs a set of differential equations called Lorenz equations with given initial parameters.
Abstract: In cryptography, the security of any algorithm relies on the strength of the key used and nonlinear mapping of the original information or data. It is desirable to have resistance against differential cryptanalysis, which assists in providing clues about the composition of keys, and linear secret system, where a simple approximation is created to copy the original cipher characteristics. The objective of the proposed work is to make the existing cipher techniques more prone to cryptanalysis by incorporating the proposed S-box in the design. In this paper, the use of nonlinear functional chaos-based substitution process is proposed which employs a set of differential equations called Lorenz equations with given initial parameters. The performance of the new substitution box is evaluated through simulation and data analytics tool. During testing, it has been found that the proposed technique produces high Standard Deviation (112.84) and negative correlation factor (-0.161) which makes it applicable where security against cryptanalysis is a major concern.
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TL;DR: In this paper, the security of the 64-bit SIMON with 128-bit key against advanced forms of differential cryptanalysis using truncated differentials has been studied and a 22-round distinguisher has been proposed.
Abstract: Lightweight cryptography is a rapidly evolving area of research and it has great impact especially on the new computing environment called the Internet of Things (IoT) or the Smart Object networks (Holler et al., 2014), where lots of constrained devices are connected on the Internet and exchange information on a daily basis. Every year there are many new submissions of cryptographic primitives which are optimized towards both software and hardware implementation so that they can operate in devices which have limited resources of hardware and are subject to both power and energy consumption constraints. In 2013, two families of ultra-lightweight block ciphers were proposed, SIMON and SPECK, which come in a variety of block and key sizes and were designed to be optimized in hardware and software implementation respectively (Beaulieu et al., 2013). In this paper, we study the security of the 64-bit SIMON with 128-bit key against advanced forms of differential cryptanalysis using truncated differentials (Knudsen, 1995; Courtois et al., 2014a). We follow similar method as the one proposed in SECRYPT 2013 (Courtois and Mourouzis, 2013) in order to heuristically discover sets of differences that propagate with sufficiently good probability and allow us to combine them efficiently in order to construct large-round statistical distinguishers. We present a 22-round distinguisher which we use it in a depth-first key search approach to develop an attack against 24 and 26 rounds with complexity 2^{124.5} and 2^{126} SIMON encryptions respectively. Our methodology provides a framework for extending distinguishers to attacks to a larger number of rounds assuming truncated differential properties of relatively high probability were discovered.
23 Aug 2015
TL;DR: A simple solving algorithm exploiting many variables in the cipher states coming from different plaintexts are linearly related, giving efficient algebraic attacks on up to 16 rounds of the largest Simon variants.
Abstract: This paper focuses on algebraic attacks on the Simon family of block ciphers. We construct equation systems using multiple plaintext/ciphertext pairs, and show that many variables in the cipher states coming from different plaintexts are linearly related. A simple solving algorithm exploiting these relations is developed and extensively tested on the different Simon variants, giving efficient algebraic attacks on upi?źto 16 rounds of the largest Simon variants.
TL;DR: This work uses new techniques for the cryptanalysis of hash functions to find a collision of the full SHA-0 which is the first published collision of this function, and very efficient collision attacks on reduced versions of SHA-1.
Abstract: We present new techniques for the cryptanalysis of hash functions. Our contributions are two-fold: both on the search level of the compression function and on the meta-structure. The former led to the neutral bits technique, while the latter led to the multi-block technique. The usefulness of these techniques is demonstrated on SHA-0 and SHA-1, but they are applicable to other hash functions as well. We use these techniques to find a collision of the full SHA-0 which is the first published collision of this function, and very efficient collision attacks on reduced versions of SHA-1.
15 May 2015
TL;DR: A new modified version of RC6 referred to as MC-RC6 with enhanced security and performance better than AES is introduced with obtained numerical values show that there is always a tradeoff between security and the network performance.
Abstract: In this paper, we have presented comparative performance analysis of symmetric key algorithms particularly of block ciphers. Performance evaluation of various block ciphers has been carried out in terms of encryption time, avalanche effect, throughput, CPU time, and power consumption. The obtained numerical values show that there is always a tradeoff between security and the network performance. RC6 outperforms the AES for all the parameters except security. We have introduced a new modified version of RC6 referred to as MC-RC6 with enhanced security and performance better than AES.
TL;DR: It appears that the choice of S-boxes has a limited effect on the actual security of GOST against advanced differential attacks, and there is no evidence that the version of GoST submitted to ISO in 2011 is stronger than any previous version ofGOST.
Abstract: Nothing can be more mistaken. In this article, the authors review 40 years of development of block ciphers in order to resist differential attacks. They study all ten known sets of GOST S-boxes. It appears that the choice of S-boxes has a limited effect on the actual security of GOST against advanced differential attacks. There is no evidence that the version of GOST submitted to ISO in 2011 is stronger than any previous version of GOST.
TL;DR: The first white‐box AES (WB‐AES) implementation is revisited and a conditional re‐encoding method for cryptanalysis protection is presented and the experimental results show that there is approximately a 57% increase in the memory requirement and a 20% increased in execution speed.
Abstract: Conventional cryptographic algorithms are not sufficient to protect secret keys and data in white-box environments, where an attacker has full visibility and control over an executing software code. For this reason, cryptographic algorithms have been redesigned to be resistant to white-box attacks. The first white-box AES (WB-AES) implementation was thought to provide reliable security in that all brute force attacks are infeasible even in white-box environments; however, this proved not to be the case. In particular, Billet and others presented a cryptanalysis of WB-AES with 230 time complexity, and Michiels and others generalized it for all substitution-linear transformation ciphers. Recently, a collision-based cryptanalysis was also reported. In this paper, we revisit Chow and others's first WB-AES implementation and present a conditional re-encoding method for cryptanalysis protection. The experimental results show that there is approximately a 57% increase in the memory requirement and a 20% increase in execution speed.
28 Apr 2015
TL;DR: It is concluded that Genetic Algorithm is a better approach than the Brute Force for analyzing SDES.
Abstract: Cryptanalysis of cipher text using evolutionary algorithm has gained much interest in the last decade. In this paper, cryptanalysis of SDES has been performed using Genetic Algorithm with Ring Crossover operator. Cryptography has been prone to many attacks but the scope of this paper is limited only to the cipher text attack. Different combinations of keys are generated using the Genetic Algorithm and hence it is concluded that Genetic Algorithm is a better approach than the Brute Force for analyzing SDES.
1 Sep 2015
TL;DR: This paper will study the algorithm factors that affect finding solution taking in consideration the time and efficiency of the cryptanalysis process, the Different type of crossover, population size and mutation rate that used to find the optimal solution.
Abstract: A Genetic algorithm is a search tool that's used to insure high probability of finding a solution by decreasing the amount of time in key space searching. In this paper the focus will be on the cryptanalysis of a Hill cipher by using genetic algorithm and study the algorithm factors that affect finding solution taking in consideration the time and efficiency of the cryptanalysis process, the Different type of crossover, population size and mutation rate that used to find the optimal solution.