Deliberate injection of faults into cryptographic devices is an effective cryptanalysis technique against symmetric and asymmetric encryption algorithms. In this paper we will describe parity code based concurrent error detection (CED) approach against such attacks in substitution-permutation network (SPN) symmetric block ciphers [22]. The basic idea compares a carefully modified parity of the input plain text with that of the output cipher text resulting in a simple CED circuitry. An analysis of the SPN symmetric block ciphers reveals that on one hand, permutation of the round outputs does not alter the parity from its input to its output. On the other hand, exclusive-or with the round key and the non-linear substitution function (s-box) modify the parity from their inputs to their outputs. In order to change the parity of the inputs into the parity of outputs of an SPN encryption, we exclusive-or the parity of the SPN round function output with the parity of the round key. We also add to all s-boxes an additional 1-bit binary function that implements the combined parity of the inputs and outputs to the s-box for all its (input, output) pairs. These two modifications are used only by the CED circuitry and do not impact the SPN encryption or decryption. The proposed CED approach is demonstrated on a 16-input, 16-output SPN symmetric block cipher from [1].

Parity-based concurrent error detection of substitution-permutation network block ciphers

This paper proposes preimage attacks on hash function HAVAL whose output length is 256 bits. This paper has three main contributions; a preimage attack on 3-pass HAVAL at the complexity of 2225, a preimage attack on 4-pass HAVAL at the complexity of 2241, and a preimage attack on 5-pass HAVAL reduced to 151 steps at the complexity of 2241. Moreover, we optimize the computational order for brute-force attack on full 5-pass HAVAL and its complexity is 2254.89. As far as we know, the proposed attack on 3-pass HAVAL is the best attack and there is no preimage attack so far on 4-pass and 5-pass HAVAL. Note that the complexity of the previous best attack on 3-pass HAVAL is 2230. Technically, our attacks find pseudo-preimages of HAVAL by combining the meet-in-the-middle and local-collision approaches, then convert pseudo-preimages to a preimage by using a generic algorithm.

/pdf/preimage-attacks-on-3-4-and-5-pass-haval-tl93u4gitr.pdf

Preimage Attacks on 3, 4, and 5-Pass HAVAL

In the modern era of secure communication, it is important to create uncertainty in the original data in order to avoid unauthorized entities to extract or manipulate information. From simple methods such as permutations of original data to different mapping algorithms, the security of the ciphers rely on the substitution process. There are many types of components proposed in literature that are evolved by different methodologies and ideas. The prevailing ciphers use substitution boxes (S-boxes) to do this transformation process. In this work, we present a literature review of the design, construction, and analysis of the S-boxes used in block ciphers. The performance of S-boxes depends on the design and algebraic structure used for the construction and is contingent upon its ability to resist against cryptanalysis. We present the details of the S-box synthesis process and issues pertaining to creating resistance against various types of attacks, and highlight the consequences of a particular design methodology. In the infancy of the development of modern block ciphers, Shannon (Bell Syst. Tech. J. 28(4):656–715, 1949) presented the idea of encryption with the implementation of substitution-permutation network (SPN). In this process, the data is initially transformed by the substation process and then permuted that ends the first round supported by the secret key for this step. This substitution-permutation process is repeated several times to ensure reliability of encrypted data. The objective of using the substitution-permutation network is to create confusion between cipher text and secret key, and add diffusion in the plaintext.

Literature survey on nonlinear components and chaotic nonlinear components of block ciphers

In this paper, we present a fast attack algorithm to find two-block collision of hash function MD5. The algorithm is based on the two-block collision differential path of MD5 that was presented by Wang et al. in the Conference EUROCRYPT 2005. We found that the derived conditions for the desired collision differential path were not sufficient to guarantee the path to hold and that some conditions could be modified to enlarge the collision set. By using technique of small range searching and omitting the computing steps to check the characteristics in the attack algorithm, we can speed up the attack of MD5 efficiently. Compared with the Advanced Message Modification technique presented by Wang et al., the small range searching technique can correct 4 more conditions for the first iteration differential and 3 more conditions for the second iteration differential, thus improving the probability and the complexity to find collisions. The whole attack on the MD5 can be accomplished within 5 hours using a PC with Pentium4 1.70GHz CPU.

/pdf/improved-collision-attack-on-hash-function-md5-24v71jsx9j.pdf

Improved collision attack on hash function MD5

Cryptanalysis of an EPC Class-1 Generation-2 Standard Compliant Authentication Protocol

In this paper, we present a new approach for cryptanalysis of four-round DES based on genetic algorithm. An efficient fitness measure is used to find some optimum keys with higher fitness values. Some valuable bits in these optimum keys which generate apparent deviation from the other observed bits will turn up. Then, these valuable bits can be applied to find other bits. The results indicate that genetic algorithm is successful at breaking the four-round DES cipher, but perhaps more significantly, this is a promising method applied to break other Feistel block cipher.

Cryptanalysis of Four-Round DES Based on Genetic Algorithm

A novel algorithm enumerating bent functions

By some basic transforms and invariant theory, we give two results: 1) an algorithm, which can be used to judge if two Boolean functions are affinely equivalent and to obtain the equivalence relationship if they are equivalent. This is useful in studying Boolean functions and in engineering. For example, we classify all 8-variable homogeneous bent functions of degree 3 into two classes; 2) Reed-Muller codes R(4,6)/R(1,6), R(3,7)/R(1,7) are classified efficiently.

Analysis of affinely equivalent Boolean functions

Based on a theorem on the construction of a permutation, we propose an evolutionary algorithm that can efficiently design S-boxes with good cryptographic properties like high nonlinearity, low autocorrelation, low difference and high algebraic immunity. Furthermore, we observe that the polynomial representing a concrete designed S-box over a small field can be generalized to that over a large field. That is, we not only can design many concrete S-boxes, but also may find many types of affinely in equivalent S-boxes.

Evolutionary Design of S-Box with Cryptographic Properties

Cryptanalysis with genetic algorithm has attracted much interest in recent years. This paper presents an approach for the cryptanalysis of two-round DES based on genetic algorithm. However, cryptanalysis of two-round DES using genetic algorithm is usually a difficult task. In this paper, we adopt known plaintext attack and produce a variety of optimum keys based on fitness function. Furthermore, we count every bit of optimal keys one by one, and find some valuable bits, which generate a significant deviation from the other observed bits. Finally, the 56-bit key is successfully gained without searching the whole search space. The experimental result indicates that this is a promising method and can be adopted to handle other complex block ciphers.

Qingshu Meng

Papers

Cryptanalysis of Four-Round DES Based on Genetic Algorithm

A novel algorithm enumerating bent functions

Analysis of affinely equivalent Boolean functions

Evolutionary Design of S-Box with Cryptographic Properties

Cryptanalysis of two-round DES using genetic algorithms