A New MAC Construction ALRED and a Specific Instance ALPHA-MAC

This paper reviews constructions of hash functions and MAC algorithms based on block ciphers. It discusses the main requirements for these cryptographic primitives, motivates these constructions, and presents the state of the art of both attacks and security proofs.KeywordsHash FunctionSecurity LevelBlock CipherCompression FunctionSecurity ProofThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

IDEA is an iterated block cipher proposed by Lai and Massey and is based on the design concept of “mixing operations from different algebraic groups”. New arithmetic properties of the basic operations used in the round function are found and investigated with respect to the security of this block cipher. Evidence is given that these properties can be exploited in the cryptanalysis of the first 2 rounds of IDEA but that they are of no assistance in the cryptanalysis of the full IDEA block cipher containing 8 rounds.KeywordsBlock CipherOutput DifferenceArithmetic PropertyRound FunctionOutput TransformationThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

This paper proposes a nested (hierarchical) SPN structure and the symmetric block cipher “Hierocrypt”. In the nested SPN structure, lower-level SPN structures are recursively embedded into S-box positions in SPN of the higher level. This structure recursively assures the lower bound of active S-box number, and high security level is efficiently realized. The 8-round Hierocrypt is implemented in C language on Pentium III, and shows the middle-class performance of final AES candidates.KeywordsBlock CipherLinear Feedback Shift RegisterRound FunctionMaximum Distance SeparableHigh Security LevelThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Westfeld[1] detected the stegoed–image by measuring the frequencies of PoVs(pairs of values) in the suspicious images. Fridrich[4] proposed another detection method, so-called RS steganalysis. In this paper we propose a steganographic scheme using a block cipher, which minimizes the embedding changes of a cover object utilizing not only the LSBs of the cover object’s strings but also the whole bits of the cover object. The proposed scheme is a kind of the coding scheme which minimizes changed bits for message embedding without sharing the secret code–book. The experimental result shows that the proposed scheme efficiently evades the χ 2–statistical test and RS steganalysis.KeywordsSecret MessageBlock CipherCipher TextCover ObjectMessage BlockThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Most last-round attacks on iterated block ciphers provide some design criteria for the round function. Here, we focus on the links between the underlying properties. Most notably, we investigate the relations between the functions which oppose a high resistance to linear cryptanalysis and to differential cryptanalysis.KeywordsBlock CipherCyclic CodeBend FunctionLinear Feedback Shift RegisterRound FunctionThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Controlled two-place operations (CTPO) are introduced as a new cryptographic primitive for the block ciphers. Design criteria, structure, some good cryptographic properties of the CTPO are considered. There are proposed CTPO representing single nonlinear operations on the operands of relatively large length. It is shown that CTPO in combination with the controlled permutations (CP) can be efficiently used to construct fast block ciphers. Three different cryptoschemes based on data-dependent two-place operations and data-dependent permutations are presented. A feature of the cryptoschemes is the use of the CTPO and CP for construction of some mechanisms of the internal key scheduling which consists in data-dependent transformation of the round keys.KeywordsBlock CipherEncryption FunctionRound FunctionBent FunctionCryptographic PrimitiveThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

This paper provides an overview of the state of the art in the design of cryptographic algorithms. It reviews the different type of algorithms for encryption and authentication and explains the principles of stream ciphers, block ciphers, hash functions, public-key encryption algorithms, and digital signature schemes. Subsequently the design and evaluation procedures for cryptographic algorithms are discussed.KeywordsHash FunctionEncryption AlgorithmBlock CipherStream CipherCryptographic AlgorithmThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

In this paper, we improve on a previous result by Gagné et al. [9] for automatically proving the semantic security of symmetric modes of operation for block ciphers. We present a richer assertion language that uses more flexible invariants, and a more complete set of rules for establishing the invariants. In addition, all our invariants are given a meaningful semantic definition, whereas some invariants of the previous result relied on more ad hoc definitions. Our method can be used to verify the semantic security of all the encryption modes that could be proven secure in [9], in addition to other modes, such as Propagating Cipher-Block Chaining (PCBC).KeywordsBlock CipherMessage Authentication CodeRandom Oracle ModelSymmetric EncryptionEncryption ModeThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Dedicated hash functions are cryptographically secure compression functions which are designed specifically for hashing. They intend to form a practical alternative for hash functions based on another cryptographic primitive like a block cipher or modular squaring. About a dozen of dedicated hash functions have been proposed in the literature. This paper discusses the design principles on which these hash functions are based.KeywordsHash FunctionBlock CipherStream CipherRound FunctionLinear CryptanalysisThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

In this paper, we present an algebraic attack against the Flurry and Curry block ciphers [12,13]. Usually, algebraic attacks against block ciphers only require one message/ciphertext pair to be mounted. In this paper, we investigate a different approach. Roughly, the idea is to generate an algebraic system from the knowledge of several well chosen correlated message/ciphertext pairs. Flurry and Curry are two families of ciphers which fully parametrizable and having a sound design strategy against the most common statistical attacks; i.e. linear and differential attacks. These ciphers are then targets of choices for algebraic attacks. It turns out that our new approach permits to go one step further in the (algebraic) cryptanalysis of difficult instances of Flurry and Curry. To explain the behavior of our attack, we have established an interesting connection between algebraic attacks and high order differential cryptanalysis [32]. From extensive experiments, we estimate that our approach – that we will call ”algebraic-high order differential” cryptanalysis – is polynomial when the Sbox is a power function. As a proof of concept, we have been able to break Flurry/Curry – up to 8 rounds – in few hours. We have also investigated the more difficult (and interesting case) of the inverse function. For such function, we have not been able to bound precisely the theoretical complexity, but our experiments indicate that our approach permits to obtain a significant practical gain. We have attacked Flurry/Curry using the inverse Sbox up to 8 rounds.KeywordsBlock CipherBasis ComputationPolynomial SystemStream CipherAlgebraic DegreeThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

S-boxes constitute a cornerstone component in symmetric-key cryptographic algorithms, such as DES and AES encryption systems. In block ciphers, they are typically used to obscure the relationship between the plaintext and the ciphertext. Non-linear and non-correlated S-boxes are the most secure against linear and differential cryptanalysis. In this paper, we focus on a two-fold objective: first, we evolve regular an S-box with high non-linearity and low auto-correlation properties using evolutionary computation; then automatically generate evolvable hardware for the obtained S-box. Targeting the former, we use the Nash equilibrium-based multi-objective evolutionary algorithm to optimise regularity, non-linearity and auto- correlation, which constitute the three main desired properties in resilient S-boxes. Pursuing the latter, we exploit genetic programming to automatically generate the evolvable hardware designs of substitution boxes that minimise hardware space, encryption/decryption time and dissipated power, which form the three main hardware characteristics. We compare our results against existing and well-known designs, which were produced by using conventional methods as well as through evolution.KeywordsNash EquilibriumCrossover OperatorHardware ImplementationBlock CipherEvolutionary DesignThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Type-I generalized Feistel networks (GFN) are widely used frameworks in symmetric-key primitive designs such as CAST-256 and Lesamnta. Different from the extensive studies focusing on specific block cipher instances, the analysis against Type-I GFN structures gives generic security evaluation of the basic frameworks and concentrates more on the effect of linear transformation. Currently, works in this field mainly evaluate the security against impossible differential attack, zero-correlation linear attack, meet-in-the-middle attack and yoyo game attack, while its security evaluation against rectangle attack is still missing. In this paper, we filled this gap and gave the first structural analytical results of Type-I GFN against rectangle attack. By exploiting its structural properties, we proved there exists a boomerang switch for Type-I GFN for the first time, which is independent of the round functions. Then we turned the boomerang switch into chosen plaintext setting and proposed a new rectangle attack model. By appending 1 more round in the beginning of the boomerang switch, we constructed a rectangle distinguisher and a key recovery attack could be performed.

While traditional approaches in object recognition require the specification of training examples from each class and the application of class specific classifiers, in real world situations, the immensity of the number of image classes makes this task daunting. A novel approach in object recognition is attribute based classification, where instead of training classifiers for the recognition of specific object class instances, classifiers are trained on attributes of the object images and these attributes are subsequently used for the object recognition. The attributes based paradigm offers significant advantages including the ability to train classifiers without any visual examples. We begin by discussing a scenario for object recognition on mobile devices where the attribute prediction and the attribute-to-class mapping are decoupled in order to meet the specific resource constraints of mobile systems. We next present two extensions on the attribute based classification paradigm by introducing alternative approaches in attribute prediction and attribute-to-class mapping. For the attribute prediction, we employ the recently proposed Sparse Representations Classification scheme that offers significant benefits compared to the previous SVM based approaches, such as increased accuracy and elimination of the training stage. For the attribute-to-class mapping, we employ a Distance Metric Learning algorithm that automatically infers the significance of each attribute instead of assuming uniform attribute importance. The benefits of the proposed extensions are validated through experimental results.

In this paper, we apply multiple linear cryptanalysis to a reduced round RC6 block cipher. We show that 18-round RC6 with weak key is breakable by using the multiple linear attack.KeywordsLinear ApproximationBlock CipherLinear CharacteristicAdvance Encryption StandardLinear ProbabilityThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Supervisory Control And Data Acquisition (SCADA) systems are real-time process control systems that are widely deployed throughout critical infrastructure sectors including power, gas, oil, and water. However, SCADA networks generally have little protection from the rising danger of cyber attack. A retrofit solution to protect existing SCADA communications links must assure the integrity of commands and responses that are typically transmitted over serial lines at speeds from 300 to 19200 bits per second, while introducing minimal additional latency into the real-time SCADA traffic.This paper describes the key aspects of a cryptographic protocol for retrofit SCADA link protection that leverages the Cyclic Redundancy Checks (CRC) transmitted by existing SCADA equipment to achieve strong integrity while introducing minimal latency. The protocol is based on a new position embedding encryption mode which, for a b-bit block cipher, ensures that any unauthentic message an adversary can construct (i) includes at least b randomly chosen bits, and therefore, by a new result proved for error detection by systematic shortened cyclic codes, (ii) contains a correct h-bit CRC with probability 2 − h. The low speed of the communications channel limits the rate at which an adversary can make trials, enabling detection of potential attacks before enough trials can be made to achieve any significant likelihood of success. The protocol avoids the need for a decrypting link protection module to buffer decrypted data until an end-of-message integrity check is verified, which would otherwise add significant latency.KeywordsBlock CipherAdvance Encryption StandardCyclic CodeMessage Authentication CodeCyclic Redundancy CodeThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.