Fast Correlation Attacks Based on Turbo Code Techniques

Johansson, Thomas; Jönsson, Fredrik

doi:10.1007/3-540-48405-1_12

Cited by 62 publications

(67 citation statements)

References 15 publications

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“…Several minor improvements of this original attack were proposed in [21,12,1,13,15] but these papers did not introduce any important modification of the basic underlying concepts. Johansson and Jönsson recently proposed two new techniques for fast correlation attacks: the main idea is to derive from (s n ) n<N a sequence which can be seen as a corrupted version of a word of a convolutional code [6] or of a turbo code [7]. These new attacks increase the highest achievable error probability p for given values of L and N (L is the length of the LFSR generating σ and N is the number of known bits of the running-key).…”

Section: Fig 2 Correlation Attack Involving K Constituent Lfsrsmentioning

confidence: 99%

Improved Fast Correlation Attacks Using Parity-Check Equations of Weight 4 and 5

Canteaut

Trabbia

2000

Advances in Cryptology — EUROCRYPT 2000

167

159

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Abstract. This paper describes new techniques for fast correlation attacks, based on Gallager iterative decoding algorithm using parity-check equations of weight greater than 3. These attacks can be applied to any key-stream generator based on LFSRs and it does not require that the involved feedback polynomial have a low weight. We give a theoretical analysis of all fast correlation attacks, which shows that our algorithm with parity-check equations of weight 4 or 5 is usually much more efficient than correlation attacks based on convolutional codes or on turbo codes. Simulation results confirm the validity of this comparison. In this context, we also point out the major role played by the nonlinearity of the Boolean function used in a combination generator.

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Section: Fig 2 Correlation Attack Involving K Constituent Lfsrsmentioning

confidence: 99%

Improved Fast Correlation Attacks Using Parity-Check Equations of Weight 4 and 5

Canteaut

Trabbia

2000

Advances in Cryptology — EUROCRYPT 2000

167

159

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“…In stream ciphers applications, when f is used in a pseudo-random generator as a combining function or as a filtering function, the existence of a "good" approximation of f by an affine function makes fast correlation attacks feasible [17,13,12]. Similarly, if f is used in a block cipher as an S-box component, this would lead to successful linear attacks [15].…”

Section: Cryptographic Criteria For Boolean Functionsmentioning

confidence: 99%

Propagation Characteristics and Correlation-Immunity of Highly Nonlinear Boolean Functions

Canteaut

Carlet

Charpin

et al. 2000

Advances in Cryptology — EUROCRYPT 2000

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Abstract. We investigate the link between the nonlinearity of a Boolean function and its propagation characteristics. We prove that highly nonlinear functions usually have good propagation properties regarding different criteria. Conversely, any Boolean function satisfying the propagation criterion with respect to a linear subspace of codimension 1 or 2 has a high nonlinearity. We also point out that most highly nonlinear functions with a three-valued Walsh spectrum can be transformed into 1-resilient functions.

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“…fast correlation attacks (Meier,Staffelbach [18], Chepyzhov, Smeets [5], Johansson, Joensson [12,13]), backtracking attacks (Golic [10], Zenner, Krause, Lucks [24], Fluhrer, Lucks [9], Zenner [23]), time-space tradeoffs (Biryukov, Shamir [4]), BDD-based attacks (Krause [15]) etc. For such stream ciphers many corresponding design criteria (correlation immunity, large period and linear complexity, good local statistics etc.)…”

Section: Introductionmentioning

confidence: 99%

Improving Fast Algebraic Attacks

Armknecht

2004

Fast Software Encryption

127

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Abstract. An algebraic attack is a method for cryptanalysis which is based on finding and solving a system of nonlinear equations. Recently, algebraic attacks where found helpful in cryptanalysing LFSR-based stream ciphers. The efficiency of these attacks greatly depends on the degree of the nonlinear equations. At Crypto 2003, Courtois [8] proposed Fast Algebraic Attacks. His main idea is to decrease the degree of the equations using a precomputation algorithm. Unfortunately, the correctness of the precomputation step was neither proven, nor was it obvious. The three main results of this paper are the following: First, we prove that Courtois' precomputation step is applicable for cryptographically reasonable LFSR-based stream ciphers. Second, we present an improved precomputation algorithm. Our new precomputation algorithm is parallelisable, in contrast to Courtois' algorithm, and it is more efficient even when running sequentially. Third, we demonstrate the improved efficiency of our new algorithm by applying it to the key stream generator E0 from the Bluetooth standard. In this case, we get a theoretical speedup by a factor of about 8, even without any parallelism. This improves the fastest attack known. Practical tests confirm the advantage of our new precomputation algorithm for the test cases considered.

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Fast Correlation Attacks Based on Turbo Code Techniques

Cited by 62 publications

References 15 publications

Improved Fast Correlation Attacks Using Parity-Check Equations of Weight 4 and 5

Improved Fast Correlation Attacks Using Parity-Check Equations of Weight 4 and 5

Propagation Characteristics and Correlation-Immunity of Highly Nonlinear Boolean Functions

Improving Fast Algebraic Attacks

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