Abstract
In this paper, an improved fast correlation attack on stream ciphers is presented. The proposed technique is based on the construction of an unequal error protecting LDPC code from the LFSR output sequence. The unequal error protection allows to achieve lower bit-error probability for initial bits of the LFSR in compared to the rest of the output bits. We show that constructing the unequal error protecting code has also the advantage of reducing the number of output bits involved in decoding to less than the available keystream output bits. Our decoding approach is based on combination of exhaustive search over a subset of information bits and a soft-decision iterative message passing decoding algorithm. We compare the performance of the proposed algorithm with the recent fast correlation attacks. Our results show that we can reduce the number of bits obtained by exhaustive search in half and still get better performance comparing to recent fast correlation attacks based on iterative decoding algorithm. Using the expected number of parity-check equations of certain weights, we find the lower bound on the number of information bits that needs to be obtained by the exhaustive search without compromising the performance.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Rueppel, R.A.: Analysis and Design of Stream Ciphers. Springer, Heidelberg (1986)
Siegenthaler, T.: Correlation-immunity of nonlinear combining functions for cryptographic applications. IEEE Trans. on Information Theory IT-30, 776–780 (1984)
Meier, W., Staffelbach, O.: Fast correlation attacks on stream ciphers. In: Günther, C.G. (ed.) EUROCRYPT 1988. LNCS, vol. 330, pp. 301–314. Springer, Heidelberg (1988)
Golic, J., Salmasizadeh, M., Clark, A., Khodkar, A., Dawson, E.: Discrete optimisation and fast correlation attacks. In: Proceedings of Cryptography: Policy and Algorithms. International Conference, pp. 186–200 (1996)
Penzhorn, W., Kuhn, G.: Computation of low-weight parity checks for correlation attacks on stream ciphers. In: Proceedings of Cryptography and Coding. 5th IMA Conference, pp. 74–83 (1995)
Chepyzhov, V., Smeets, B.: On a fast correlation attack on certain stream ciphers. In: Davies, D.W. (ed.) EUROCRYPT 1991. LNCS, vol. 547, pp. 176–185. Springer, Heidelberg (1991)
Mihaljevic, M., Golic, J.: A fast iterative algorithm for a shift register initial state reconstruction given the noisy output sequence. In: Seberry, J., Pieprzyk, J.P. (eds.) AUSCRYPT 1990. LNCS, vol. 453, pp. 165–185. Springer, Heidelberg (1990)
Johansson, T., Jonsson, F.: Improved fast correlation attacks on stream ciphers via convolutional codes. In: Stern, J. (ed.) EUROCRYPT 1999. LNCS, vol. 1592, pp. 347–362. Springer, Heidelberg (1999)
Johansson, T., Jonsson, F.: Fast correlation attacks based on turbo code techniques. In: Wiener, M. (ed.) CRYPTO 1999. LNCS, vol. 1666, pp. 181–197. Springer, Heidelberg (1999)
Chepyzhov, V., Johansson, T., Smeets, B.: A simple algorithm for fast correlation attacks on stream ciphers. In: Schneier, B. (ed.) FSE 2000. LNCS, vol. 1978, pp. 181–195. Springer, Heidelberg (2001)
Jonsson, F.: Some results on fast correlation attacks. PhD thesis, Lund University (2002)
Canteaut, A., Trabbia, M.: Improved fast correlation attacks using parity-check equations of weight 4 and 5. In: Preneel, B. (ed.) EUROCRYPT 2000. LNCS, vol. 1807, pp. 573–588. Springer, Heidelberg (2000)
Mihaljevic, M., Fossorier, M., Imai, H.: A low-complexity and high performance algorithm for the fast correlation attack. In: Schneier, B. (ed.) FSE 2000. LNCS, vol. 1978, pp. 196–212. Springer, Heidelberg (2001)
Mihaljevic, M., Fossorier, M., Imai, H.: Fast correlation attack algorithm with list decoding and an application. In: Matsui, M. (ed.) FSE 2001. LNCS, vol. 2355, pp. 196–210. Springer, Heidelberg (2002)
Chose, P., Joux, A., Mitton, M.: Fast correlation attacks: an algorithmic point of view. In: Knudsen, L.R. (ed.) EUROCRYPT 2002. LNCS, vol. 2332, pp. 209–221. Springer, Heidelberg (2002)
Kschischang, F., Frey, B., Loeliger, H.: Factor graphs and the sum-product algorithm. IEEE Trans. on Information Theory 47, 498–519 (2001)
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2004 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Noorkami, M., Fekri, F. (2004). A Fast Correlation Attack via Unequal Error Correcting LDPC Codes. In: Okamoto, T. (eds) Topics in Cryptology – CT-RSA 2004. CT-RSA 2004. Lecture Notes in Computer Science, vol 2964. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-24660-2_5
Download citation
DOI: https://doi.org/10.1007/978-3-540-24660-2_5
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-20996-6
Online ISBN: 978-3-540-24660-2
eBook Packages: Springer Book Archive