Abstract
NLS is a stream cipher which was submitted to the eSTREAM project. A linear distinguishing attack against NLS was presented by Cho and Pieprzyk, which was called Crossword Puzzle (CP) attack. NLSv2 is a tweak version of NLS which aims mainly at avoiding the CP attack. In this paper, a new distinguishing attack against NLSv2 is presented. The attack exploits high correlation amongst neighboring bits of the cipher. The paper first shows that the modular addition preserves pairwise correlations as demonstrated by existence of linear approximations with large biases. Next, it shows how to combine these results with the existence of high correlation between bits 29 and 30 of the S-box to obtain a distinguisher whose bias is around 2− 37. Consequently, we claim that NLSv2 is distinguishable from a random cipher after observing around 274 keystream words.
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Cho, J.Y., Pieprzyk, J.: Algebraic attacks on SOBER-t32 and SOBER-t16 without stuttering. In: Roy, B., Meier, W. (eds.) FSE 2004. LNCS, vol. 3017, pp. 49–64. Springer, Heidelberg (2004)
Cho, J.Y., Pieprzyk, J.: Crossword puzzle attack on NLS. In: Proceedings of Selected Areas in Cryptography - SAC 2006, Montreal, Quebec, Canada (August 2006)
Cho, J.Y., Pieprzyk, J.: Linear distinguishing attack on NLS. In: SASC, workshop (2006), available at http://www.ecrypt.eu.org/stvl/sasc2006/
Hawkes, P., Paddon, M., Rose, G., de Vries, M.W.: Primitive specification for NLS (April 2005), available at http://www.ecrypt.eu.org/stream/nls.html
Hawkes, P., Paddon, M., Rose, G., de Vries, M.W.: Primitive specification for NLSv2. eSTREAM (March 2006), available at http://www.ecrypt.eu.org/stream/nls.html
Matsui, M.: Linear cryptanalysis method for DES cipher. In: Helleseth, T. (ed.) EUROCRYPT 1993. LNCS, vol. 765, pp. 386–397. Springer, Heidelberg (1994)
NIST. SKIPJACK and KEA algorithm specifications (May 1998), available at http://csrc.nist.gov/CryptoToolkit/skipjack/skipjack.pdf
ECRYPT NoE. eSTREAM - the ECRYPT stream cipher project (2005), available at http://www.ecrypt.eu.org/stream/
Nyberg, K., Wallen, J.: Improved linear distinguishers for SNOW 2.0. In: Robshaw, M. (ed.) FSE 2006. LNCS, vol. 4047, pp. 144–162. Springer, Heidelberg (2006)
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Cho, J.Y., Pieprzyk, J. (2007). Multiple Modular Additions and Crossword Puzzle Attack on NLSv2. In: Garay, J.A., Lenstra, A.K., Mambo, M., Peralta, R. (eds) Information Security. ISC 2007. Lecture Notes in Computer Science, vol 4779. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-75496-1_16
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DOI: https://doi.org/10.1007/978-3-540-75496-1_16
Publisher Name: Springer, Berlin, Heidelberg
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