Abstract
This paper provides a fresh analysis of the widely-used Common Scrambling Algorithm stream cipher (CSA-SC). Firstly, a new representation of CSA-SC with a state size of only 89 bits is given, a significant reduction from the 103 bit state of a previous CSA-SC representation. Analysis of this 89-bit representation demonstrates that the basis of a previous guess-and-determine attack is flawed. Correcting this flaw increases the complexity of that attack so that it is worse than exhaustive key search. Although that attack is not feasible, the reduced state size of our representation makes it obvious that CSA-SC is vulnerable to several generic attacks, for which feasible parameters are given.
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Simpson, L., Henricksen, M., Yap, WS. (2009). Improved Cryptanalysis of the Common Scrambling Algorithm Stream Cipher. In: Boyd, C., González Nieto, J. (eds) Information Security and Privacy. ACISP 2009. Lecture Notes in Computer Science, vol 5594. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-02620-1_8
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DOI: https://doi.org/10.1007/978-3-642-02620-1_8
Publisher Name: Springer, Berlin, Heidelberg
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