Abstract
This paper describes a linear analysis of Blowfish (a block cipher designed by B. Schneier in 1993), and Khufu (a cipher designed by R.C. Merkle in 1989). The nonlinear cipher components of these ciphers are key dependent, and thus, unknown to unauthorized entities. Nonetheless, we estimate the fraction of user keys that generate weak nonlinear components (namely, with large enough bias). As far as we are aware of this paper reports the first known-plaintext (and ciphertext-only) attacks on these ciphers.
Research funded by FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo) under contract 2005/02102-9.
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References
Biham, E.: On Matsui’s Linear Cryptanalysis. Technion, CS Dept. Technical Report CS0813 (1994)
Biham, E., Biryukov, A., Shamir, A.: Miss-in-the-Middle Attacks on IDEA, Khufu and Khafre. In: Knudsen, L.R. (ed.) FSE 1999. LNCS, vol. 1636, pp. 124–138. Springer, Heidelberg (1999)
Biham, E., Dunkelman, O., Keller, N.: Linear Cryptanalysis of Reduced Round Serpent. In: Matsui, M. (ed.) FSE 2001. LNCS, vol. 2355, pp. 16–27. Springer, Heidelberg (2002)
Biryukov, A.: The Boomerang Attack on 5 and 6-round Reduced AES. In: Dobbertin, H., Rijmen, V., Sowa, A. (eds.) AES 2005. LNCS, vol. 3373, pp. 11–15. Springer, Heidelberg (2005)
Blöcher, U., Dichtl, M.: Problems with the Linear Cryptanalysis of DES using More than One Active S-box per Round. In: Anderson, R. (ed.) FSE 1993. LNCS, vol. 809, pp. 256–274. Springer, Heidelberg (1994)
Brown, L., Pieprzyk, J.: Introducing the New LOKI97 Block Cipher. In: 1st AES Conference, California, USA (Aug. 1998), http://csrc.nist.gov/encryption/aes/
Cheon, J.H., et al.: Improved Impossible Differential Cryptanalysis of Rijndael and Crypton. In: Kim, K.-c. (ed.) ICISC 2001. LNCS, vol. 2288, pp. 39–49. Springer, Heidelberg (2002)
Daemen, J., Govaerts, R., Vandewalle, J.: Weak Keys for IDEA. In: Stinson, D.R. (ed.) CRYPTO 1993. LNCS, vol. 773, pp. 224–231. Springer, Heidelberg (1994)
Daemen, J., Rijmen, V.: The Design of Rijndael – AES – The Advanced Encryption Standard. Springer, Heidelberg (2002)
Gilbert, H., Chauvaud, P.: A Chosen Plaintext Attack of the 16-Round Khufu Cryptosystem. In: Desmedt, Y.G. (ed.) CRYPTO 1994. LNCS, vol. 839, pp. 359–368. Springer, Heidelberg (1994)
Knudsen, L.R.: Weaknesses in LOKI97 (1999), http://csrc.nist.gov/encryption/aes/
Knudsen, L.R., Mathiassen, J.E.: A Chosen-Plaintext Linear Attack on DES. In: Schneier, B. (ed.) FSE 2000. LNCS, vol. 1978, pp. 262–272. Springer, Heidelberg (2001)
Knudsen, L.R., Rijmen, V.: Ciphertext-Only Attack on Akelarre. Cryptologia XXIV(2), 135–147 (2000)
Matsui, M.: Linear Cryptanalysis Method for DES Cipher. In: Helleseth, T. (ed.) EUROCRYPT 1993. LNCS, vol. 765, pp. 386–397. Springer, Heidelberg (1994)
Matsui, M.: On Correlation Between the Order of S-boxes and the Strength of DES. In: De Santis, A. (ed.) EUROCRYPT 1994. LNCS, vol. 950, pp. 366–375. Springer, Heidelberg (1995)
Matsui, M., Yamagishi, A.: A New Method for Known-Plaintext Attack of FEAL Cipher. In: Rueppel, R.A. (ed.) EUROCRYPT 1992. LNCS, vol. 658, pp. 81–91. Springer, Heidelberg (1993)
Merkle, R.C.: Fast Software Encryption Functions. In: Menezes, A., Vanstone, S.A. (eds.) CRYPTO 1990. LNCS, vol. 537, pp. 476–501. Springer, Heidelberg (1991)
NBS, Data Encryption Standard (DES). FIPS PUB 46, Federal Information Processing Standards Publication 46, U.S. Department of Commerce (Jan. 1977)
Rijmen, V.: Cryptanalysis and Design of Iterated Block Ciphers. Dept. Elektrotechniek, Katholieke Universiteit Leuven, Belgium (Oct. 1997)
Rivest, R.L., et al.: The RC6 Block Cipher. In: 1st AES Conference, California, USA (Aug. 1998), http://csrc.nist.gov/encryption/aes/
Schneier, B.: Blowfish–One Year Later. Dr. Dobbs Journal (Sep. 1995)
Schneier, B.: Description of a New Variable-Length Key, 64-Bit Block Cipher (Blowfish). In: Anderson, R. (ed.) FSE 1993. LNCS, vol. 809, pp. 191–204. Springer, Heidelberg (1994)
Selçuk, A.A.: On Bias Estimation in Linear Cryptanalysis. In: Roy, B., Okamoto, E. (eds.) INDOCRYPT 2000. LNCS, vol. 1977, pp. 52–66. Springer, Heidelberg (2000)
Shorin, V.V., Jelezniakov, V.V., Gabidulin, E.M.: Linear and Differential Cryptanalysis of Russian GOST. In: Augot, D. (ed.) Proc. of Workshop on Coding and Cryptography, Jan. 2001, pp. 467–476 (2001)
Vaudenay, S.: On the Weak Keys of Blowfish. Technical Report, Liens - 95- 27, Ecole Normale Superieure
Wagner, D.: The Boomerang Attack. In: Knudsen, L.R. (ed.) FSE 1999. LNCS, vol. 1636, pp. 156–170. Springer, Heidelberg (1999)
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Nakahara, J. (2007). A Linear Analysis of Blowfish and Khufu. In: Dawson, E., Wong, D.S. (eds) Information Security Practice and Experience. ISPEC 2007. Lecture Notes in Computer Science, vol 4464. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-72163-5_3
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DOI: https://doi.org/10.1007/978-3-540-72163-5_3
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