Abstract
We examine a generalization of the concept of Feistel networks, which we call Unbalanced Feistel Networks (UFNs). Like conventional Feistel networks, UFNs consist of a series of rounds in which one part of the block operates on the rest of the block. However, in a UFN the two parts need not be of equal size. Removing this limitation on Feistel networks has interesting implications for designing ciphers secure against linear and differential attacks. We describe UFNs and a terminology for discussing their properties, present and analyze some UFN constructions, and make some initial observations about their security.
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References
R. Anderson and E. Biham, “Two Practical and Provably Secure Block Ciphers: BEAR and LION,” Proceedings of the Cambridge Algorithms Workshop, 1996, to appear.
C.M. Adams and S.E. Tavares, “Designing S-boxes for Ciphers Resistant to Differential Cryptanalysis,” Proceedings of the 3rd Symposium on State and Progress of Research in Cryptography, Rome, Italy, 15–16 Feb 1993, pp. 181–190.
I. Ben-Aroya and E. Biham, “Differential Cryptanalysis of Lucifer,” Advances in Cryptology —CRYPTO '93 Proceedings, Spinger-Verlag, 1994.
E. Biham, “On Matsui's Linear Cryptanalysis,” Advances in Cryptology — EUROCRYPT '94 Proceedings, Springer-Verlag, 1995, to appear.
G. Bhattacharyya and R. Johnson, Statistical Concepts and Methods, John Wiley and Sons, 1977.
E. Biham and A. Shamir, Differential Cryptanalysis of the Data Encryption Standard, Springer-Verlag, 1993.
M. Blaze and B. Schneier, “The MacGuffin Block Cipher Algorithm,” Fast Software Encryption, Second International Workshop Proceedings, Springer-Verlag, 1995, pp. 97–110.
L. Brown, M. Kwan, J. Pieprzyk, and J. Seberry, “Improving Resistance to Differential Cryptanalysis and the Redesign of LOKI,” Advances in Cryptology — ASIACRYPT '91 Proceedings, Springer-Verlag, 1993, pp. 36–50.
G. Carter, E. Dawson, and L. Nielsen, “DESV: A Latin Square Variation of DES,” Proceedings of the Workshop on Selected Areas in Cryptography, Ottawa, Canada, 1995.
J. Daemen, R. Govaerts, and J. Vandewalle, “A New Approach to Block Cipher Design,” Fast Software Encryption, Cambridge Security Workshop Proceedings, Springer-Verlag, 1994, pp. 18–32.
J. Daemen, “Cipher and Hash Function Design,” Ph.D Thesis, Katholieke Universiteit Leuven, Mar 95.
H. Feistel, “Cryptography and Computer Privacy,” Scientific American, v. 228, n. 5, May 1973, pp. 15–23.
GOST, Gosudarstvennyi Standard 28147-89, “Cryptographic Protection for Data Processing Systems,” Government Committee of the USSR for Standards, 1989.
C. Harpes, G. Kramer, J. Massey, “A Generalization of Linear Cryptanalysis and the Applicability f Matsui's Piling-up Lemma,” Advances in Cryptology — EUROCRYPT '95 Proceedings, Springer, 1995, pp. 24–38.
L.R. Knudsen, “Iterative Characteristics of DES and s2 DES,” Advances in Cryptology — CRYPTO '92, Springer-Verlag, 1993, pp. 497–511.
L.R. Knudsen, “Block Ciphers — Analysis, Design, Applications,” Ph.D. dissertation, Aarhus University, Nov 1994.
L.R. Knudsen, “Practically Secure Feistel Ciphers,” Fast Software Encryption, Cambridge Security Workshop Proceedings, Springer-Verlag, 1994, pp. 211–221.
L.R. Knudsen, personal communication.
R.C. Merkle, “Fast Software Encryption Functions,” Advances in Cryptology — CRYPTO '90 Proceedings, Springer-Verlag, 1991, pp. 476–501.
National Bureau of Standards, NBS FIPS PUB 46, “Data Encryption Standard,” National Bureau of Standards, U.S. Department of Commerce, Jan 1977.
National Institute of Standards and Technology, NIST FIPS PUB 180, “Secure Hash Standard,” U.S. Department of Commerce, May 93.
K. Nyberg, “Perfect Nonlinear S-boxes,” Advances in Cryptology — EUROCRYPT '91 Proceedings, Springer-Verlag, 1991, pp. 378–386.
K. Nyberg, “On the Construction of Highly Nonlinear Permutations,” Advances in Cryptology — EUROCRYPT '92 Proceedings, Springer-Verlag, 1993, pp. 92–98.
K. Nyberg, “Differentially Uniform Mappings for Cryptography,” Advances in Cryptology — EUROCRYPT '93 Proceedings, Springer-Verlag, 1994, pp. 55–64.
K. Nyberg and L.R. Knudsen, “Provable Security Against Differential Cryptanalysis,” Journal of Cryptology, v. 8, n. 1, 1995, pp. 27–37.
L. O'Connor, “Enumerating Nondegenerate Permutations,” Advances in Cryptology — EUROCRYPT '93 Proceedings, Springer-Verlag, 1994, pp. 368–377.
L. O'Connor, “On the Distribution of Characteristics in Bijective Mappings,” Advances in Cryptology — EUROCRYPT '93 Proceedings, Springer-Verlag, 1994, pp. 360–370.
L. O'Connor, “On the Distribution of Characteristics in Composite Permutations,” Advances in Cryptology — CRYPTO '93 Proceedings, Springer-Verlag, 1994, pp. 403–412.
B. Preneel and V. Rijmen, “Cryptanalysis of MacGuffin,” Fast Software Encryption, Second International Workshop Proceedings, Springer-Verlag, 1995, pp. 353–358.
Research and Development in Advanced Communication Technologies in Europe, RIPE Integrity Primitives: Final Report of RACE Integrity Primitives Evaluation (R1040), RACE, June 1992.
R.L. Rivest, “The MD4 Message Digest Algorithm,” Advances in Cryptology — CRYPTO '90 Proceedings, Springer-Verlag, 1991, pp. 303–311.
R.L. Rivest, “The MD5 Message Digest Algorithm,” RFC 1321, Apr 1992.
R.L. Rivest, “The RC5 Encryption Algorithm,” Fast Software Encryption, Second International Workshop Proceedings, Springer-Verlag, 1995, pp. 86–96.
I. Schaumuller-Bichl, “On the Design and Analysis of New Cipher Systems Related to the DES,” Technical Report, Linz University, 1983.
B. Schneier, Applied Cryptography, Second Edition, John Wiley & Sons, 1996.
B. Schneier, “Description of a New Variable-Length Key, 64-Bit Block Cipher (Blowfish),” Fast Software Encryption, Cambridge Security Workshop Proceedings, Springer-Verlag, 1994, pp. 191–204.
C.E. Shannon, “Communication Theory of Secrecy Systems,” Bell Systems Technical Journal, v. 27, n. 4, 1948, pp. 379–423.
A. Shimizu and S. Miyaguchi, “Fast Data Encipherment Algorithm FEAL,” Advances in Cryptology — EUROCRYPT '87 Proceedings, Springer-Verlag, 1988, pp. 267–278.
S. Vaudenay, “On the Weak Keys in Blowfish,” Proceedings of the Cambridge Algorithms Workshop, 1996, to appear.
D. Wagner, personal communication.
R.S. Winternitz, “Producing One-Way Hash Functions from DES,” Advances in Cryptology: Proceedings of Crypto 83, Plenum Press, 1984, pp. 203–207.
Y. Zheng, J. Pieprzyk, and J. Seberry, “HAVAL — A One-Way Hashing Algorithm with Variable Length of Output,” Advances in Cryptology — AUSCRYPT '92 Proceedings, Springer-Verlag, 1993, pp. 83–104
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Schneier, B., Kelsey, J. (1996). Unbalanced Feistel networks and block cipher design. In: Gollmann, D. (eds) Fast Software Encryption. FSE 1996. Lecture Notes in Computer Science, vol 1039. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-60865-6_49
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DOI: https://doi.org/10.1007/3-540-60865-6_49
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