Complementing Feistel Ciphers

Generic Attacks on Classical Feistel Ciphers

Feistel Ciphers ◽

10.1007/978-3-319-49530-9_6 ◽

2017 ◽

pp. 65-73

Author(s):

Valerie Nachef ◽

Jacques Patarin ◽

Emmanuel Volte

Keyword(s):

Generic Attacks ◽

Feistel Ciphers

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Impossible Differential Cryptanalysis on Feistel Ciphers with SP and SPS Round Functions

Applied Cryptography and Network Security - Lecture Notes in Computer Science ◽

10.1007/978-3-642-13708-2_7 ◽

2010 ◽

pp. 105-122 ◽

Cited By ~ 5

Author(s):

Yuechuan Wei ◽

Ping Li ◽

Bing Sun ◽

Chao Li

Keyword(s):

Differential Cryptanalysis ◽

Impossible Differential ◽

Feistel Ciphers ◽

Impossible Differential Cryptanalysis

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Secure key-alternating Feistel ciphers without key schedule

Science China Information Sciences ◽

10.1007/s11432-019-9938-0 ◽

2020 ◽

Vol 64 (1) ◽

Author(s):

Yaobin Shen ◽

Hailun Yan ◽

Lei Wang ◽

Xuejia Lai

Keyword(s):

Key Schedule ◽

Feistel Ciphers

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Information leakage of Feistel ciphers

IEEE Transactions on Information Theory ◽

10.1109/18.904500 ◽

2001 ◽

Vol 47 (1) ◽

pp. 23-35 ◽

Cited By ~ 1

Author(s):

H.M. Heys

Keyword(s):

Information Leakage ◽

Feistel Ciphers

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Meet-in-the-Middle Attacks on Classes of Contracting and Expanding Feistel Constructions

IACR Transactions on Symmetric Cryptology ◽

10.46586/tosc.v2016.i2.307-337 ◽

2017 ◽

pp. 307-337 ◽

Cited By ~ 1

Author(s):

Jian Guo ◽

Jérémy Jean ◽

Ivica Nikolic ◽

Yu Sasaki

Keyword(s):

The State ◽

Linear Functions ◽

Block Length ◽

Nonlinear Functions ◽

Round Function ◽

Generic Attacks ◽

Key Length ◽

Feistel Ciphers

We show generic attacks on unbalanced Feistel ciphers based on the meet-in-the-middle technique. We analyze two general classes of unbalanced Feistel structures, namely contracting Feistels and expanding Feistels. In both of the cases, we consider the practical scenario where the round functions are keyless and known to the adversary. In the case of contracting Feistels with 4 branches, we show attacks on 16 rounds when the key length k (in bits) is as large as the block length n (in bits), and up to 24 rounds when k = 2n. In the case of expanding Feistels, we consider two scenarios: one, where different nonlinear functions without particular structures are used in the round function, and a more practical one, where a single nonlinear is used but different linear functions are introduced in the state update. In the former case, we propose generic attacks on 13 rounds when k = n, and up to 21 rounds when k = 2n. In the latter case, 16 rounds can be attacked for k = n, and 24 rounds for k = 2n.

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