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Improved Generic Attacks on Unbalanced Feistel Schemes with Expanding Functions [chapter]

Emmanuel Volte, Valérie Nachef, Jacques Patarin
2010 Lecture Notes in Computer Science  
Generic" Unbalanced Feistel Schemes with Expanding Functions are Unbalanced Feistel Schemes with truly random internal round functions from n bits to (k − 1)n bits with k ≥ 3.  ...  As pointed in [7] and [18], there are surprisingly much more possibilities for these attacks than for generic balanced Feistel schemes or generic unbalanced Feistel schemes with contracting functions.  ...  Generic attacks on Unbalanced Feistel Schemes with expanding functions is the theme of this paper.  ... 
doi:10.1007/978-3-642-17373-8_6 fatcat:nuvyb7gwsrhcpiu226ehsef4cq

Generic Attacks on Unbalanced Feistel Schemes with Expanding Functions [chapter]

Jacques Patarin, Valérie Nachef, Côme Berbain
Advances in Cryptology – ASIACRYPT 2007  
Unbalanced Feistel schemes with expanding functions are used to construct pseudo-random permutations from kn bits to kn bits by using random functions from n bits to (k − 1)n bits.  ...  At each round, all the bits except n bits are changed by using a function that depends only on these n bits.  ...  Therefore here we have: ϕ = 4, a = 2, n I = 4, n S = 5, n X = 5, where ϕ denotes the number of points linked with the equalitites, a denotes the number of equations in X between the indices 1 and 3, n  ... 
doi:10.1007/978-3-540-76900-2_20 dblp:conf/asiacrypt/PatarinNB07 fatcat:o4klgbjyvfc4nlwqptmz63lcky

Generic Attacks on Unbalanced Feistel Schemes with Contracting Functions [chapter]

Jacques Patarin, Valérie Nachef, Côme Berbain
2006 Lecture Notes in Computer Science  
In this paper, we describe generic attacks on unbalanced Feistel schemes with contracting functions.  ...  When d ≥ 2k, we also describe some attacks on schemes with generators, (i.e. schemes where the d pseudo-random functions are generated) and where more than one permutation is required.  ...  There are much more papers on classical Feistel schemes and even attacks on expanding unbalanced Feistel schemes have been more studied than attacks on contracting unbalanced Feistel schemes.  ... 
doi:10.1007/11935230_26 fatcat:sj6jooosnnd73frvcjrlkhmjqe

Quantum Generic Attacks on Feistel Schemes [article]

Hong Wang, Zhi Ma
2017 arXiv   pre-print
Furthermore, the method presented in this paper can also be used to consider unbalanced Feistel schemes with expanding functions.  ...  In this paper, efficient quantum algorithms for distinguishing classical 3,4-round and unbalanced Feistel scheme with contracting functions from random permutation are proposed.  ...  Unbalanced Feistel Scheme: An unbalanced FS G d k with contracting functions is a FS with d rounds.  ... 
arXiv:1010.1624v3 fatcat:txbfn2fp7bcjfkrqa4cs5mxavy

Differential Attacks on Generalized Feistel Schemes [chapter]

Valérie Nachef, Emmanuel Volte, Jacques Patarin
2013 Lecture Notes in Computer Science  
While generic attacks on classical Feistel schemes and unbalanced Feistel schemes have been studied a lot, generic attacks on several generalized Feistel schemes like type-1, type-2 and type-3 and Alternating  ...  Also, Type-1 and Type-2 Feistel schemes are respectively used in the construction of the hash functions Lesamnta and SHAvite − 3512.  ...  Improved Generic Attacks on Unbalanced Feistel Schemes with Expanding Functions.  ... 
doi:10.1007/978-3-319-02937-5_1 fatcat:lfcgsb4divau5bupccyxfn3hji

On Generalized Feistel Networks [chapter]

Viet Tung Hoang, Phillip Rogaway
2010 Lecture Notes in Computer Science  
We prove beyond-birthday-bound security for most of the well-known types of generalized Feistel networks: (1) unbalanced Feistel networks, where the n-bit to m-bit round functions may have n ̸ = m; (2)  ...  Using a unified analytic framework, we show that, in any of these settings, for any ε > 0, with enough rounds, the subject scheme can tolerate CCA attacks of up to q ∼ N 1−ε adversarial queries, where  ...  Generic attacks on unbalancedFeistel schemes with expanding functions. ASIACRYPT 2007, LNCS 4833, Springer, pp. 325-341, 2007. 29. PCI Security Standards Council.  ... 
doi:10.1007/978-3-642-14623-7_33 fatcat:qnaznn3t7zflhinr75k7kr4u54

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

Jian Guo, Jérémy Jean, Ivica Nikolic, Yu Sasaki
2017 IACR Transactions on Symmetric Cryptology  
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 the general case of expanding Feistels with arbitrary keyless round functions (we denote them as expanding Feistel-F), we show an attack on 4d − 3 rounds.  ... 
doi:10.13154/tosc.v2016.i2.307-337 dblp:journals/tosc/GuoJNS16 fatcat:ubvkblfxovhmjlk662xbkq7kwi

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

Jian Guo, Jérémy Jean, Ivica Nikolic, Yu Sasaki
2017 IACR Transactions on Symmetric Cryptology  
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 the general case of expanding Feistels with arbitrary keyless round functions (we denote them as expanding Feistel-F), we show an attack on 4d − 3 rounds.  ... 
doi:10.46586/tosc.v2016.i2.307-337 fatcat:enlbfiobojhyxnqrx4n72sjsxm

Building Secure Block Ciphers on Generic Attacks Assumptions [chapter]

Jacques Patarin, Yannick Seurin
2009 Lecture Notes in Computer Science  
Our design strategy enables to give a reductionist security proof for the primitive based on plausible assumptions regarding the complexity of the best distinguishing attacks on random Feistel schemes  ...  Our construction strategy leads to a large expanded key size, though still usable in practice (around 1 MB).  ...  Generic Attacks on Feistel Schemes Generic attacks on Ψ (3) and Ψ (4) .  ... 
doi:10.1007/978-3-642-04159-4_5 fatcat:lbxt5nkisza3paoaizw3wpuozu

Permutation Generators Based on Unbalanced Feistel Network: Analysis of the Conditions of Pseudorandomness [article]

Kwangsu Lee
2017 arXiv   pre-print
One way to construct block ciphers with large input-output size is to use an unbalanced Feistel network that is the generalization of a previous Feistel network.  ...  There have been little research on unbalanced Feistel networks and previous work was about some particular structures of unbalanced Feistel networks.  ...  Therefore, much research is needed on unbalanced Feistel networks suitable for implementing block ciphers with large input-output size.  ... 
arXiv:1703.08306v1 fatcat:ejrsugr5orhsrcr3p7cjnyp7cm

Elastic block ciphers: method, security and instantiations

Debra L. Cook, Moti Yung, Angelos D. Keromytis
2009 International Journal of Information Security  
recovery attacks.  ...  Our method uses the round function of an existing block cipher as a black box and inserts it into a substitution-permutation network.  ...  Whereas, an unbalanced Feistel network places no restriction on the length of y in relation to b. 5.  ... 
doi:10.1007/s10207-008-0075-9 fatcat:h7rm2xvek5e6lmijbrrlqkfhfe

FNR: Arbitrary Length Small Domain Block Cipher Proposal [chapter]

Sashank Dara, Scott Fluhrer
2014 Lecture Notes in Computer Science  
In addition to the classic Feistel networks, Naor and Reingold propose usage of Pair-wise independent permutation (PwIP) functions based on Galois Field GF(2 n ).  ...  We propose a practical flexible (or arbitrary) length small domain block cipher, FNR encryption scheme. FNR denotes Flexible Naor and Reingold.  ...  a Feistel Network based scheme relies on security of underlying PRF (i.e round function) [6] .  ... 
doi:10.1007/978-3-319-12060-7_10 fatcat:boihyihjs5b55llhnm4e4ijudq

Generic Attacks on Misty Schemes [chapter]

Valérie Nachef, Jacques Patarin, Joana Treger
2010 Lecture Notes in Computer Science  
In this paper we describe the best known "generic" attacks on Misty schemes, i.e. attacks when the internal permutations do not have special properties, or are randomly chosen.  ...  Misty schemes are important from a practical point of view since for example, the Kasumi algorithm based on Misty schemes has been adopted as the standard block cipher in the third generation mobile systems  ...  For unbalanced Feistel schemes with expanding functions the best known generic attacks are "2-point", "4-point", or rectangle attacks with 6, 8, 10,... points (see [14] ).  ... 
doi:10.1007/978-3-642-14712-8_14 fatcat:bw62sbzdovhgxlpvqgjv3gulrq

On Lai–Massey and quasi-Feistel ciphers

Aaram Yun, Je Hong Park, Jooyoung Lee
2010 Designs, Codes and Cryptography  
Also, we prove the birthday security of (2b−1)and (3b−2)-round unbalanced quasi-Feistel ciphers with b branches against CPA and CPCA attacks, respectively.  ...  We show that most of the works on the Feistel cipher can be naturally extended to the quasi-Feistel cipher.  ...  In [17] , Patarin et al. gave generic attacks for unbalanced Feistel ciphers with contracting functions.  ... 
doi:10.1007/s10623-010-9386-8 fatcat:ar73otms5rdslavxcadi7kbu5m

Page 7263 of Mathematical Reviews Vol. , Issue 99j [page]

1999 Mathematical Reviews  
7263 99j:94051 94A60 Jutla, Charanjit S. (1-IBM; Yorktown Heights, NY) Generalized birthday attacks on unbalanced Feistel networks.  ...  We show a new generalized birthday attack on F, with d < 3k —3. With 2°~'” chosen plain- texts an adversary can distinguish F, (with d = 3k —3) from a random permutation with high probability.  ... 
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