摘要 :
Indeed, the current cryptography suffers from the rise of the computing power of computers and the advent of quantum computers could be the death knell of these algorithms. Therefore, with this paper, we present a new encryption a...
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Indeed, the current cryptography suffers from the rise of the computing power of computers and the advent of quantum computers could be the death knell of these algorithms. Therefore, with this paper, we present a new encryption approach based on chaotic outputs to insure more protection. This approach combines two encryption techniques in addition to random permutation. The first one consists to put in disorder binary data and the second technique is based on conditional logical function. The choice between those two techniques is perfectly random and generated from chaotic outputs. Each process has her own keys which make the encryption more complicated.
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摘要 :
Designing a block cipher or cryptographic permutation can be approached in many different ways. One such approach, popularized by AES, consists in grouping the bits along the S-box boundaries, e.g., in bytes, and in consistently p...
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Designing a block cipher or cryptographic permutation can be approached in many different ways. One such approach, popularized by AES, consists in grouping the bits along the S-box boundaries, e.g., in bytes, and in consistently processing them in these groups. This aligned approach leads to hierarchical structures like superboxes that make it possible to reason about the differential and linear propagation properties using combinatorial arguments. In contrast, an unaligned approach avoids any such grouping in the design of transformations. However, without hierarchical structure, sophisticated computer programs are required to investigate the differential and linear propagation properties of the primitive. In this paper, we formalize this notion of alignment and study four primitives that are exponents of different design strategies. We propose a way to analyze the interactions between the linear and the nonlinear layers w.r.t. the differential and linear propagation, and we use it to systematically compare the four primitives using non-trivial computer experiments. We show that alignment naturally leads to different forms of clustering, e.g., of active bits in boxes, of two-round trails in activity patterns, and of trails in differentials and linear approximations.
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摘要 :
Designing a block cipher or cryptographic permutation can be approached in many different ways. One such approach, popularized by AES, consists in grouping the bits along the S-box boundaries, e.g., in bytes, and in consistently p...
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Designing a block cipher or cryptographic permutation can be approached in many different ways. One such approach, popularized by AES, consists in grouping the bits along the S-box boundaries, e.g., in bytes, and in consistently processing them in these groups. This aligned approach leads to hierarchical structures like superboxes that make it possible to reason about the differential and linear propagation properties using combinatorial arguments. In contrast, an unaligned approach avoids any such grouping in the design of transformations. However, without hierarchical structure, sophisticated computer programs are required to investigate the differential and linear propagation properties of the primitive. In this paper, we formalize this notion of alignment and study four primitives that are exponents of different design strategies. We propose a way to analyze the interactions between the linear and the nonlinear layers w.r.t. the differential and linear propagation, and we use it to systematically compare the four primitives using non-trivial computer experiments. We show that alignment naturally leads to different forms of clustering, e.g., of active bits in boxes, of two-round trails in activity patterns, and of trails in differentials and linear approximations.
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An exact value of round functions collision probability for 3-round Feistel network is derived. The upper bound of algorithm execution complexity for distinguishing Feistel network from a random permutation is given.
摘要 :
An exact value of round functions collision probability for 3-round Feistel network is derived. The upper bound of algorithm execution complexity for distinguishing Feistel network from a random permutation is given.
摘要 :
This paper initiates the study of standard-model assumptions on permutations - or more precisely, on families of permutations indexed by a public seed. We introduce and study the notion of a public-seed pseudorandom permutation (p...
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This paper initiates the study of standard-model assumptions on permutations - or more precisely, on families of permutations indexed by a public seed. We introduce and study the notion of a public-seed pseudorandom permutation (psPRP), which is inspired by the UCE notion by Bellare, Hoeing, and Keelveedhi (CRYPTO '13). It considers a two-stage security game, where the first-stage adversary is known as the source, and is restricted to prevent trivial attacks - the security notion is consequently parameterized by the class of allowable sources. To this end, we define in particular unpredictable and reset-secure sources analogous to similar notions for UCEs. We first study the relationship between psPRPs and UCEs. To start with, we provide efficient constructions of UCEs from psPRPs for both reset-secure and unpredictable sources, thus showing that most applications of the UCE framework admit instantiations from psPRPs. We also show a converse of this statement, namely that the five-round Feistel construction yields a psPRP for reset-secure sources when the round function is built from UCEs for reset-secure sources, hence making psPRP and UCE equivalent notions for such sources. In addition to studying such reductions, we suggest generic instantiations of psPRPs from both block ciphers and (keyless) permutations, and analyze them in ideal models. Also, as an application of our notions, we show that a simple modification of a recent highly-efficient garbling scheme by Bellare et al. (S&P '13) is secure under our psPRP assumption.
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摘要 :
This paper initiates the study of standard-model assumptions on permutations - or more precisely, on families of permutations indexed by a public seed. We introduce and study the notion of a public-seed pseudorandom permutation (p...
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This paper initiates the study of standard-model assumptions on permutations - or more precisely, on families of permutations indexed by a public seed. We introduce and study the notion of a public-seed pseudorandom permutation (psPRP), which is inspired by the UCE notion by Bellare, Hoeing, and Keelveedhi (CRYPTO '13). It considers a two-stage security game, where the first-stage adversary is known as the source, and is restricted to prevent trivial attacks - the security notion is consequently parameterized by the class of allowable sources. To this end, we define in particular unpredictable and reset-secure sources analogous to similar notions for UCEs. We first study the relationship between psPRPs and UCEs. To start with, we provide efficient constructions of UCEs from psPRPs for both reset-secure and unpredictable sources, thus showing that most applications of the UCE framework admit instantiations from psPRPs. We also show a converse of this statement, namely that the five-round Feistel construction yields a psPRP for reset-secure sources when the round function is built from UCEs for reset-secure sources, hence making psPRP and UCE equivalent notions for such sources. In addition to studying such reductions, we suggest generic instantiations of psPRPs from both block ciphers and (keyless) permutations, and analyze them in ideal models. Also, as an application of our notions, we show that a simple modification of a recent highly-efficient garbling scheme by Bellare et al. (S&P '13) is secure under our psPRP assumption.
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At CHES 2010, the new block cipher PRINTCIPHER was presented. In addition to using an xor round key as is common practice for round-based block ciphers, PRINTCIPHER also uses key-dependent permutations. While this seems to make di...
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At CHES 2010, the new block cipher PRINTCIPHER was presented. In addition to using an xor round key as is common practice for round-based block ciphers, PRINTCIPHER also uses key-dependent permutations. While this seems to make differential cryptanalysis difficult due to the unknown bit permutations, we show in this paper that this is not the case. We present two differential attacks that successfully break about half of the rounds of PRINTCIPHER, thereby giving the first cryptanalytic result on the cipher. In addition, one of the attacks is of independent interest, since it uses a mechanism to compute roots of permutations. If an attacker knows the many-round permutation π~r, the algorithm can be used to compute the underlying single-round permutation π. This technique is thus relevant for all iterative ciphers that deploy key-dependent permutations. In the case of PRINTCIPHER, it can be used to show that the linear layer adds little to the security against differential attacks.
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摘要 :
At CHES 2010, the new block cipher PRINTcipher was presented. In addition to using an xor round key as is common practice for round-based block ciphers, PRINTcipher also uses key-dependent permutations. While this seems to make di...
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At CHES 2010, the new block cipher PRINTcipher was presented. In addition to using an xor round key as is common practice for round-based block ciphers, PRINTcipher also uses key-dependent permutations. While this seems to make differential cryptanalysis difficult due to the unknown bit permutations, we show in this paper that this is not the case. We present two differential attacks that successfully break about half of the rounds of PRINTcipher, thereby giving the first cryptanalytic result on the cipher. In addition, one of the attacks is of independent interest, since it uses a mechanism to compute roots of permutations. If an attacker knows the many-round permutation 7rr, the algorithm can be used to compute the underlying single-round permutation n. This technique is thus relevant for all iterative ciphers that deploy key-dependent permutations. In the case of PRINTcipher, it can be used to show that the linear layer adds little to the security against differential attacks.
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In this paper we present a new block cipher over a small finite domain T where ∣T∣ = k is either 2~(16) or 2~(32) . After that we suggest a use of this cipher for enciphering members of arbitrary small finite domains M where M i...
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In this paper we present a new block cipher over a small finite domain T where ∣T∣ = k is either 2~(16) or 2~(32) . After that we suggest a use of this cipher for enciphering members of arbitrary small finite domains M where M is contained in T. With cost of an extra mapping, this method could be further extended for enciphering in arbitrary domain M' where ∣M'∣ = k' ≤ k. At last, in a discussion section we suggest a few interesting usage scenarios for such a cipher as an argument that enciphering with arbitrary small finite domains is a very useful primitive on its own rights, as well as for designing of a higher level protocols.
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