Suzan K. Langford, Martin E. Hellman, Differential-Linear Cryptanalysis, Advances in Cryptology, proceedings of CRYPTO '94, Lecture Notes in Computer Science 839, pp. 17--25, 1994.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....and runs in time about 3,500 encryptions of six round DES, which can be done in a few seconds on a PC. 2 There are possible variations of the above attack, which are listed in Table 3. It should be noted that the linear attack combined with differential techniques by Hellman and Langford [4] exploits the same phenomenon as in our attack, but the two attacks are different. Finally we note that in [10] Preneel et al. considered, what they call reduced exors, in differential attacks on the DES in CFB mode. The reduced exors have some resemblance with partial differentials. 5.2 Higher ....

M. E. Hellman and S. K. Langford. Differential--linear cryptanalysis. In Y. G. Desmedt, editor, Advances in Cryptology - Proc. Crypto'94, LNCS 839, pages 26--39. Springer Verlag, 1994.

.... introduced an iterated block cipher known as Proposed Encryption Standard (PES) 2] The same authors, joined by Murphy, proposed a modification of PES called Improved PES (IPES) 3] which improves the security of the original algorithm against differential analysis and truncated differentials [4 6]. In 1992, IPES was commercialized and was renamed the International Data Encryption Algorithm (IDEA) Some believe that, to date, the algorithm is the best and the most secure block algorithm available to the public [7] Although IDEA involves only simple 16 bit operations, software ....

M. Hellman and S. Langford, "Differential-linear cryptanalysis," in Advances in Cryptology, Proceedings of Eurocrypt 1994, pp. 26--36, 1994.

.... the nature of provable security to the two cryptanalysis methods (an elusive goal ) There have been discussions of the similarities of concepts between the two attacks [18] 19] and the analysis of the combination of the attacks into what is referred to as linear differential cryptanalysis [20]. Several refinements to the cryptanalyses have attempted to improve the attacks for some circumstances. Truncated differential cryptanalysis [21] proposes the exploitation of differences at the cipher output where only some of the ciphertext bits have their differences predicted. Higher order ....

M. Hellman and S. Langford, "Differential-Linear Cryptanalysis", Advances in Cryptology - CRYPTO '94 (Lecture Notes in Computer Science no. 839), Springer-Verlag, pp. 26-39, 1994.

....attack of the previous example, saving a factor of 2 20 in data. Moreover, our observation helps to turn differential attacks into much more desirable ciphertext only attacks, with modest increase in data. Our efficient conversion method applies also for the combined differential linear attacks [16], which can be converted into efficient known plaintext attacks. This paper is organized as follows: In section 2 we review the principles of differential cryptanalysis. In section 3 we outline the principles of our method. Then, we demonstrate its applicability for various ciphers; we start by ....

....In the 90 s two powerful methods of cryptanalysis were developed in attempt to break DES: differential cryptanalysis [1] and linear cryptanalysis [18] The first attack uses 2 47 chosen plaintexts, the second uses 2 43 known plaintexts. A mixed differential linear approach was developed in [16] and successfully demonstrated on DES reduced to eight rounds. This combined approach starts as a differential attack for four rounds, preserving parity of particular bit subsets, which are then used by linear relations for the last four rounds. Their attack is a chosen plaintext attack with about ....

[Article contains additional citation context not shown here]

S. K. Langford, M. E. Hellman, Differential-Linear Cryptanalysis, Lecture Notes in Computer Science 839, Advances in Cryptology -- CRYPTO'94, pp.17--25, Springer-Verlag, 1994.

....part we consider the security of RC6 with regards to differential cryptanalysis [1] Then we consider linear cryptanalysis [22] and its application to RC6. Finally in the last two parts we will briefly address issues related to the key schedule and the attack of differential linear cryptanalysis [20]. To facilitate our analysis we make the simple observation that if we were to drop the fixed rotation by lg w bits (FR) from RC6 along with the quadratic function f(x) x(2x 1) i.e. replacing it with the identity function f(x) x) then the resulting cipher would be very similar to how we ....

.... 2r 4g for s = 1 to v do f A = S[i] S[i] A B) 3 B = L[j] L[j] A B) A B) i = i 1) mod (2r 4) j = j 1) mod c g 61 Part IV Other Attacks 13 Differential Linear Cryptanalysis Differential linear cryptanalysis was introduced by Langford and Hellman at Crypto 94 [20]. This very elegant attack uses a differential to predict the difference between two texts part way through the encryption. From knowledge of this difference, it is possible to use a linear approximation starting at this later stage during the encryption. Sometimes, with a sufficiently good linear ....

[Article contains additional citation context not shown here]

S.K. Langford and M.E. Hellman. Differential-linear cryptanalysis. In Y.G. Desmedt, editor, Advances in Cryptology --- Crypto '94, volume 839 of Lecture Notes in Computer Science, pages 17--25, 1994. Springer Verlag.

....may have a similar vulnerability. Different definitions and extensions of differentials have been used against different ciphers (the exclusive or definition of Biham and Shamir [1] the group inverse definition of Lai and Massey [6] the linear differential cryptanalysis of Langford and Hellman [7], truncated and higher order differentials [4] and it is reasonable to expect that an appropriate definition of a differential could target LFSR counter mode. The ATM Security Specification includes a counter mode that is a hybrid of the integer and LFSR modes [3] In that specification, the ....

Langford, S., and Hellman, M. "Differential-Linear Cryptanalysis", Proceedings of CRYPTO '94: Advances in Cryptology, Springer-Verlag, 1994.

....methods can also be applicable directly without changing the location of 8 DES like of s 5 DES to enhance the security of s 5 DES against the key exhaustuve search attack. Finally, further works are left as open problems to evaluate that s 5 DES is resistant against differentiallinear attack [15] and multiple linear attack [16] ....

S.K. Langford and M.E. Hellman, "Differential-Linear Cryptanalysis", Advances in CryptologyCrypto '94, Springer-Verlag, pp.17--25, 1994.

.... introduced an iterated block cipher known as Proposed Encryption Standard (PES) 2] The same authors, joined by Murphy, proposed a modification of PES called Improved PES (IPES) 3] which improves the security of the original algorithm against differential analysis and truncated differentials [4, 5, 6]. In 1992, IPES was commercialized and was renamed the International Data Encryption Algorithm (IDEA) Some believe that, to date, the algorithm is the best and the most secure block algorithm available to the public [7] Although IDEA involves only simple 16 bit operations, software ....

M. Hellman and S. Langford, "Differential--linear cryptanalysis," in Advances in Cryptology, Proceedings of Eurocrypt 1994, pp. 26--36, 1994.

....with its own most useful partitioning. We are not aware of any general way to partition F s inputs and outputs to facilitate such attacks. 8.4. 5 Differential linear Cryptanalysis Differential linear cryptanalysis uses a combination of techniques from both differential and linear cryptanalysis [LH94]. Due to the need to cover the last part of the cipher with two copies of a linear characteristic, the bias of the linear characteristic is likely to be extremely small unless the linear portion of the attack is confined to just three or four rounds. The available linear characteristics for ....

S. Langford and M. Hellman, "DifferentialLinear Cryptanalysis," Advances in Cryptology --- CRYPTO '94 Proceedings, SpringerVerlag, 1994, pp. 17--26.

.... key bits [Kn93] XWKRU# RDQ DHPHQ KDSWHU####3URSDJDWLRQ#DQG RUUHODWLRQ QQH[#WR# (6 3URSRVDO#5LMQGDHO DWH# ######## 3DJH# ## ## Later, Martin Hellman and Susan Langford published an attack on an 8 round variant of DES that combines the mechanisms of differential and linear cryptanalysis [HeLa94]. In their attack they apply plaintext pairs with a specific difference that propagates with prop ratio 1 to a certain difference in the intermediate state after 3 rounds confined to a subset of its bits. Then a 3round linear trail is constructed between the output of round 7 and the input of ....

M. Hellman and S. Langford, Differential-Linear Cryptanalysis, in Advances in Cryptology, Proc. Crypto'94, LNCS~839, Y. Desmedt, Ed., Springer-Verlag, 1994, pp. 26-39.

....et al. 1,2] It seems not easy to systematically find some impossible events in block ciphers based on the SP network. Thus the applicability of this attack to CRYPTON should be further investigated in the future. Other variants of differential attacks, such as the differential linear attack [9] and the boomerang attack (differential differential style attack) 24] don t appear to better work on CRYPTON than the basic differential attack. There are also several variants or generalizations of linear cryptanalysis. These include linear cryptanalysis using non linear approximations [19] ....

M.Hellman and S.Langford, Differential-linear cryptanalysis, In Advances in Cryptology-CRYPTO'94, LNCS 839, Springer-Verlag, 1994, pp.26-39.

.... modulo 2 16 , which will be denoted as A Gamma B (mod 2 16 ) A Gamma B (4) 3 The Attack In the following we make use of some recent cryptanalytic tools, namely linear and differential cryptanalysis, for which we refer the reader to [3, 4, 5] and some derivate methods as described in [6, 11]. 3.1 Outline Our main attack finds the two subkeys Z (3) 5 and Z (1) 4 or their additional inverses modulo 2 16 1. In this attack we use the following equation (p 3 fi Z (3) 5 ) 0] Phi (p 3 fi Z (3) 5 ) 0] r 0 3 [0] 5) In Section 3.2 we will show, that we can compute p 3 (p ....

....over all p 2 : r 0 2 [0] 0: 13) Furthermore based on experimental results, we found that for all but 26 of the 2 16 possible values of Z (2) 5 there is a i for which (13) holds with a bias 0:25. Note that using (13) makes our method different from the differential linear one, used in [6]. There a linear approximation was used, that either had to hold for both texts forming the plaintext pair or for none. Using such an approximation with probability p would cause an approximation with probability p 2 (1 Gamma p) 2 for the differential case and therefore limits the ....

M. Hellman and S. Langford, Differential-Linear Cryptanalysis, in Advances in Cryptology, Proc. Crypto '94, LNCS 839, Y. Desmedt, Ed., Springer-Verlag, 1994, pp. 26--36.

....attack of the previous example, saving a factor of 2 20 in data. Moreover, our observation helps to turn differential attacks into much more desirable ciphertext only attacks, with modest increase in data. Our efficient conversion method applies also for the combined differential linear attacks [13], which can be converted into efficient known plaintext attacks. This paper is organized as follows: In section 3 we outline the principles of our method. Then, we demonstrate its applicability for various ciphers; we start by presenting a new differential attack on Madryga [14, 21] with only ....

....In the 90 s two powerful methods of cryptanalysis were developed in attempt to break DES: differential cryptanalysis [1] and linear cryptanalysis [15] The first attack uses 2 47 chosen plaintexts, the second uses 2 43 known plaintexts. A mixed differential linear approach was developed in [13] and successfully demonstrated on DES reduced to eight rounds. This combined approach starts as a differential attack for four rounds, preserving parity of particular bit subsets, which are then used by linear relations for the last four rounds. Their attack is a chosen plaintext attack with about ....

[Article contains additional citation context not shown here]

S. K. Langford, M. E. Hellman, Differential-Linear Cryptanalysis, Lecture Notes in Computer Science 839, Advances in Cryptology -- CRYPTO'94, pp.17--25, Springer-Verlag, 1994.

....attack and has been shown to effective in an attack on FEAL 8 [63] Meanwhile, Harpes et al. 56] have considered a generalization of linear approximations, input output sums, and their general applicability. Yet another intriguing development is that of linear differential cryptanalysis [85] which provides a fusion of the techniques used in both linear and differential cryptanalysis. Interestingly several researchers have highlighted a duality between linear and differential cryptanalysis [103] This duality is also exhibited during the design of techniques to construct good ....

....Block Ciphers DES, requiring a sample size of 2 40 known plaintext. An improved version of the Davies attack due to Biham and Biryukov has been presented [13] and allows an attack on the full DES which requires 2 50 known plaintexts. Finally we report some recent work by Hellman and Langford [85] incorporating techniques due to Biham and Shamir into a linear cryptanalytic attack. This converts the attack into a chosen plaintext attack but enables a great reduction in the number of chosen plaintext ciphertext pairs from the 5000 required for the attack due to Biham and Shamir on eight ....

[Article contains additional citation context not shown here]

S.K. Langford and M.E. Hellman. Differential-linear cryptanalysis. In Y.G. Desmedt, editor, Advances in Cryptology --- Crypto '94, volume 839 of Lecture Notes in Computer Science, pages 17--25, New York, 1994. Springer Verlag. REFERENCES 59

....The technique of linear cryptanalysis [7] is now well known. Most dramatically it has provided the first experimental (though barely practical) compromise [8] of the Data Encryption Standard DES [9] In addition to some theoretical and practical enhancements or extensions to linear cryptanalysis [4, 6, 11] it is natural to consider whether the linear approximations on which linear cryptanalysis relies can be replaced with non linear approximations. Since there are far more non linear approximations than linear approximations, it seems fair to say that by opening ourselves to their use, we might ....

S.K. Langford and M.E. Hellman. Differential-linear cryptanalysis. In Y.G. Desmedt, editor, Advances in Cryptology --- Crypto '94, Lecture Notes in Computer Science 839, Springer Verlag (1994), 17--25.

....is closely related to many other ideas that have previously occurred in the literature. As a result, there are many different ways to think about the boomerang attack. In this section, we will try to survey the possibilities. The boomerang attack is related to the differential linear attack of [HL94]. In a differential linear attack, one covers E 0 with a truncated differential Delta Delta , covers E Gamma1 1 with a linear approximation Gamma Gamma , and finally covers E 1 with a second approximation Gamma Gamma ; there is also the additional requirement that ....

M. Hellman and S. Langford., "Differential--linear cryptanalysis," CRYPTO'94, Springer-Verlag LNCS 839, pages 26--39. Springer Verlag, 1994.

....that the output list contains only the right class. The conditional success probability p GLCjk (1: r) is the probability of this event when the key K (1: r) k (1: r) Matsui considers in [Mat86] an improvement of linear cryptanalysis similar to list decoding of error detecting codes [LH86]. Applied to our generalization, this improvement consists of trying out all keys in all equivalence classes in order of decreasing apparent imbalance jc[ k] Gamma N 2 j until the true key is found. The efficiency of such an algorithm can be measured by the average run time, or by the ....

Susan K. Langford and Martin E. Hellman. Differential-linear cryptanalysis. In Advances in Cryptology -- Crypto'94, Lecture Notes in Computer Science No. 839, pages 17--25. Springer, 1986.

....and runs in time about 3,500 encryptions of six round DES, which can be done in a few seconds on a PC. 2 There are possible variations of the above attack, which are listed in Table 2. It should be noted that the linear attack combined with differential techniques by Hellman and Langford [4] exploits the same phenomenon as in our attack, but the two attacks are different. Finally we note that in [10] Preneel et al. considered, what they call reduced exors, in differential attacks on the DES in CFB mode. The reduced exors have some resemblance with truncated differentials. No. of ....

M. E. Hellman and S. K. Langford. Differential--linear cryptanalysis. In Y. G. Desmedt, editor, Advances in Cryptology - Proc. Crypto'94, LNCS 839, pages 26--39. Springer Verlag, 1994.

....reduce the number of rounds in order to get maximal performance. CAST [AT95] and SAFER [M94] can be seen as attempts in this direction. The lurking danger is that a small number of rounds makes a whole range of new attacks possible, e.g. the differential linear attack on eight rounds of the DES [LH94], truncated differentials in SAFER [K95, K96] and imbalance of the round function in CAST [RP95] We believe SHARK is resistant against these attacks. In Sect. 2 we explain our design strategy and select components for SHARK. Section 3 gives some cryptanalytic benchmarks. In Sect. 4 we make ....

S.K. Langford, M.E. Hellman, "Differential-linear cryptanalysis," Advances in Cryptology, Proc. Crypto'94, LNCS 839, Y. Desmedt, Ed., Springer-Verlag, 1994, pp. 17--25.

....the key is changed to a related key. Related key cryptanalysis[3] or differential related key cryptanalysis[7] might be applied with DFA in such cases. We expect that linear cryptanalysis[12] can also be combined with DFA in some cases (in a similar way to differential linear cryptanalysis[10]) especially when the identification of the fault position is highly reliable (or when the fault positions might be chosen by the attacker) Variants of DFA attacks can in some cases also derive the keys of modes of operation in which only part of the ciphertext is known to the attacker. This is ....

Susan K. Langford, Martin E. Hellman, Differential-linear cryptanalysis, Lecture Notes in Computer Science, Advances in Cryptology, proceedings of CRYPTO'94, pp. 17--25, 1994.

No context found.

Suzan K. Langford, Martin E. Hellman, Differential-Linear Cryptanalysis, Advances in Cryptology, proceedings of CRYPTO '94, Lecture Notes in Computer Science 839, pp. 17--25, 1994.

No context found.

Suzan K. Langford, Martin E. Hellman, Differential-Linear Cryptanalysis, Advances in Cryptology, proceedings of CRYPTO '94, Lecture Notes in Computer Science 839, pp. 17--25, 1994.

No context found.

M.E. Hellman and S. K. Langford. Differential--linear cryptanalysis. In Y. G. Desmedt, editor, Advances in Cryptology - Proc. Crypto'94, LNCS 839, pages 26--

No context found.

Susan K. Langford and Martin E. Hellman. Differential-linear cryptanalysis. In Advances in Cryptology -- Crypto'94, LNCS 839, pages 17--25. Springer, 1986.

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