The MISTY1 block cipher has a 64-bit block size, a 128-bit master key, and a total of 8 rounds. It is an ISO international standard, a Japanese CRYPTREC-recommended e-government cipher, and a ...European NESSIE selected cipher. In this study, the authors show another cryptographic weakness of the full MISTY1 cipher: they describe four classes of $2^{90}$290 weak keys of the full MISTY1 cipher for a related-key amplified boomerang attack that has a data complexity of $2^{60.5}$260.5 chosen plaintexts and a time complexity of $2^{87.33}$287.33 encryptions under each class of weak keys. The result shows that the MISTY1 cipher can be distinguishable from an ideal cipher in terms of related-key amplified boomerang cryptanalysis, and users should be very careful when using MISTY1 for a full security in relevant application situations.
Camellia is one of the widely used block ciphers, which has been included in the NESSIE block cipher portfolio and selected as a standard by ISO/IEC. In this study, the authors observe that there ...exist some interesting properties of the FL/FL−1 functions in Camellia. With this observation they derive some weak keys for the cipher, based on which they present the first known 8-round zero-correlation linear distinguisher of Camellia with FL/FL−1 layers. This result shows that the FL/FL−1 layers inserted in Camellia cannot resist zero-correlation linear cryptanalysis effectively for some weak keys since the currently best zero-correlation linear distinguisher for Camellia without FL/FL−1 layers also covers eight rounds. Moreover, by using the novel distinguisher, they launch key recovery attacks on 13-round Camellia-192 and 14-round Camellia-256. To their knowledge, these results are the best for Camellia-192 and Camellia-256 with FL/FL−1 and whitening layers.
Finding Higher Order Differentials of MISTY1 TSUNOO, Yukiyasu; SAITO, Teruo; KAWABATA, Takeshi ...
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences,
2012, Letnik:
E95.A, Številka:
6
Journal Article
Recenzirano
MISTY1 is a 64-bit block cipher that has provable security against differential and linear cryptanalysis. MISTY1 is one of the algorithms selected in the European NESSIE project, and it is ...recommended for Japanese e-Government ciphers by the CRYPTREC project. In this paper, we report on 12th order differentials in 3-round MISTY1 with FL functions and 44th order differentials in 4-round MISTY1 with FL functions both previously unknown. We also report that both data complexity and computational complexity of higher order differential attacks on 6-round MISTY1 with FL functions and 7-round MISTY1 with FL functions using the 46th order differential can be reduced to as much as 1/22 of the previous values by using multiple 44th order differentials simultaneously.
Finding Higher Order Differentials of MISTY1 TSUNOO, Yukiyasu; SAITO, Teruo; KAWABATA, Takeshi ...
IEICE transactions on fundamentals of electronics, communications and computer sciences,
01/2012, Letnik:
E95.A, Številka:
6
Journal Article
Recenzirano
MISTY1 is a 64-bit block cipher that has provable security against differential and linear cryptanalysis. MISTY1 is one of the algorithms selected in the European NESSIE project, and it is ...recommended for Japanese e-Government ciphers by the CRYPTREC project. In this paper, we report on 12th order differentials in 3-round MISTY1 with FL functions and 44th order differentials in 4-round MISTY1 with FL functions both previously unknown. We also report that both data complexity and computational complexity of higher order differential attacks on 6-round MISTY1 with FL functions and 7-round MISTY1 with FL functions using the 46th order differential can be reduced to as much as 1/22 of the previous values by using multiple 44th order differentials simultaneously.
LILI-128 is the stream cipher proposed as a candidate cipher for the New European Schemes for Signatures, Integrity, and Encryption (NESSIE) Project. Some methods of breaking it more efficiently than ...an exhaustive search for its secret key have been found already. The authors propose a new method, which uses shorter bit sequence to break LILI-128 successfully. An attack that can be made with less data can be a more practical threat. With only 2/sup 7/ bits of keystream, this method can break LILI-128 successfully. The efficiency of our attack depends on the memory size. For example, with 2/sup 99.1/ computations, our attack breaks LILI-128, if 2/sup 28.6/-bit memory is available.
MISTY1 is a 64-bit block cipher that has provable security against differential and linear cryptanalysis. MISTY1 is one of the algorithms selected in the European NESSIE project, and it has been ...recommended for Japanese e-Government ciphers by the CRYPTREC project. This paper shows that higher order differential attacks can be successful against 7-round versions of MISTY1 with FL functions. The attack on 7-round MISTY1 can recover a partial subkey with a data complexity of 254.1 and a computational complexity of 2120.8, which signifies the first successful attack on 7-round MISTY1 with no limitation such as a weak key. This paper also evaluates the complexity of this higher order differential attack on MISTY1 in which the key schedule is replaced by a pseudorandom function. It is shown that resistance to the higher order differential attack is not substantially improved even in 7-round MISTY1 in which the key schedule is replaced by a pseudorandom function.
Higher Order Differential Attack on 6-Round MISTY1 TSUNOO, Yukiyasu; SAITO, Teruo; NAKASHIMA, Hiroki ...
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences,
2009/01/01, 2009-00-00, 20090101, Letnik:
E92.A, Številka:
1
Journal Article
Recenzirano
MISTY1 is a 64-bit block cipher that has provable security against differential and linear cryptanalysis. MISTY1 is one of the algorithms selected in the European NESSIE project, and it has been ...recommended for Japanese e-Government ciphers by the CRYPTREC project. This paper reports a previously unknown higher order differential characteristic of 4-round MISTY1 with the FL functions. It also shows that a higher order differential attack that utilizes this newly discovered characteristic is successful against 6-round MISTY1 with the FL functions. This attack can recover a partial subkey with a data complexity of 253.7 and a computational complexity of 264.4, which is better than any previous cryptanalysis of MISTY1.
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