Cryptanalysis of Skipjack Reduced to 31 Rounds Using Impossible Differentials

AbstractIn this paper we present a cryptanalytic technique, based on impossible differentials. We use it to show that recovering keys of Skipjack reduced from 32 to 31 rounds can be performed faster than exhaustive search. We also describe the Yoyo game (a tool that can be used against reduced-round Skipjack), and other properties of Skipjack.

[1]  Martin E. Hellman,et al.  A cryptanalytic time-memory trade-off , 1980, IEEE Trans. Inf. Theory.

[2]  Eli Biham,et al.  Miss in the Middle Attacks on IDEA and Khufu , 1999, FSE.

[3]  Eli Biham,et al.  Cryptanalysis of Skipjack reduced to 31 rounds using impossible differentials , 1999 .

[4]  A. Shimizu,et al.  Fast data encipherment algorithm FEAL-8 , 1978 .

[5]  Xuejia Lai,et al.  Markov Ciphers and Differential Cryptanalysis , 1991, EUROCRYPT.

[6]  Louis Granboulan.  Flaws in differential cryptanalysis of Skipjack , 2001, IACR Cryptol. ePrint Arch..

[7]  Eli Biham,et al.  Miss in the Middle Attacks on IDEA, Khufu and Khafre , 1999, FSE 1999.

[8]  Louis Kruh,et al.  Machine Cryptography and Modern Cryptanalysis , 1985 .

[9]  Vincent Rijmen,et al.  Two Attacks on Reduced IDEA , 1997, EUROCRYPT.

[10]  Eli Biham,et al.  Differential cryptanalysis of Lucifer , 1993, Journal of Cryptology.

[11]  Sangjin Lee,et al.  Saturation Attacks on Reduced Round Skipjack , 2002, FSE.

[12]  Mitsuru Matsui,et al.  Linear Cryptanalysis Method for DES Cipher , 1994, EUROCRYPT.

[13]  Shoji Miyaguchi,et al.  Fast Data Encipherment Algorithm FEAL , 1987, EUROCRYPT.

[14]  David A. Wagner,et al.  Truncated Differentials and Skipjack , 1999, CRYPTO.

[15]  Eli Biham,et al.  Cryptanalysis of Ladder-DES , 1997, FSE.

[16]  Eli Biham,et al.  Differential Cryptanalysis of the Data Encryption Standard , 1993, Springer New York.

[17]  Ralph Howard,et al.  Data encryption standard , 1987 .

[18]  Eli Biham,et al.  Initial Observations on Skipjack: Cryptanalysis of Skipjack-3XOR , 1998, Selected Areas in Cryptography.

[19]  Ralph C. Merkle,et al.  Fast Software Encryption Functions , 1990, CRYPTO.

[20]  Jeff Gilchrist,et al.  The CAST-256 Encryption Algorithm , 1999, RFC.

[21]  David A. Wagner,et al.  Markov Truncated Differential Cryptanalysis of Skipjack , 2002, Selected Areas in Cryptography.