Attacking 44 Rounds of the SHACAL-2 Block Cipher Using Related-Key Rectangle Cryptanalysis

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概要

• 論文の詳細を見る

• SHACAL-2 is a 64-round block cipher with a 256-bit block size and a variable length key of up to 512 bits. It is a NESSIE selected block cipher algorithm. In this paper, we observe that, when checking whether a candidate quartet is useful in a (related-key) rectangle attack, we can check the two pairs from the quartet one after the other, instead of checking them simultaneously; if the first pair does not meet the expected conditions, we can discard the quartet immediately. We next exploit a 35-round related-key rectangle distinguisher with probability 2-460 for the first 35 rounds of SHACAL-2, which is built on an existing 24-round related-key differential and a new 10-round differential. Finally, taking advantage of the above observation, we use the distinguisher to mount a related-key rectangle attack on the first 44 rounds of SHACAL-2. The attack requires 2233 related-key chosen plaintexts, and has a time complexity of 2497.2 computations. This is better than any previously published cryptanalytic results on SHACAL-2 in terms of the numbers of attacked rounds.

• （社）電子情報通信学会の論文
• 2008-09-01

著者

• KIM Jongsung

  Center for Information Security Technologies (CIST), Korea University

• Kim Jongsung

  Center For Information Security Technologies (cist) Korea University

• LU Jiqiang

  Information Security Group, Royal Holloway, University of London

• Lu Jiqiang

  Information Security Group Royal Holloway University Of London

関連論文

• Seven New Block Cipher Structures with Provable Security against Differential Cryptanalysis
• Weak-Key Classes of 7-Round MISTY 1 and 2 for Related-Key Amplified Boomerang Attacks
• Attacking 44 Rounds of the SHACAL-2 Block Cipher Using Related-Key Rectangle Cryptanalysis

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