Biclique Cryptanalysis of the Block Cipher SQUARE

Abstract. SQUARE, an 8-round substitution-permutation block cipher, is considered as the predecessor of the AES. In this paper, inspired from the recent biclique attack on the AES [5], we present the first single-key attack on full SQUARE. First, we introduce a biclique for 3 rounds of SQUARE using the independent related-key differentials. Then, we present an attack on the full round of this cipher with a data complexity of about 248 chosen plaintexts and a time complexity of about 2126 encryptions. Key words: Block cipher, cryptanalysis, biclique, differential, SQUARE.

• Type: Journal
• Year: 2011
• Where: IACR
• Authors: Hamid Mala
• Keywords: 3 Rounds, Cryptanalysis, IACR 2011, Time Complexity