Rijndael密码的逆序Square攻击

The Inverse Square Attack of Rijndael Cipher

2000年10月Rijnael被选为高级加密标准(AES),目前对它最有效攻击仍是由设计者提出的Square攻击。Square攻击是利用密码Square特性提出的选择明文攻击,可以对六轮和六轮以下的Rijndael密码进行成功的攻击,攻击六轮Rijndael的所有密钥的计算量为2×2^(72)+2^(64),五轮密码的复杂度为3×2^(40)+2^(32)。该文提出了逆序Square攻击算法,该算法是基于密码Square特性提出的选择密文攻击方法。它攻出六轮Rijndael密码的所有密钥的复杂度为2^(72)+2^(56),五轮密码的复杂度为2^(40)+2^(24)。若改变密钥扩散准则中的圈循环顺序,五轮密码的逆序Square攻击复杂度由2^(40)降为2^(32),六轮的攻击复杂度由2^(72)降为2^(64).

Rijndael was selected as the AES. The best-known attack against Rijndael is still the one presented by the designers called Square attack. Square attack is a chosen plaintext attack. In this paper a new kind of attack called Inverse Square attack is presented which is a kind of chosen cipher text attack and better than Square attack. It also shows that if only inverse the moving direction of RotByte transformation of key schedule, the complexity of the attack will be 28-factor bellow the complexity of Square attack.