该文利用高次DDO(Data Dependent Operations)结构的差分重量平衡性和SPN结构的高概率差分对构造了Eagle-128分组密码算法的两条5轮相关密钥-差分特征,通过连接两条5轮特征构造了完全轮相关密钥-矩形区分器,并对算法进行了相关密钥-矩形攻击,恢复出了Eagle-128算法的64 bit密钥。攻击所需的数据复杂度为281.5个相关密钥-选择明文,计算复杂度为2106.7次Eagle-128算法加密,存储复杂度为250 Byte存储空间,成功率约为0.954。分析结果表明,Eagle-128算法在相关密钥-矩形攻击条件下的有效密钥长度为192 bit。
By utilizing the balanceable difference weight of high order Data Dependent Operations (DDO) and the high probability differentials of SPN structures, two 5-round related-key differentials of Eagle-128 are constructed. A full round related-key rectangle distinguisher of Eagle-128 is constructed by connecting two 5-round related-key differentials, and a related-key rectangle attack is proposed on the cipher to recover 64 bit of the master key. The corresponding data complexity is about 281.5 related-key chosen-plain-text, the computation complexity is about 2106.7 encryptions of the cipher, and the storage complexity is about 250 Byte of storage space. The success rate of the attack is about 0.954. The analysis results show that the practical length of Eagle-128’s master key is 192 bit.