约减轮数分组密码LEA的差分分析

Differential Analysis of Reduced Rounds Block Cipher LEA

LEA算法是面向软件的轻量级加密算法,在2019年成为ISO/IEC国际标准轻量级加密算法,具有快速加密、占用运算资源少等优点。该文基于多条输入输出差分相同的路径计算了差分概率,首次对LEA-128进行了13轮和14轮的密钥恢复攻击;采用提前抛弃技术,分别在12轮和13轮差分特征后面添加了1轮,恢复了96 bit密钥;其中13轮的密钥恢复攻击数据复杂度为2^(98)个明文,时间复杂度为2^(86.7)次13轮LEA-128解密;14轮的密钥恢复攻击数据复杂度为2118个明文,时间复杂度为2^(110.6)次14轮LEA-128解密。

The LEA algorithm is a software-oriented lightweight encryption algorithm,which became the ISO/IEC international standard lightweight encryption algorithm in 2019.It has the advantages of fast encryption and less computing resources.The differential probability is calculated based on multiple paths with the same input-output difference,13 and 14 rounds of key recovery attacks of LEA-128 are given for the first time.Using the early abort technology,one round is added after the 12-round and 13-round differential characteristic,and a total of 96 bit keys are recovered.The 13-round key recovery attack has a data complexity of 2^(98) plaintext and a time complexity of 286.7 times of 13 rounds of LEA-128 decryption;the 14-round key recovery attack has a data complexity of 2^(118) plaintext and a time complexity of 2^(110.6) times of 14 rounds of LEA-128 decryption.