二次检测立方攻击改进与实现

对二次检测立方攻击预处理阶段的提取二次表达式的算法进行了改进以优化攻击效率。将秘密变量的变化引入攻击中，使得攻击模型更加灵活；同时，利用时空折中的思想，通过存储常数项和一次项的计算结果，有效降低二次项的计算量。将改进的方法应用于简化版的PRESENT算法和Trivium算法上，攻击效率有显著提高。
The algorithm of extracting quadratic expressions in the pre-processing phase of cube attack with quadratic test was enhanced to optimize the attack efficiency. The variation of secret keys was introduced into cube attack, which makes the model much more flexible. At the same time, with the help of the trade-off between time and space, the complexity of extracting quadratic terms was reduced by storing the results of the constant and linear terms. The improved method was applied to the simplified PRESENT and Trivium algorithms and it turns out that the attack efficiency is enhanced obviously.