Quantum attacks on Feistel constructions have attracted much more attention from worldwide cryptologists. To reduce the time complexity of quantum attacks on 7-round Feistel construction, we propose a quantum meet-in-the-middle attack based on quantum claw finding algorithm and 5-round distinguisher in Q1 model firstly. Compared with quantum attacks in Q2 model, our attack reduce the time complexity from $O({2^n})$ to $O({2^{7n/8}})$. Moreover, our attack belongs to Q1 model, which is more practical than Q2 model. When compared with best classical attacks, our attack not only reduces the time complexity, but also reduces the data and memory complexity by ${2^{n/2}}$ and ${2^{n/4}}$ respectively.
翻译:对费斯特尔建筑的量子攻击吸引了全世界密码学家的更多关注。 为了减少对7轮费斯特尔建筑的量子攻击的时间复杂性,我们建议首先以量子爪发现算法和Q1模型的5轮分辨器为基础,在中间进行量子攻击。与Q2模型的量子攻击相比,我们的攻击将时间复杂性从O({2 ⁇ }美元降低至O(2 ⁇ 7n/8 ⁇ )美元。此外,我们的攻击属于Q1模型,该模型比Q2模型更实用。与最好的古典攻击相比,我们的攻击不仅减少了时间复杂性,而且将数据和记忆复杂性分别降低了$2 ⁇ /2美元和$2 ⁇ /4美元。