Coefficient Grouping: Breaking Chaghri and More
Coefficient Grouping: Breaking Chaghri and More
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DOI：
10.1007/978-3-031-30634-1_10
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发表时间：
2022
期刊：
影响因子：
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通讯作者：
Fukang Liu;Ravi Anand;Libo Wang;W. Meier;Takanori Isobe
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文献类型：
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作者：
Fukang Liu;Ravi Anand;Libo Wang;W. Meier;Takanori Isobe
我们提出了一种称为系数分组的有效技术来评估FHE友好密码CHAGRI的代数度，该技术已被ACM CCS 2022接受。结果表明，代数阶数的增加是线性的，而不是指数的。因此，我们可以构造一个具有时间和数据复杂性的13轮识别器，并发动13.5轮的密钥恢复攻击。具体地说，在时间和数据复杂度为的情况下，可以实现对8轮Chaghri的高阶差分攻击。因此，这表明整整8轮距离安全还很远。此外，我们还展示了我们的系数分组技术在安全密码组件设计中的应用。结果，我们找到了解决查格里问题的对策，与最初的设计相比，它几乎没有什么开销。由于定义在大型有限域上的对称基元越来越多，我们相信我们的新技术将在未来的研究中有更多的应用。
We propose an efficient technique called coefficient grouping to evaluate the algebraic degree of the FHE-friendly cipher Chaghri, which has been accepted for ACM CCS 2022. It is found that the algebraic degree increases linearly rather than exponentially. As a consequence, we can construct a 13-round distinguisher with time and data complexity ofand mount a 13.5-round key-recovery attack. In particular, a higher-order differential attack on 8 rounds of Chaghri can be achieved with time and data complexity of. Hence, it indicates that the full 8 rounds are far from being secure. Furthermore, we also demonstrate the application of our coefficient grouping technique to the design of secure cryptographic components. As a result, a countermeasure is found for Chaghri and it has little overhead compared with the original design. Since more and more symmetric primitives defined over a large finite field are emerging, we believe our new technique can have more applications in the future research.