Tight Private Circuits: Achieving Probing Security with the Least Refreshing
Tight Private Circuits: Achieving Probing Security with the Least Refreshing
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DOI：
10.1007/978-3-030-03329-3_12
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发表时间：
2018-12
期刊：
影响因子：
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通讯作者：
Sonia Belaïd;Dahmun Goudarzi;Matthieu Rivain
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文献类型：
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作者：
Sonia Belaïd;Dahmun Goudarzi;Matthieu Rivain
屏蔽是一种常见的对策，以保护实现免受侧信道攻击。2003年，Ishai，Sahai和瓦格纳提出了一种形式化的安全模型--命名探测模型，该模型目前被广泛应用于理论上对屏蔽实现的安全性进行推理。虽然许多作品已经提供了安全性证明的小掩蔽组件，calledgadgets，在这个模型中，没有正式的方法允许安全地组成小工具与一个紧密的股份数（即），直到最近。2016年，Bartheet等人用maskComp填补了这一空白，这是一种检查由几个小工具组成的掩码方案安全性的工具。这个工具可以通过在精心选择的位置插入掩码刷新小工具来实现可证明的安全性。然而，该方法并不严格，因为存在一些小工具的组成，对于这些小工具，它不能表现出缺陷，也不能证明安全性。因此，它过于保守，可能会插入比确保探测安全性实际需要更多的刷新小工具。在本文中，我们展示了第一个工具，称为astightPROVE，能够清楚地说明是否由标准小工具（加法，乘法和刷新）组成的共享电路是探测安全与否。给定这样的组合，我们的工具要么产生一个探测安全证明（在任何顺序有效）或展示一个安全缺陷，直接意味着在给定的顺序探测攻击。与maskComp相比，tightPROVE可以大大减少获得探测安全证明所需的刷新小工具的数量，从而减少一些安全共享电路的随机性要求。我们将我们的方法应用到最近的AES实现安全与高阶掩码位片，我们表明，我们可以保存所有的刷新小工具涉及的S盒层，这导致显着的性能增益。
Masking is a common countermeasure to secure implementations against side-channel attacks. In 2003, Ishai, Sahai, and Wagner introduced a formal security model, named-probing model, which is now widely used to theoretically reason on the security of masked implementations. While many works have provided security proofs for small masked components, calledgadgets, within this model, no formal method allowed to securely compose gadgets with a tight number of shares (namely,) until recently. In 2016, Bartheet al.filled this gap withmaskComp, a tool checking the security of masking schemes composed of several gadgets. This tool can achieve provable security with tight number of shares by inserting mask-refreshing gadgets at carefully selected locations. However the method is not tight in the sense that there exists some compositions of gadgets for which it cannot exhibit a flaw nor prove the security. As a result, it is overconservative and might insert more refresh gadgets than actually needed to ensure-probing security. In this paper, we exhibit the first tool, referred to astightPROVE, able to clearly state whether a shared circuit composed of standard gadgets (addition, multiplication, and refresh) is-probing secure or not. Given such a composition, our tool either produces a probing-security proof (valid at any order) or exhibits a security flaw that directly implies a probing attack at a given order. Compared tomaskComp,tightPROVEcan drastically reduce the number of required refresh gadgets to get a probing security proof, and thus the randomness requirement for some secure shared circuits. We apply our method to a recent AES implementation secured with higher-order masking in bitslice and we show that we can save all the refresh gadgets involved in the s-box layer, which results in an significant performance gain.