Advances in Cryptology - ASIACRYPT 2021 - 27th International Conference on the Theory and Application of Cryptology and Information Security, Singapore, December 6-10, 2021, Proceedings, Part I
Advances in Cryptology - ASIACRYPT 2021 - 27th International Conference on the Theory and Application of Cryptology and Information Security, Singapore, December 6-10, 2021, Proceedings, Part I
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密码学进展 - ASIACRYPT 2021 - 第 27 届密码学理论与应用与信息安全国际会议，新加坡，2021 年 12 月 6-10 日，会议记录，第一部分
DOI：
10.1007/978-3-030-92062-3_6
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
Basso A
中科院分区：
文献类型：
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作者：
Basso A
我们从Boneh，Kogan和Woo在Asiacrypt'20上提出的超奇异同构中对基于SIDH的不经意伪随机函数进行了密码分析。为此，我们给出了一个攻击的假设，辅助一个多的假设，这是由Boneh等人介绍的。我们表明，这导致了对不经意的PRF本身的攻击。该攻击打破了伪随机性，因为它允许对手在一些初始OPRF评估和一些离线计算之后评估OPRF，而无需与服务器进行进一步的交互。更具体地说，我们首先提出了一个多项式时间攻击。然后，我们认为很容易改变OPRF协议，包括一些对策，并提出了第二次亚指数攻击，成功地在存在上述对策。这两种攻击都打破了Boneh等人提出的安全参数。此外，我们提供了一个概念实现的证明以及我们的攻击的一些时间。最后，我们研究了OPRF参数之一的生成，并认为需要一个可信的第三方来保证可证明的安全性。
We cryptanalyse the SIDH-based oblivious pseudorandom function from supersingular isogenies proposed at Asiacrypt’20 by Boneh, Kogan and Woo. To this end, we give an attack on an assumption, the auxiliary one-more assumption, that was introduced by Boneh et al. and we show that this leads to an attack on the oblivious PRF itself. The attack breaks the pseudorandomness as it allows adversaries to evaluate the OPRF without further interactions with the server after some initial OPRF evaluations and some offline computations. More specifically, we first propose a polynomial-time attack. Then, we argue it is easy to change the OPRF protocol to include some countermeasures, and present a second subexponential attack that succeeds in the presence of said countermeasures. Both attacks break the security parameters suggested by Boneh et al. Furthermore, we provide a proof of concept implementation as well as some timings of our attack. Finally, we examine the generation of one of the OPRF parameters and argue that a trusted third party is needed to guarantee provable security.