Efficient chameleon hash functions in the enhanced collision resistant model
Efficient chameleon hash functions in the enhanced collision resistant model
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DOI：
10.1016/j.ins.2019.09.001
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发表时间：
2020-02
期刊：
影响因子：
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通讯作者：
Mojtaba Khalili;Mohammad Dakhilalian;W. Susilo
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文献类型：
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作者：
Mojtaba Khalili;Mohammad Dakhilalian;W. Susilo
当仅知道函数的散列键时，变色龙散列函数是抗冲突的。特别是，在不知道秘密信息的情况下，变色龙哈希函数只是像常规的密码哈希函数一样，很难发现冲突。然而，任何拥有活门钥匙的人都可以高效地为变色龙散列函数生成预映像。在一些应用中，例如可编辑的区块链，不幸的是，现有的属性不够，我们需要更多的功能。实际上，它要求在不知道陷门密钥的情况下，没有人可以计算冲突，即使他可以看到任意哈希函数的冲突。2017年，Ateniese等人提出。在增强的抗碰撞模型中引入了变色龙散列函数的概念，并在标准模型中提出了一种满足这些特征的构造方法。到目前为止，这种变色龙散列函数的有效构造仍然是一个开放的研究问题。在这篇文章中，我们肯定地回答了这个问题，给出了满足增强的抗碰撞能力的变色龙散列函数的有效构造。这项工作的贡献是双重的。首先，我们指出了前人工作的不足。然后，我们继续以更高的效率提出新的方案。从技术上讲，我们在基本模型中提出了一种新的变色龙散列函数，并基于简单的假设。该变色龙散列函数与Groth-Sahai证明体制和Cramer-Shoup加密方案具有很好的兼容性，可以作为增强抗碰撞模型中构造高效变色龙散列函数的垫脚石。此外，我们证明了我们的基本变色龙散列可以与Groth和Maller的最优ZK-snarks相结合，从而在增强的抗碰撞模型中导致变色龙散列函数的长度更短。
Chameleon hash functions are collision resistant when only the hashing keys of the functions are known. In particular, without the knowledge of the secret information, the chameleon hash function is merely like a regular cryptographic hash function, where it is hard to find collisions. However anyone who has trapdoor keys can efficiently generate pre-images for the chameleon hash function. In some applications, such as redactable blockchains, unfortunately the existing properties do not suffice and we need more features. Actually, it is required that without knowing the trapdoor keys, nobody can compute collisions, even if he can see collisions for arbitrary hash functions. In 2017, Ateniese et al. introduced the notion of chameleon hash functions in the enhanced collision resistant model and proposed a construction in the standard model satifying the features. To date, efficient constructions of this kind of chameleon hash functions remain as an open research problem. In this paper, we answer this problem affirmatively by presenting efficient constructions of the chameleon hash function satisfying the enhanced collision resistance. The contributions of this work are twofold. First, we show the weakness of previous work. Then, we proceed with proposing new schemes with more efficiency. Technically, we present a new chameleon hash function in the basic model and based on simple assumptions. This chameleon hash function is well compatible with Groth-Sahai proof systems and the Cramer-Shoup encryption schemes, and can be used as a stepping stone to construct an efficient chameleon hash function in the enhanced collision resistant model. Moreover, we show our basic chameleon hash can be combined with optimal ZK-SNARKs of Groth and Maller that leads to shorter sizes for chameleon hash function in the enhanced collision resistant model.