Blockchain technologies have attracted a large amount of attention recently, with immutability as a basic property. However, it is often desired to allow editing a transaction or a block in a controlled way. Chameleon hash function, with enhanced collision-resistance property, has recently found to be an important tool to construct redactable blockchain. This means that the traditional key-exposure free (double-trapdoor) constructions are unsuitable for the applications here. Although single-trapdoor key-exposure free chameleon hash functions naturally satisfy enhanced collision-resistance, they are very rare, and none is based on quantum-resistant assumptions.

In this paper, we propose two single-trapdoor key-exposure free chameleon hash functions based on lattice, without/with lattice trapdoors respectively, and show their applications in redactable blockchain. Our constructions do not need heavy cryptographic tools, such as encryption and NIZK, therefore are more compact and computational efficient than schemes following Ateniese et al.’s generic transformation framework of PKE+NIZK. Moreover, we introduce two mechanisms in order to prevent the misuse of redaction functionality in blockchain. We present a fully distributed key management mechanism for the first scheme, and solve the redaction-misuse problem which remains in blockchains using Ateniese et al.’s generic framework. We also suggest the voting strategy when applying our second scheme. Finally, we show how to efficiently integrate our chameleon hash with any blockchain technologies, with only minor changes to the current blockchains in use. For extend interests, our proposed chameleon hash functions are also suitable for constructing quantum-resistant chameleon signatures and off-line/on-line signatures.

区块链技术以不变性为基本属性，最近引起了广泛的关注。但是，通常希望允许以受控方式编辑事务或块。变色龙哈希函数具有增强的抗碰撞性，最近被发现是构建可编辑区块链的重要工具。这意味着传统的无按键曝光（双活板门）结构不适用于此处的应用。尽管单活板门无键暴露的变色龙哈希函数自然可以满足增强的抗碰撞性，但它们非常罕见，并且都不基于抗量子假设。

在本文中，我们提出了两个分别基于无格和无格陷阱门的基于单格无钥匙暴露的变色龙哈希函数，并展示了它们在可编辑区块链中的应用。我们的构造不需要繁重的加密工具，例如加密和NIZK，因此比遵循Ateniese等人的PKE + NIZK通用转换框架的方案更紧凑，计算效率更高。此外，我们引入了两种机制，以防止在区块链中滥用编校功能。我们为第一种方案提供了一种完全分布式的密钥管理机制，并使用Ateniese等人的通用框架解决了存在于区块链中的密文滥用问题。在采用第二种方案时，我们也建议采用投票策略。最后，我们展示了如何有效地将我们的变色龙哈希与任何区块链技术集成在一起，并且仅对当前使用的区块链进行微小的更改。为了扩展兴趣，我们提出的变色龙哈希函数也适用于构造抗量子变色龙签名和离线/在线签名。