可更改区块链技术研究

Research on Fault-correcting Blockchain Technology

近年来,区块链技术受到学术界和产业界的广泛关注和研究.区块链具有透明性、去信任、可追溯、不可更改等特点,吸引了不少企业开发基于区块链的应用.区块链不可更改是指区块链上的历史数据一旦确认就不能被更改,这一特点保证了区块链上历史数据的可靠性和完整性.然而区块链的不可更改并非绝对,在一些情况下,如区块链应用平台存在程序漏洞、某一历史记录存在错误但没被及时发现等,就有必要对出问题的历史记录做出响应和更改.针对区块链可更改方面的研究工作较少,埃森哲公司申请了可编辑区块链专利.其主要用到变色龙哈希函数这一工具,哈希函数的陷门由一个用户或多个用户共同掌管,从而将修改区块的权限交给一方或多方.因此,他们的方案需预先选定一个更改者,或由多个更改者进行交互完成更改.本文针对联盟链,设计了新的变色龙哈希函数,使得在满足修改触发条件的情况下,联盟链中的每个用户都有修改历史记录的权利.我们提出了多方共同决策的区块链更改方法,区块链的更改不依赖于一方,也不需要多方交互完成更改,只需要随机选出一个用户即可完成更改,因此整个过程的交互次数较少.

In recent years, blockchain technology has received extensive attention from academia and industry. Blockchain has the characteristics of transparency, de-trusting, traceability, and unchangeability, attracting many enterprises to develop blockchain-based applications. The unchangeability of blockchain means that the historical data on the blockchain cannot be changed once it is confirmed.This feature guarantees the reliability and integrity of the historical data on the blockchain. However,the unchangeablility of blockchain is not absolute. In some cases, such as a program loophole in the blockchain application platform, or a historic error not found in time,it is necessary to respond to and change the history of the problem. There is little research work on the blockchain changeability.Accenture applied for a patent about editable blockchain. It mainly uses the Chameleon Hash function.The trapdoor of the Hash function is managed by one node or multiple nodes, thus the edit authority is given to one or more parties. Therefore, the scheme needs to select a changer in advance, or interact with multiple changers to complete the change. This paper designs a new Chameleon Hash function for the alliance chain, so that each node in the alliance chain has the right to modify the history. We propose a blockchain error correction method for multi-party decision making. The blockchain modification does not depend on one party, and does not require multiple parties to complete the change. It only needs to randomly select a node to complete the change, so only a small number of interactions in the whole process is needed.