关键词: 可修正区块链, 变色龙哈希, 联盟链, 多用户, 分叉引理, 离散对数问题

Abstract: Due to the lack of supervision strategies,the inclusion of suspicious or harmful information,and the inability to modify data after being uploaded to the chain,the existing blockchain architecture is likely to become an extrajudicial place for low-cost cybercrime,thus limiting its usability.The redactable blockchain scheme is considered to be an effective way to solve this pro-blem,but how to combine this concept with the advantages of the consortium blockchain is an unresolved technical problem.To this end,in this paper,a new cryptographic scheme is put forward,which extends the concept of chameleon hash functions to multi-user scenarios by introducing the group key,and improves the solution to the problem of centralized modification rights caused by a single user holding the whole trapdoor key.On this basis,a consortium-oriented redactable blockchain scheme is proposed,which adopts a two-stage model of request-verification to complete the modification.Under the general model and random oracle model,based on the discrete logarithm assumption,it is proved that the scheme is collision-free and multi-user secure.Simulation experiments and comparative analysis also demonstrate the effectiveness and usability of the scheme.

Key words: Redactable blockchain, Chameleon hash, Consortium blockchain, Multi-user, Forking lemma, Discrete logarithm problem