A Redactable Blockchain Scheme Supporting Quantum-Resistance and Trapdoor Updates

Abstract

Applying chameleon hash functions to redactable blockchains is still challenging work. Most redactable blockchain solutions using this technique have potential problems, such as too weak decentralization performance and trapdoors with exposure risks. In addition, quantum computing also threatens the security of blockchain systems. The above two issues imply that the development of redactable blockchains is still constrained, and that quantum-resistance will be requirements for blockchain applications. Therefore, we constructed a chameleon hash function over lattices while utilizing a hierarchical identity mechanism to manage trapdoors and assign edit permissions. This variant of the chameleon hash function can support trapdoor updates and quantum-resistant performance, namely a hierarchical identity-based chameleon hash with revocable subkey (HIBCH-RS). We demonstrated the safety performance of HIBCH-RS by defining its safety concepts of collision resistance. Our HIBCH-RS scheme provides a solution for implementing a redactable blockchain with identity encryption and post-quantum cryptography. Finally, this quantum-resistant redactable blockchain was implemented on the Hyperledger Fabric blockchain platform.