CHSTS: Chameleon Hash based on Schnorr threshold signature on Editable Blockchain

Blockchain's immutability, while a core feature, can pose challenges in cases involving sensitive information or compliance with legal regulations, hindering its development. Many subsequent works designed editable blockchains based on the chameleon hash function proposed by H. Krawczyk et al. to solve the above problems. However, existing editable blockchain solutions lack security and are inefficient. To address the security and efficiency issues, we introduce the novel concept of Chameleon hashing based on Schnorr threshold signatures (CHSTS). The CHSTS scheme has double trapdoors, the publisher of the message owns the long-term trapdoor, and the editorial committee owns the ephemeral trapdoor. Message publishers can collaborate with the editorial committee to modify their published information, preventing the exposure of private data, facilitating oversight during the editing process, and enabling the tracking of malicious users. We have designed an updatable ephemeral trapdoor based on Schnorr signatures, effectively avoiding the inefficiencies associated with bilinear pairing. Experimental results show that our CHSTS scheme has a significant advantage in computational cost.

I. Introduction

Blockchain is a decentralized technology [1] that has gar-nered significant attention following the success of Bitcoin. Recently, researchers have explored and developed various applications based on blockchain systems, including mobile edge computing [2], and electronic voting [3]. These applications leverage the inherent property of blockchain known as immutability, which means that the transaction information (e.g., sensor data and transaction bills) stored in a block cannot be tampered once it is recorded.