Redactable blockchain based on double-trapdoor chameleon hash family in private chain environment

The article proposes a redactable blockchain scheme based on the double-trapdoor chameleon hash family in a private chain environment to solve the key exposure problem that exists in the original chameleon hash as well as the high computational cost and storage cost caused by the need to compute the hash value multiple times when modifying the data on the chain. Compared with the original scheme, the scheme uses the double-trapdoor chameleon hash family that possess both one-time trapdoor and long-term trapdoor, making it impossible for an attacker to recover the long-term key through multiple known collisions and improving security. In terms of data modification, block administrators with trapdoor keys do not need to regenerate the hash value when modifying data, which reduces the computation and storage overhead and is friendly to users with limited resources. The system architecture based on the discrete logarithm problem has also been shown to be secure in previous literature. The final performance analysis surfaces that the proposed scheme has good efficiency and performance compared to the original scheme.