An NTRU Lattice-Based Chameleon Hash Scheme for Redactable Blockchain Applications

With the development of quantum technology, difficult problems related to traditional cryptographic schemes based on number theory have been impacted. The NTRU lattice has been increasingly used in recent cryptography schemes because of its high efficiency, compactness and quantum resistance. This paper constructs a chameleon hash function based on the NTRU lattice. The scheme consists of three parts: a key generation algorithm, a hash value calculation algorithm, and an effective collision finding algorithm. The basic arithmetic operation in the scheme is performed in a polynomial ring, which can be accelerated using modern implementation technology, and a security analysis is performed, which proves its collision resistance and semantic security. This means that the scheme can combine the advantages of simplicity and security of the NTRU lattice to efficiently realize the functions of the chameleon hash scheme. The scheme is also extended in the key generation stage and collision construction stage. Based on the {0,1}-linear secret sharing scheme, the proposed chameleon hash scheme is supplemented with a distributed trapdoor sharing function and applied to a redactable blockchain, which prevents the abuse of modification permissions to a certain extent. At the same time, this paper also conducts a comparative analysis of other lattice-based chameleon hash functions, demonstrating the scheme’s pertinence and practicality.