A new lightweight additive homomorphic encryption algorithm

This article describes a lightweight additive homomorphic algorithm with the same encryption and decryption keys. Compared to standard additive homomorphic algorithms like Paillier, this algorithm reduces the computational cost of encryption and decryption from modular exponentiation to modular multiplication, and reduces the computational cost of ciphertext addition from modular multiplication to modular addition. This algorithm is based on a new mathematical problem: in two division operations, whether it is possible to infer the remainder or divisor based on the dividend when two remainders are related. Currently, it is not obvious how to break this problem, but further exploration is needed to determine if it is sufficiently difficult. In addition to this mathematical problem, we have also designed two interesting mathematical structures for decryption, which are used in the two algorithms mentioned in the main text. It is possible that the decryption structure of Algorithm 2 introduces new security vulnerabilities, but we have not investigated this issue thoroughly.