Bpf-payment: Fair payment for cloud computing with privacy based on blockchain and homomorphic encryption

Cloud computing is popular because it can provide low-cost, high-performance data processing services. However, since cloud computing transactions between users and service providers are usually asynchronous, data privacy and online payment issues involving users and service providers often lead to a crisis of trust, which may hinder the development of cloud computing and application. Most existing solutions only consider a certain type of service or solving one of them. In this paper, we propose BPF-Payment, a fair payment scheme for cloud computing with privacy based on blockchain and homomorphic encryption, which achieves correctness, fairness, compatibility, and a lightweight client. BPF-Payment solves the problem of unfair payment in cloud computing by introducing blockchain as a third party. It also uses the Paillier homomorphic encryption scheme to enable blockchain to perform verification of problem solutions without accessing problem-related data, thereby ensuring data privacy. To verify the security and practicability of BPF-Payment, we instantiate BPF-Payment based on the Paillier homomorphic encryption scheme and evaluate the implementation. We test the performance of key generation, encryption and decryption, and verification in the BPF-Payment scheme on the FISCO-BOCS blockchain. The experimental results show that the time and gas consumption of BPF-Payment are reasonable and acceptable.