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Decentralized Data trading Model Based on a Public Blockchain

The big data industry has developed rapidly. It is of great significance for the healthy development of the big data industry to connect data supply-demand and promote data circulation through data trading. However, the existing third-party data trading platforms have the ability to view and steal transaction data and true identity. It has become a potential threat to both parties and an obstacle to data trading. Based on the research of blockchain technology, smart contract, and cryptography technology, this paper proposes a data trading model based on a blockchain for the security of data trading. The model uses the Interstellar File System (IPFS) and zero-knowledge proof to solve the security of data. Firstly, IPFS and cryptography are used to store and access data files safely. Secondly, based on secure storage and access, a data trading request is broadcast to a blockchain network. And the blockchain responds to the transaction request. Then, to obtain the original data file, the ciphertext got from the blockchain is decrypted based on the response message. Finally, the zero-knowledge proof system in the model is used to pay transaction fees to both parties. This process protects the security of payments. Through this model, both parties can complete the data trading. It also protects the security of data. In this paper, the proposed scheme is implemented on the Ethereum platform. The experimental results show that the proposed data trading model performs well in the security of data trading.