Secure, fair and instant data trading scheme based on bitcoin

Abstract

Data trading scheme based on Bitcoins faces many challenges. One of them is the transactions’ fairness. That is, the distrust between the unfamiliar parties involved in the transaction is likely to cause unfair trade. For example, the party can provid inveracious data or refuse to pay after receiving the authentic data. Another one is the Bitcoin transaction latency, which causes the inability to reach an instant transaction. The third one is the illegal trading of data, for example, malicious agencies buy and sell users’ private data to make a profit. In order to address these challenges, we propose a secure, fair and instant data trading scheme. In this paper, we adopt a special Bitcoin script to reduce transaction latency. The script requires the payee to provide the payer the encryption key of data or he will not get Bitcoin. This effectively ensures fairness. If the same account is spent twice, the transaction’s script will expose the private key of the account. This allows Bitcoin transactions are completed instantly without waiting. In addition, by using identity-based signature and attribute-based encryption, we achieve the goal that only legitimate users can buy and sell data. What’s more, the data seller stores the data in the cloud, and the cloud server performs data auditing to ensure data integrity. Security analysis shows that our scheme is not only fair and reasonable, but also resistant to collusion attacks and double-spending attacks. Performance analysis shows that our scheme has a shorter execution time and is more suitable for real scenarios than other existing schemes.