Proxy Re-encryption based Fair Trade Protocol for Digital Goods Transactions via Smart Contracts

TL;DR

This paper presents a blockchain-based fair trade protocol for digital goods that uses proxy re-encryption and smart contracts to ensure security, fairness, and efficiency without relying on trusted third parties.

Contribution

It introduces an advanced passive proxy re-encryption scheme integrated with smart contracts to enable secure, fair, and decentralized digital goods transactions on blockchain.

Findings

Protocol supports ciphertext publicity and repeatable sales

Reduces interactions compared to existing solutions

Experiments confirm feasibility and effectiveness

Abstract

With the massive amount of digital data generated everyday, transactions of digital goods become a trend. One of the essential requirements for such transactions is fairness, which is defined as that both of the seller and the buyer get what they want, or neither. Current fair trade protocols generally involve a trusted third-party (TTP), which achieves fairness by heavily relying on the TTP's behaviors and the two parties' trust in the TTP. With the emergence of Blockchain, its decentralization and transparency make it a very good candidate to replace the TTP. In this work, we attempt to design a secure and fair protocol for digital goods transactions through smart contracts on Blockchain. To ensure security of the digital goods, we propose an advanced passive proxy re-encryption (PRE) scheme, which enables smart contracts to transfer the decryption right to a buyer after receiving his/her payment. Furthermore, based on smart contracts and the proposed passive PRE scheme, a fair trade protocol for digital goods transactions is proposed, whose fairness is guaranteed by the arbitration protocol. The proposed protocol supports Ciphertext publicity and repeatable sale, while involving less number of interactions. Comprehensive experiment results validate the feasibility and effectiveness of the proposed protocol.