A blockchain-based signature exchange protocol for metaverse

Electronic Commodity Trading has a pivotal role in our economic activities. In the literature, there is a classic problem called “Fair Exchange” which is fundamental to electronic commodity trading. It means the participants can receive the exchange item of the counterparty as they have agreed on before. Since the ownership of items online is often authorized by digital signatures, we focus on the problem of the fair exchange of digital signatures in this paper. As the concept of the Metaverse becomes popular recently, what we are concerned about is how the fair exchange will evolve in a metaverse. It is said that the metaverse is a vision of how the next generation of the internet will operate and the research for the fair exchange problem in it is essential for a wide range of applications like trading a (Non-fungible-token) NFT. Many cryptographic fair exchange protocols are proposed to deal with such a problem. However, most of them should rely on a Trusted Third Party (TTP) and the security is restricted by the TTP. The way the metaverse will work is still being defined. But it will probably provide users with a decentralized environment and a fair exchange protocol relying on a TTP seems unsuitable for it. Recently, researchers present some blockchain-based fair exchange protocols to get rid of or reduce the power of a TTP. But these blockchain-based protocols face new challenges. Firstly, cryptography pairing operations are often contained in such a TTP-free protocol and cost too much for the blockchain. Secondly, the player may hang for an unacceptably long time of the latency of the blockchain network. Thirdly, it is difficult to protect the privacy of the signatures while making the whole protocol verifiable at the same time. To bridge these research gaps, this paper presents a novel signature exchange protocol called DFSE which is decentralized, verifiable, efficient and autonomous. To give a real-world evaluation, we perform the experiment on the live test network of Ethereum and the results show that our protocol is feasible.