Block Auction: A General Blockchain Protocol for Privacy-Preserving and Verifiable Periodic Double Auctions

We use blockchain technology to tackle the problem of securing periodic double auctions for financial ‘dark pool’ trading, such that the privacy of pre-trade order information is preserved and the behaviour of the auction operator can be verified. A smart contract is used as a public audit trail without revealing the order intention of traders. Auction matching is performed off-chain, allowing alternative auction mechanisms to be used without altering the smart contract code. A full system implementation is deployed on the Harmony blockchain, and comparative evaluation of the protocol demonstrates some clear advantages over the closest published alternative.