BAC (Shell) is a public blockchain platform using a unique consensus algorithm DPOW. DPOW is translated into Chinese as Delegated Workload Proof. Miners are qualified to participate in mining by subscribing a certain amount of BAC. First, qualified miners enter the candidate pool and vote for decision makers in each round, and each miner has only one chance to vote in each round. The decision maker communicates with other nodes using the subscription-publishing mode of the MQTT protocol to complete the entire mining process. The miner who first calculates the correct result submits the content to the decision maker and verifies it, then completes the generation of a new block. Beike started research and development in early 2018, and proposed feasible solutions to the problems in transaction performance and security that are common in the current public chain.