3) The stage of intra-day double auction transaction• The function of Bid/Ask: Within the response day, users with authority can adopt the function to submit the purchase/sell quotation and volume information of DR quota to the blockchain before the end of the double auction period. The function will judge the timeliness of all the bidding information and add the bidding information of different users to the buyer's or seller's queue respectively.• The function of sorting: The GC takes the function to sort the quotation queue. The queue of buyers isarranged in descending order of quotation and the queue of sellers is arranged in ascending order of quotation. Note that the same quotation will be arranged in chronological order. • The function of matching and settlement: The function will match the queue of buyer and seller according to the double auction rules, and carry out the transfer and settlement of DR quotas for the users who made a deal. The matching algorithm of double auction is described in detail as shown in Fig. 4.