Apparatus and method for achieving distributed consensus based on decentralized byzantine fault tolerance

An apparatus for achieving distributed consensus based on decentralized Byzantine fault tolerance, comprising:

• one or more processors;
• and
• an execution memory for storing at least one program that is executed by the one or more processors,
• wherein the at least one program is configured to:
• receive delegate request messages, each including a first transaction for requesting distributed consensus proposed by a client, from congress candidate nodes in a blockchain, and determine congress candidate nodes forming a consensus quorum, among the congress candidate nodes, to be consensus nodes based on the delegate request messages,
• generate a prepare message that includes a second transaction for obtaining consent to results of determination of the consensus nodes from the consensus nodes, and send the prepare message to the consensus nodes, and
• receive commit messages, each including an electronic signature of a corresponding consensus node, in response to the prepare message from the respective consensus nodes, and broadcast a reply message indicative of results of verification of the electronic signatures included in the commit messages, to the congress candidate nodes, thus completing distributed consensus,
• wherein the consensus quorum is 2f+1, where f is an integer of 1 or more,
• wherein f satisfies both a first condition and a second condition,
• wherein the first condition is a condition satisfied in a case where, when the congress candidate nodes are selected from among all nodes of the blockchain with a probability of p (where p is a real number that is equal to or greater than 0 and is less than or equal to 1), a first probability that a number of Byzantine nodes to be selected as the congress candidate nodes will be greater than f is less than or equal to a preset first reference probability, and
• wherein the second condition is a condition satisfied in a case where a second probability that a number of congress candidate nodes will be less than or equal to 3f is less than or equal to a preset second reference probability.