Transaction privacy protection method based on block chain

The invention belongs to the technical field of block chains, and particularly relates to a transaction privacy protection method based on a block chain. The method comprises the following steps: step 1, defining a block chain comprising a plurality of blocks; 2, creating a population for representing the block chain; 3, calculating the fitness of each individual; 4, updating the priority and the position of each individual to find an optimal privacy factor; 5, updating the optimal position of each individual and the global optimal position; 6, randomly selecting some transactions in the block chain, and putting the transactions into a transaction pool; recalculating the fitness of each individual; 7, updating the priorities and the positions of the individuals again; 8, updating the optimal position and the global optimal position of each individual again; and 9, taking the found global optimal position as a final privacy factor, and applying the final privacy factor to a transaction to be executed. Accordin