Data dynamic encryption communication method and system based on two-wire system communication

The invention discloses a data dynamic encryption communication method based on two-wire system communication. The method comprises main node equipment data encryption sending and slave node equipmentdata receiving and responding, and the main node equipment data encryption sending process comprises the steps that to-be-sent data is encrypted in a fixed encryption mode, then a random dynamic secret key is sent, secondary encryption is conducted on the data through the random dynamic secret key, reverse order sending is conducted, and reply is waited after sending is completed; data receivingand responding processes of the slave node equipment are as follows: when a dynamic random key signal exists on a bus, detecting and storing the dynamic random key signal, then receiving encrypted data, decrypting the encrypted data by utilizing a dynamic random key, then performing reverse processing, finally decrypting by adopting a fixed encryption mode to obtain original data, generating encrypted reply data, and sendi