Instant messaging method and device based on blockchain, and medium

The invention discloses an instant messaging method and device based on a blockchain, and a medium. The method comprises the following steps: receiving a communication invitation sent by a first user for requesting communication from a second user by the first user; determining a communication authority between the first user and the second user through authority information stored in the blockchain, and determining whether to send the communication invitation to the second user according to the communication authority; if the communication invitation is sent to the second user, determining a communication mode between the first user and the second user according to feedback of the second user. According to the embodiment of the invention, the blockchain technology and various encryption algorithms are utilized, the security and reliability of the communication process are ensured through invitation and reply mechanisms before communication, and the possible conditions of information mistaken sending and hara