An image forming device and an operating method of an image forming device are provided. The operating method includes receiving first authentication information corresponding to an account of a first user, when the account of the first user is authenticated according to the first authentication information, preparing an operation of the image forming device according to usage authorization of the first user; receiving a request to provide job information of the first user, obtaining a first job list of the first user from a ledger on which job information of a user with respect to a certain image forming job is recorded, based on a blockchain in which the ledger is distributed and managed, and performing a first image forming job selected from the first job list.