A user device configured to operate in a blockchain network includes a communicator; a memory; and a processor configured to: based on a peer-to-peer communication based content being received from at least one of a plurality of external apparatuses constituting the blockchain network, generate, through the communicator, block information related to the received content, store the generated block information in the memory, and transmit, through the communicator, the generated block information to the blockchain network; based on a user command for reporting the received content being received, transmit information on the reported content to the blockchain network; identify, based on verification on the reported content performed by at least one administrator device from among the plurality of external apparatuses, whether or not the reported content corresponds to an illegal content; and based on the reported content corresponding to the illegal content, block distribution of the received content.