A method for communicating between devices is presented. The method includes dividing a first public key of a first device into at least two partial keys, transmitting the at least two partial keys through at least two communication channels having different physical characteristics, receiving a second public key of a second device through at least one of the at least two communication channels, authenticating the second device based on the received second public key, and performing secure communication with the second device using a public key generated based on the received second public key.