The present disclosure relates to a 5G or pre-5G communication system for supporting a higher data transfer rate beyond a 4G communication system such as LTD. A method of a terminal connected to another base station (BS) for a second communication system in a wireless environment, the method comprising receiving, via the another BS from a BS for the first communication system, a radio resource control (RRC) connection reconfiguration message comprising information regarding a first key, generating a secure key for a security of the first communication system based on the first key, an identifier (ID) for indicating an algorithm for applying to the first key, a distinguisher for indicating a function of the algorithm indicated by the ID, and transmitting, to the BS, a signal based on the generated secure key.