The disclosure relates to a fifth generation (5G) or sixth generation (6G) communication system for supporting a higher data transmission rate. A method performed by a user equipment (UE) for performing network authentication is provided. The method includes determining, by the UE, a K-bit identification indicator indicating whether a length of an authentication key (K) stored in a subscriber identification module (SIM) is identified, selecting, by the UE, at least one security algorithm based on the K-bit identification indicator, and transmitting, by the UE to a network device, a registration request message including the K-bit identification indicator and information about the at least one security algorithm.