The present disclosure relates to a communication method and system for converging a 5th-Generation (5G) communication system for supporting higher data rates beyond a 4th-Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. Methods and systems for generating/deriving CU-UP security keys for disaggregated gNB architecture are described herein. A UE/gNB can inform the gNB/UE about the capability of the UE/gNB to derive CU-UP security keys. CU-UP security keys comprise an integrity protection key and a ciphering key. The gNB derives an integrity protection key and a ciphering key upon determining that the UE supports derivation of the CU-UP security keys or the UE has capability to derive CU-UP security keys. The integrity protection key protects the integrity of data, in a DRB, traversing through a CU-UP. The ciphering key encrypts the data, in the DRB, traversing through the CU-UP. The gNB sends RRC connection reconfiguration messages, which include multiple parameters. The UE derives an integrity protection key and a ciphering key, for each DRB, based on the plurality of parameters, for protecting the integrity of the data and encrypting the data.