Cognitive radio networks have received more research interest in recent years as they can provide a favourable solution to spectrum scarcity problem prevailing in the wireless systems. This paper presents a new key agreement protocol called ‘TKTOFT’ with modified batch rekeying algorithm for distributed group oriented applications in cognitive radio networks by integrating a ternary key tree and an one way function. It is inferred from the experimental results that TKTOFT outperforms the existing one way function based protocol both in terms of computation and communication overhead. Hence, TKTOFT is suited for establishing secure and quick group communication in dynamic groups in cognitive radio networks.