In this paper, a secure and trust-based group key management protocol (GKMP) is presented for non-networks such as MANET/VANET. The scheme provides secure communication for group members in a dynamic network environment and does not restrict the users (registered or non-registered), allowing for flexible group communication. The proposed scheme is designed to address the challenges of key distribution, secure grouping, and secure communication. For result evaluation, first of all formal and informal security analysis was done and then compared with existing protocols. The proposed trust-based GKMP protocol satisfies the authentication, confidentiality of messages, forward/backward security concurrently as well as shows robustness in terms of packet delivery ratio and throughput
