The rapid expansion of distributed energy resources (DERs) has driven the emergence of virtual power plants (VPPs) as decentralized energy trading platforms that enhance grid flexibility and market efficiency. However, the increasing reliance on digital infrastructure has exposed VPP transactions to cyber-threats such as double-spending attack, Sybil attack, smart contract tampering, and malicious data injection attack, undermining transaction integrity and market stability. Traditional cybersecurity mechanisms, which often rely on centralized verification, are vulnerable to single points of failure and lack adaptive defense strategies. To address these challenges, this paper proposes a blockchain-enabled cyber-resilient trading framework that integrates game-theoretic smart contract optimization, Byzantine fault tolerance (BFT) consensus mechanisms, and zero-knowledge proof (ZKP) authentication to enhance cybersecurity, efficiency, and privacy in VPP transactions. The proposed framework leverages a multi-layered cybersecurity approach where game-theoretic modeling ensures optimal cybersecurity investment by balancing transaction efficiency and cybersecurity costs. A Stackelberg game modeling models the interactions among prosumers, VPP aggregators, and cyber attackers, allowing the system to allocate cybersecurity resources strategically. ZKP authentication ensures that transactions are validated without exposing sensitive trading information, mitigating privacy risks while maintaining transparency. To enhance resilience, a reinforcement learning-based adaptive defense mechanism continuously optimizes cybersecurity policies against evolving cyber-threats, improving attack detection and mitigation efficiency. The proposed framework incorporates multi-signature validation and BFT consensus mechanisms to prevent unauthorized modifications, while smart contracts autonomously execute transactions under predefined cybersecurity policies.