Byzantine Fault Tolerant (BFT) consensus protocols for dynamically available systems face a critical challenge: balancing latency and security in fluctuating node participation. Existing solutions often require multiple rounds of voting per decision, leading to high latency or limited resilience to adversarial behavior. This paper presents a BFT protocol integrating a pre-commit mechanism with publicly verifiable secret sharing (PVSS) into message transmission. By binding users' identities to their messages through PVSS, our approach reduces communication rounds. Compared to other state-of-the-art methods, our protocol typically requires only four network delays (4$Δ$) in common scenarios while being resilient to up to 1/2 adversarial participants. This integration enhances the efficiency and security of the protocol without compromising integrity. Theoretical analysis demonstrates the robustness of the protocol against Byzantine attacks. Experimental evaluations show that, compared to traditional BFT protocols, our protocol significantly prevents fork occurrences and improves chain stability. Furthermore, compared to longest-chain protocol, our protocol maintains stability and lower latency in scenarios with moderate participation fluctuations.