Cross-chain interoperability remains one of the most critical challenges in blockchain technology, particularly within decentralized finance (DeFi) ecosystems. Current bridge protocols suffer from security vulnerabilities, high transaction costs, and limited scalability. This paper proposes a novel Consensus-Based Bridge Protocol (CBBP) that leverages multi-signature validation combined with zero-knowledge proofs to enable secure, efficient, and scalable cross-chain asset transfers. Our experimental results demonstrate a 43% reduction in transaction costs and a 67% improvement in security metrics compared to existing bridge solutions. The protocol has been tested across Ethereum, Polygon, and Binance Smart Chain networks, showing promising results for real-world implementation.