Cross-chain bridge technologies in blockchain ecosystems are categorized into centralized and decentralized types. Centralized bridges， due to asset concentration， are vulnerable to attacks with potentially significant losses， while decentralized bridges align with the trustless principle but face challenges such as high resource demands， prolonged implementation cycles， and poor scalability issues. Limited research has addressed balancing single points of failure and operational efficiency in decentralized designs. To address these challenges， a semi-centralized cross-chain bridge architecture that integrates centralized and decentralized models was proposed. In this architecture， initial node services were provided by a central server， while decentralized services， including routing and staking， were facilitated by smart contracts on the blockchain. Firstly， participation of blockchain nodes was incentivized through a reward mechanism， and the trust was established via remote attestation using code signing and hash value verification. Secondly， the verified nodes were incorporated into a decentralized routing table to participate in cross-chain transaction verification and auditing. Finally， cross-chain transactions were validated using Hash Time Locked Contract （HTLC）. Experimental results on transaction costs and latency demonstrate that the proposed architecture reduces transaction latency to ［24，36］ seconds with a per-transaction cost of 403 299 gas， comparable to that of centralized cross-chain bridges； a security analysis identifies three typical cross-chain bridge attacks and corresponding solutions. The proposed semi-centralized cross-chain bridge architecture achieves performance comparable to that of centralized cross-chain bridges while maintaining the security of decentralized cross-chain bridges， balancing security， efficiency， and transaction costs in cross-chain operations.

Aiming at the performance bottleneck caused by multi-round inter-shard communication in cross-shard transaction protocols， an adaptive online blockchain sharding algorithm based on Trusted Execution Environments （TEE） was proposed. The algorithm optimizes the execution process of cross-shard transactions， reducing communication overhead and improving system throughput. Firstly， an adaptive online sharding algorithm was designed， which delayed the allocation time of transactions to shards， allowing related transactions to be clustered together， thereby reducing the number of cross-shard transactions and minimizing communication overhead. Secondly， by combining TEE technology， off-chain cross-shard transactions were securely and efficiently executed， eliminating the need for multi-round inter-shard communication in traditional schemes. Finally， a one-sided feedback optimization algorithm was introduced to dynamically adapt to changes in transaction patterns based on current system status and transaction demands， optimizing the sharding strategy in real time. Experimental results showed that compared with the random sharding algorithm， the proposed algorithm increased throughput by 35%. By reducing unnecessary communication and computational overhead， the proposed algorithm significantly improves overall system performance， while ensuring the security of cross-shard transactions. It is suitable for blockchain systems requiring high throughput and low latency， and has considerable application value.