DAG-based BFT consensus has attracted growing interest in distributed data management systems for consistent replication in untrusted settings due to its high throughput and resilience to asynchrony. However, existing protocols still suffer from high communication overhead and long commit latency. In parallel, introducing minimal hardware trust has proven effective in reducing the complexity of BFT consensus. Inspired by these works, we present Fides, an asynchronous DAG-based BFT consensus protocol that, to our knowledge, is among the first to leverage TEEs to enhance both scalability and efficiency. Fides tolerates a minority of Byzantine replicas and achieves $O(κn^2 + n^3)$ metadata communication complexity through a customized TEE-assisted Reliable Broadcast (T-RBC) primitive with linear communication complexity in one-step broadcast.Building on T-RBC, Fides redefines the DAG construction rules by reducing the reference requirement from $2f+1$ to $f+1$ between consecutive vertices. This new structure weakens DAG connectivity and invalidates traditional commit rules, so we formally abstract the problem and derive new theoretical bounds of liveness. We further propose a four-round commit rule that achieves the theoretically minimal commit latency. Besides, we design two additional primitives, T-RoundCert and T-Coin, to efficiently certify DAG references and replace the costly cryptographic common coin used in prior protocols.Comprehensive evaluations on geo-distributed and local testbeds show that Fides substantially outperforms state-of-the-art protocols, including Tusk, Bullshark, Mysticeti, RCC, Damysus, Achilles and HybridSet, achieving lower latency and higher throughput while preserving strong safety and liveness guarantees.

翻译：基于有向无环图（DAG）的拜占庭容错（BFT）共识协议因其高吞吐量和对异步环境的强鲁棒性，在不可信环境下实现一致性复制的分布式数据管理系统中受到日益关注。然而，现有协议仍面临通信开销大和提交延迟高的问题。与此同时，引入最小化硬件信任机制已被证明能有效降低BFT共识的复杂度。受这些工作的启发，我们提出了Fides——一种基于DAG的异步BFT共识协议。据我们所知，该协议是首批利用可信执行环境（TEE）同时提升可扩展性与效率的协议之一。Fides可容忍少数拜占庭副本，并通过定制的具有线性通信复杂度的TEE辅助可靠广播原语（T-RBC），实现$O(κn^2 + n^3)$的元数据通信复杂度。基于T-RBC，Fides重构了DAG构建规则，将连续顶点间的引用需求从$2f+1$降低至$f+1$。这种新结构削弱了DAG连通性，并使传统提交规则失效。为此，我们对该问题进行了形式化抽象，并推导出新的活性理论边界。我们进一步提出一种四轮提交规则，实现了理论最小提交延迟。此外，我们设计了T-RoundCert与T-Coin两个附加原语，分别用于高效验证DAG引用和替代先前协议中代价高昂的密码学公共随机数生成机制。在广域分布式与本地测试平台上的综合评估表明，Fides在保持强安全性与活性保证的同时，显著优于包括Tusk、Bullshark、Mysticeti、RCC、Damysus、Achilles及HybridSet在内的前沿协议，实现了更低的延迟与更高的吞吐量。