The Byzantine Agreement (BA) problem is a fundamental challenge in distributed systems, focusing on achieving reaching an agreement among parties, some of which may behave maliciously. With the rise of cryptocurrencies, there has been significant interest in developing atomic broadcast protocols, which facilitate agreement on a subset of parties' requests. However, these protocols often come with high communication complexity ($O(ln^2 + \lambda n^3 \log n)$, where $l$ is the bit length of the input, $n$ is the number of parties, and $\lambda$ represents the security parameter bit length). This can lead to inefficiency, especially when the requests across parties exhibit little variation, resulting in unnecessary resource consumption. In this paper, we introduce Slim-ABC, a novel atomic broadcast protocol that eliminates the $O(ln^2 + \lambda n^3 \log n)$ term associated with traditional atomic broadcast protocols. While Slim-ABC reduces the number of accepted requests, it significantly mitigates resource wastage, making it more efficient. The protocol leverages the asynchronous common subset and provable-broadcast mechanisms to achieve a communication complexity of $O(ln^2 + \lambda n^2)$. Despite the trade-off in accepted requests, Slim-ABC maintains robust security by allowing only a fraction ($f+1$) of parties to broadcast requests. We present an extensive efficiency analysis of Slim-ABC, evaluating its performance across key metrics such as message complexity, communication complexity, and time complexity. Additionally, we provide a rigorous security analysis, demonstrating that Slim-ABC satisfies the \textit{agreement}, \textit{validity}, and \textit{totality} properties of the asynchronous common subset protocol.

翻译：拜占庭协议（BA）问题是分布式系统中的一个基础性挑战，其核心在于如何在部分参与方可能恶意行为的情况下达成共识。随着加密货币的兴起，开发原子广播协议引起了广泛关注，这类协议有助于就参与方请求的一个子集达成一致。然而，这些协议通常具有较高的通信复杂度（$O(ln^2 + \lambda n^3 \log n)$，其中 $l$ 为输入的比特长度，$n$ 为参与方数量，$\lambda$ 表示安全参数的比特长度）。这可能导致效率低下，尤其是当各参与方的请求差异较小时，会造成不必要的资源消耗。本文提出 Slim-ABC，一种新颖的原子广播协议，它消除了传统原子广播协议中 $O(ln^2 + \lambda n^3 \log n)$ 项。尽管 Slim-ABC 减少了被接受的请求数量，但它显著减轻了资源浪费，从而提高了效率。该协议利用异步公共子集和可证明广播机制，实现了 $O(ln^2 + \lambda n^2)$ 的通信复杂度。尽管在接受请求方面存在权衡，Slim-ABC 通过仅允许一部分（$f+1$）参与方广播请求，保持了强大的安全性。我们对 Slim-ABC 进行了全面的效率分析，评估了其在消息复杂度、通信复杂度和时间复杂度等关键指标上的性能。此外，我们提供了严格的安全性分析，证明 Slim-ABC 满足异步公共子集协议的 \textit{一致性}、\textit{有效性} 和 \textit{完整性} 属性。