Data Availability Sampling (DAS), a central component of Ethereum's roadmap, enables clients to verify data availability without requiring any single client to download the entire dataset. DAS operates by having clients randomly retrieve individual symbols of erasure-encoded data from a peer-to-peer network. While the cryptographic and encoding aspects of DAS have recently undergone formal analysis, the peer-to-peer networking layer remains underexplored, with a lack of security definitions and efficient, provably secure constructions. In this work, we address this gap by introducing a novel distributed data structure that can serve as the networking layer for DAS, which we call robust distributed arrays. That is, we rigorously define a robustness property of a distributed data structure in an open permissionless network, that mimics a collection of arrays. Then, we give a simple and efficient construction and formally prove its robustness. Notably, every individual node is required to store only small portions of the data, and accessing array positions incurs minimal latency. The robustness of our construction relies solely on the presence of a minimal absolute number of honest nodes in the network. In particular, we avoid any honest majority assumption. Beyond DAS, we anticipate that robust distributed arrays can have wider applications in distributed systems.

翻译：数据可用性采样（DAS）是以太坊路线图的核心组件，它使客户端能够验证数据可用性，而无需任何单个客户端下载完整数据集。DAS通过让客户端从点对点网络中随机检索纠删编码数据的单个符号来运行。尽管DAS的密码学与编码方面近期已得到形式化分析，但其点对点网络层仍缺乏深入研究，既缺少安全定义，也缺乏高效且可证明安全的构造。本工作通过引入一种新型分布式数据结构来填补这一空白，该结构可作为DAS的网络层，我们称之为鲁棒分布式数组。具体而言，我们在开放无许可网络中严格定义了模拟数组集合的分布式数据结构鲁棒性属性，随后给出一种简洁高效的构造并形式化证明其鲁棒性。值得注意的是，每个独立节点仅需存储数据的极小部分，且访问数组位置产生的延迟极低。我们构造的鲁棒性仅依赖于网络中诚实节点存在最小绝对数量，特别地，我们避免了任何诚实多数假设。除DAS外，我们预期鲁棒分布式数组在分布式系统中具有更广泛的应用前景。