The data availability problem is a central challenge in blockchain systems and lies at the core of the accessibility and scalability issues faced by platforms such as Ethereum. Modern solutions employ several approaches, with data availability sampling (DAS) being the most self-sufficient and minimalistic in its security assumptions. Existing DAS methods typically form cryptographic commitments on codewords of fixed-rate erasure codes, which restrict light nodes to sampling from a predetermined set of coded symbols. In this paper, we introduce a new approach to DAS that modularizes the coding and commitment process by committing to the uncoded data while performing sampling through on-the-fly coding. The resulting samples are significantly more expressive, enabling light nodes to obtain, in concrete implementations, up to multiple orders of magnitude stronger assurances of data availability than from sampling pre-committed symbols from a fixed-rate redundancy code as done in established DAS schemes using Reed Solomon or low density parity check codes. We present a concrete protocol that realizes this paradigm using random linear network coding (RLNC).

翻译：数据可用性问题一直是区块链系统中的核心挑战，也是以太坊等平台面临的可访问性与可扩展性问题的根源。现有解决方案采用多种方法，其中数据可用性采样（DAS）因其安全假设最具自足性与极简性而成为主流。现有DAS方法通常对固定速率纠删码的码字建立密码学承诺，这使得轻节点只能从预设的编码符号集合中采样。本文提出了一种新型DAS方法，通过将编码与承诺过程模块化——即对未编码数据作出承诺，并利用实时编码进行采样。所得采样结果具有显著更强的表达能力，在具体实现中，轻节点可获得的数据可用性保证强度比采用Reed Solomon或低密度奇偶校验码等固定速率冗余码进行预承诺符号采样的传统DAS方案高出多个数量级。我们提出了一个采用随机线性网络编码（RLNC）实现该范式的具体协议。