发表机构
Mysten Labs（Mysten Labs）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
Physalia通过秘密共享数据本身而非仅密钥，将去中心化存储中泄露内容所需的重分发带宽提升至数据大小，并引入鲁棒性变换抵御损坏共享，实现端到端访问控制。
AI 中文摘要
在去中心化存储系统中，访问控制通常通过在上传前加密数据并将解密密钥与授权方共享来实现。然而，一旦密钥泄露，数据便公开可访问，这降低了内容盗版的门槛，低于传统系统——在传统系统中，盗版需要重新分发完整数据。我们提出Physalia，一个面向去中心化存储的端到端访问控制系统，它对数据本身而非仅密钥进行秘密共享，并将共享分发到多个服务器。因此，泄露数据需要完整传输数据：我们形式化这一直觉，并引入对手为泄露受保护内容必须支付的重分发带宽，证明Physalia将其提升至数据大小。跨不可信服务器共享需要对抗损坏共享的鲁棒性。我们开发了一种鲁棒性变换，将任何计算性秘密共享方案转变为鲁棒方案，该变换具有独立的研究价值。与依赖纠错码的现有方案不同，它使用带临时密钥的签名，并且每个共享仅增加常量大小的元数据。我们证明该变换是安全的，并在Walrus去中心化存储系统上使用链上访问策略对Physalia进行端到端评估。
英文摘要
In decentralized storage systems, access control is often implemented by encrypting the data before upload and sharing the decryption key with authorized parties. A leaked key, however, makes the data publicly accessible, which lowers the barrier to content piracy below that of traditional systems, where piracy requires redistributing the full data. We present Physalia, an end-to-end access-control system for decentralized storage that secret-shares the data itself, instead of just the key, across multiple servers. Leaking the data then requires transmitting it in full: We formalize this intuition and introduce the redistribution bandwidth an adversary must pay to leak protected content and show that Physalia raises it to the size of the data. Sharing across untrusted servers requires robustness against corrupted shares. We develop a robustness transform that turns any computational secret sharing scheme into a robust one and which is of independent interest. In contrast to existing schemes that rely on error correction, it uses signatures with ephemeral keys and adds only constant-size metadata per share. We show that this transform is secure and evaluate Physalia end-to-end on the Walrus decentralized storage system with an on-chain access policy.
