Offering an architecture for social networking in which people have agency over their personal information and social graph is an open challenge. Here we present a grassroots architecture for serverless, permissionless, peer-to-peer social networks termed Grassroots Social Networking that aims to address this challenge. The architecture is geared for people with networked smartphones -- roaming (address-changing) computing devices communicating over an unreliable network (e.g., using UDP). The architecture incorporates (i) a decentralized social graph, where each person controls, maintains and stores only their local neighborhood in the graph; (iii) personal feeds, with authors and followers who create and store the feeds; and (ii) a grassroots dissemination protocol, in which communication among people occurs only along the edges of their social graph. The architecture realizes these components using the blocklace data structure -- a partially-ordered conflict-free counterpart of the totally-ordered conflict-based blockchain. We provide two example Grassroots Social Networking protocols -- Twitter-like and WhatsApp-like -- and address their security (safety, liveness and privacy), spam/bot/deep-fake resistance, and implementation, demonstrating how server-based social networks could be supplanted by a grassroots architecture.

翻译：构建一种让用户能够自主掌控其个人信息与社交图谱的社交网络架构是一项开放性挑战。本文提出一种名为"草根社交网络"的架构——一种去服务器化、无需许可的点对点社交网络架构，旨在解决该挑战。该架构面向使用联网智能手机（具有地址变更特性的漫游计算设备）的用户，这些设备需通过不可靠网络（例如UDP协议）进行通信。架构包含三大核心组件：(i) 去中心化社交图谱，每位用户仅控制、维护并存储其在本图谱中的局部邻居关系；(ii) 个人动态流，由创作者与关注者共同生成并存储动态内容；(iii) 草根传播协议，用户间仅沿社交图谱的边进行通信。该架构采用块花数据结构实现上述组件——这是一种基于偏序的无冲突数据结构，与基于全序的冲突型区块链形成对照。我们提供两个草根社交网络协议实例（Twitter类与WhatsApp类），并阐述其安全性（安全性、活性与隐私性）、抗垃圾信息/僵尸账号/深度伪造能力以及具体实现方案，论证了基于服务器的社交网络如何被草根架构所取代。