Algebraic Replicated Data Types: Programming Secure Local-First Software (Artifact)

Abstract

This work is about programming support for local-first applications that manage private data locally, but still synchronize data between multiple devices. Typical use cases are synchronizing settings and data, and collaboration between multiple users. Such applications must preserve the privacy and integrity of the user’s data without impeding or interrupting the user’s normal workflow - even when the device is offline or has a flaky network connection.
From the programming perspective, availability along with privacy and security concerns pose significant challenges, for which developers have to learn and use specialized solutions such as conflict-free replicated data types (CRDTs) or APIs for centralized data stores. This work relieves developers from this complexity by enabling the direct and automatic use of algebraic data types - which developers already use to express the business logic of the application - for synchronization and collaboration. Moreover, we use this approach to provide end-to-end encryption and authentication between multiple replicas (using a shared secret) that is suitable for a coordination-free setting.
This artifact demonstrates the approach in the context of a realistic case study. It shows that an implementation of the approach can handle realistic workloads, that the size of the data types does not grow indefinitely, and that it is feasible to always enable encryption for the intended scenario.