On Extend-Only Directed Posets and Derived Byzantine-Tolerant Replicated Data Types (Extended Version)

We uncover the extend-only directed posets (EDP) structure as a unification of recently discussed DAG-based Byzantine-tolerant conflict-free replicated data types (CRDT). We also show how a key-value map model can be derived from the EDP formulation, and give an outlook on an EDP-based systemic access control CRDT as a formalization of the CRDT used in the Matrix messaging system.