Relationship-Based Access Control (ReBAC)
An access model where permission comes from a relationship between subject and resource — often walked through a graph — rather than a role or a static attribute, the model Google Zanzibar popularized.
aka: ReBAC
ReBAC answers the question earlier models kept dodging: access that depends on how two specific things relate to each other, computed by traversing a graph of relationship tuples rather than evaluating a rule in isolation. It’s the model behind sharing features in tools like Google Drive, and the one coarser models reach for once “shared with my team” or “owned by me” access shows up.