Deterministic State Access Restrictions (IPLD Reachability)

[Stebalien]

This FIP brings us a step closer to user-defined WebAssembly actors by introducing deterministic rules defining what "state" (IPLD blocks) an actor is and is not allowed to read. Specifically, this FIP specifies that an actor may only read state "reachable" from:

1. The actor's state-tree.
2. Parameters passed into the actor from other actors.
3. Blocks returned to the actor from other actors.

Where "reachable" means that the state can be "reached" by traversing IPLD links (CIDs) from the "roots" listed above.

FIP
Draft Implementation