This is the core API for interacting with transactions and the chain. It's essentially a facade to a lot of different projects.
This is the only Iron Fish project that knows about the Sapling API and its zero-knowledge proving mechanism.
There are theoretically different kinds of elliptical curves that can be used with Sapling, but we are currently depending on the BLS12 curve. Everything in ironfish-rust is parameterized on the curve type, but there are easy facades exported from sapling::bls12 for the different struct types.
This layer is tangentially aware of the chain. It is not aware of the peer-to-peer network or client APIs.