//! Sprout key types.
//!
//! Unused key types are not implemented, see PR #5476.
//!
//! "The receiving key sk_enc, the incoming viewing key ivk = (apk,
//! sk_enc), and the shielded payment address addr_pk = (a_pk, pk_enc) are
//! derived from a_sk, as described in ['Sprout Key Components'][ps]
//!
//! [ps]: https://zips.z.cash/protocol/protocol.pdf#sproutkeycomponents
use fmt;
/// A Sprout _paying key_.
///
/// Derived from a Sprout _spending key.
;