The prior `SpendAuth` and `Binding` enums have been renamed to
`sapling::{SpendAuth, Binding}`. These might subsequently be removed
from the crate entirely (moving into a wrapping `redjubjub` crate).
The code assumes that scalar and point representations are [u8; 32],
which will be the case for all curves we instantiate RedDSA with for
Zcash.
Also use fully secure ChaChaRng with a full seed, not just a u64.
Now that we always generate an extra proper VerificationKey for each
Tweak::ChangePubkey case, this /should/ never fail: it also helps split out the
actual verification of the signature from the parsing and validation of the key
itself.
The `SpendAuth` test vectors were generated using
`FixedGenerators::SpendingKeyGenerator`, and the `Binding` test vectors
were generated using `FixedGenerators::ValueCommitmentRandomness`.
Tomas Krnak
Jack Grigg
Deirdre Connolly
Deirdre Connolly
Henry de Valence