More Note refinements

zebra-chain/src/notes/sapling.rs

@@ -40,6 +40,10 @@ impl ZcashSerialize for Nullifier {
     }
 }
 
+/// The randomness used in the Pedersen Hash for note commitment.
+#[derive(Copy, Clone, Debug, PartialEq)]
+pub struct NoteCommitmentRandomness(redjubjub::Randomizer);
+
 /// A Note represents that a value is spendable by the recipient who
 /// holds the spending key corresponding to a given shielded payment
 /// address.
@@ -53,8 +57,7 @@ pub struct Note {
 /// The decrypted form of encrypted Sapling notes on the blockchain.
 pub struct NotePlaintext {
     diversifier: Diversifier,
-    value: u64,
+    value: Amount<NonNegative>,
-    // TODO: refine as jub-jub appropriate in the base field.
     note_commitment_randomness: NoteCommitmentRandomness,
     memo: memo::Memo,
 }

zebra-chain/src/notes/sprout.rs

@@ -53,6 +53,16 @@ impl ZcashSerialize for Nullifier {
     }
 }
 
+/// The randomness used in the Pedersen Hash for note commitment.
+#[derive(Copy, Clone, Debug, PartialEq)]
+pub struct NoteCommitmentRandomness(pub [u8; 32]);
+
+impl AsRef<[u8]> for NoteCommitmentRandomness {
+    fn as_ref(&self) -> &[u8] {
+        &self.0
+    }
+}
+
 /// A Note represents that a value is spendable by the recipient who
 /// holds the spending key corresponding to a given shielded payment
 /// address.