From c4bf8105f2d0d16372567ebf91b37de9519c3479 Mon Sep 17 00:00:00 2001
From: Jack Grigg <jack@electriccoin.co>
Date: Tue, 3 May 2022 20:26:41 +0000
Subject: [PATCH] Use `AssignedCell<NoteValue, _>` for circuit note values

---
 src/circuit.rs             |  4 ++--
 src/circuit/note_commit.rs | 21 ++++++++++++---------
 src/value.rs               |  7 +++++++
 3 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/src/circuit.rs b/src/circuit.rs
index 6cf58e11..7aeb77f8 100644
--- a/src/circuit.rs
+++ b/src/circuit.rs
@@ -377,14 +377,14 @@ impl plonk::Circuit<pallas::Base> for Circuit {
             let v_old = assign_free_advice(
                 layouter.namespace(|| "witness v_old"),
                 config.advices[0],
-                self.v_old.map(|v_old| pallas::Base::from(v_old.inner())),
+                self.v_old,
             )?;
 
             // Witness v_new.
             let v_new = assign_free_advice(
                 layouter.namespace(|| "witness v_new"),
                 config.advices[0],
-                self.v_new.map(|v_new| pallas::Base::from(v_new.inner())),
+                self.v_new,
             )?;
 
             (psi_old, rho_old, cm_old, g_d_old, ak_P, nk, v_old, v_new)
diff --git a/src/circuit/note_commit.rs b/src/circuit/note_commit.rs
index d98bf0d6..e61735f6 100644
--- a/src/circuit/note_commit.rs
+++ b/src/circuit/note_commit.rs
@@ -7,7 +7,10 @@ use halo2_proofs::{
 };
 use pasta_curves::{arithmetic::FieldExt, pallas};
 
-use crate::constants::{OrchardCommitDomains, OrchardFixedBases, OrchardHashDomains, T_P};
+use crate::{
+    constants::{OrchardCommitDomains, OrchardFixedBases, OrchardHashDomains, T_P},
+    value::NoteValue,
+};
 use halo2_gadgets::{
     ecc::{
         chip::{EccChip, NonIdentityEccPoint},
@@ -550,8 +553,7 @@ impl NoteCommitConfig {
         ecc_chip: EccChip<OrchardFixedBases>,
         g_d: &NonIdentityEccPoint,
         pk_d: &NonIdentityEccPoint,
-        // TODO: Set V to Orchard value type
-        value: AssignedCell<pallas::Base, pallas::Base>,
+        value: AssignedCell<NoteValue, pallas::Base>,
         rho: AssignedCell<pallas::Base, pallas::Base>,
         psi: AssignedCell<pallas::Base, pallas::Base>,
         rcm: Option<pallas::Scalar>,
@@ -560,7 +562,7 @@ impl NoteCommitConfig {
         let (pkd_x, pkd_y) = (pk_d.x(), pk_d.y());
         let (gd_x, gd_y) = (gd_x.value(), gd_y.value());
         let (pkd_x, pkd_y) = (pkd_x.value(), pkd_y.value());
-        let value_val = value.value();
+        let value_val = value.value().map(|v| pallas::Base::from(v.inner()));
         let rho_val = rho.value();
         let psi_val = psi.value();
 
@@ -621,12 +623,12 @@ impl NoteCommitConfig {
             let d_2 = RangeConstrained::witness_short(
                 &self.sinsemilla_config.lookup_config(),
                 layouter.namespace(|| "d_2"),
-                value_val,
+                value_val.as_ref(),
                 0..8,
             )?;
 
             // d_3 = z1_d from the SinsemillaHash(d) running sum output.
-            let d_3 = RangeConstrained::subset_of(value_val, 8..58);
+            let d_3 = RangeConstrained::subset_of(value_val.as_ref(), 8..58);
 
             let d = MessagePiece::from_subpieces(
                 chip.clone(),
@@ -643,7 +645,7 @@ impl NoteCommitConfig {
             let e_0 = RangeConstrained::witness_short(
                 &self.sinsemilla_config.lookup_config(),
                 layouter.namespace(|| "e_0"),
-                value_val,
+                value_val.as_ref(),
                 58..64,
             )?;
 
@@ -1466,7 +1468,7 @@ struct GateCells {
     h_1: RangeConstrained<pallas::Base, Option<pallas::Base>>,
     gd_x: AssignedCell<pallas::Base, pallas::Base>,
     pkd_x: AssignedCell<pallas::Base, pallas::Base>,
-    value: AssignedCell<pallas::Base, pallas::Base>,
+    value: AssignedCell<NoteValue, pallas::Base>,
     rho: AssignedCell<pallas::Base, pallas::Base>,
     psi: AssignedCell<pallas::Base, pallas::Base>,
     a_prime: AssignedCell<pallas::Base, pallas::Base>,
@@ -1494,6 +1496,7 @@ mod tests {
             fixed_bases::NOTE_COMMITMENT_PERSONALIZATION, OrchardCommitDomains, OrchardFixedBases,
             OrchardHashDomains, L_ORCHARD_BASE, L_VALUE, T_Q,
         },
+        value::NoteValue,
     };
     use halo2_gadgets::{
         ecc::{
@@ -1665,7 +1668,7 @@ mod tests {
                 // A note value cannot be negative.
                 let value = {
                     let mut rng = OsRng;
-                    pallas::Base::from(rng.next_u64())
+                    NoteValue::from_raw(rng.next_u64())
                 };
                 let value_var = {
                     assign_free_advice(
diff --git a/src/value.rs b/src/value.rs
index 751a80e6..38db80c9 100644
--- a/src/value.rs
+++ b/src/value.rs
@@ -42,6 +42,7 @@ use core::ops::{Add, RangeInclusive, Sub};
 use bitvec::{array::BitArray, order::Lsb0};
 use ff::{Field, PrimeField};
 use group::{Curve, Group, GroupEncoding};
+use halo2_proofs::plonk::Assigned;
 use pasta_curves::{
     arithmetic::{CurveAffine, CurveExt},
     pallas,
@@ -115,6 +116,12 @@ impl NoteValue {
     }
 }
 
+impl From<&NoteValue> for Assigned<pallas::Base> {
+    fn from(v: &NoteValue) -> Self {
+        pallas::Base::from(v.inner()).into()
+    }
+}
+
 impl Sub for NoteValue {
     type Output = ValueSum;