From b4feff82728d09fb5b816b4eae5257cf84dc94c5 Mon Sep 17 00:00:00 2001
From: Jack Grigg <jack@electriccoin.co>
Date: Thu, 25 Feb 2021 18:17:50 +0000
Subject: [PATCH] Remove ECC gadgets and instructions

Migrated to the orchard crate:
https://github.com/zcash/orchard/pull/22
---
 src/gadget.rs     |   1 -
 src/gadget/ecc.rs | 140 ----------------------------------------------
 2 files changed, 141 deletions(-)
 delete mode 100644 src/gadget/ecc.rs

diff --git a/src/gadget.rs b/src/gadget.rs
index 4b4b1cf140..ccf8512671 100644
--- a/src/gadget.rs
+++ b/src/gadget.rs
@@ -1,4 +1,3 @@
 //! Self-contained circuit implementations of various primitives.
 
-pub mod ecc;
 pub mod sha256;
diff --git a/src/gadget/ecc.rs b/src/gadget/ecc.rs
deleted file mode 100644
index d9a9d743ad..0000000000
--- a/src/gadget/ecc.rs
+++ /dev/null
@@ -1,140 +0,0 @@
-//! Gadgets and chips for elliptic curve operations.
-
-use std::fmt;
-
-use crate::{
-    arithmetic::CurveAffine,
-    circuit::{Chip, Layouter},
-    plonk::Error,
-};
-
-/// Trait allowing circuit's fixed points to be enumerated.
-pub trait FixedPoints<C: CurveAffine>: Clone + fmt::Debug {}
-
-/// The set of circuit instructions required to use the ECC gadgets.
-pub trait EccInstructions<C: CurveAffine>: Chip<Field = C::Base> {
-    /// Variable representing an element of the elliptic curve's scalar field.
-    type Scalar: Clone + fmt::Debug;
-    /// Variable representing an elliptic curve point.
-    type Point: Clone + fmt::Debug;
-    /// Variable representing the set of fixed bases in the circuit.
-    type FixedPoints: FixedPoints<C>;
-    /// Variable representing a fixed elliptic curve point (constant in the circuit).
-    type FixedPoint: Clone + fmt::Debug;
-
-    /// Witnesses the given scalar as a private input to the circuit.
-    fn witness_scalar(
-        layouter: &mut impl Layouter<Self>,
-        value: Option<C::Scalar>,
-    ) -> Result<Self::Scalar, Error>;
-
-    /// Witnesses the given point as a private input to the circuit.
-    fn witness_point(
-        layouter: &mut impl Layouter<Self>,
-        value: Option<C>,
-    ) -> Result<Self::Point, Error>;
-
-    /// Gets a fixed point into the circuit.
-    fn get_fixed(
-        layouter: &mut impl Layouter<Self>,
-        fixed_points: Self::FixedPoints,
-    ) -> Result<Self::FixedPoint, Error>;
-
-    /// Performs point addition, returning `a + b`.
-    fn add(
-        layouter: &mut impl Layouter<Self>,
-        a: &Self::Point,
-        b: &Self::Point,
-    ) -> Result<Self::Point, Error>;
-
-    /// Performs point doubling, returning `[2] a`.
-    fn double(layouter: &mut impl Layouter<Self>, a: &Self::Point) -> Result<Self::Point, Error>;
-
-    /// Performs variable-base scalar multiplication, returning `[scalar] base`.
-    fn mul(
-        layouter: &mut impl Layouter<Self>,
-        scalar: &Self::Scalar,
-        base: &Self::Point,
-    ) -> Result<Self::Point, Error>;
-
-    /// Performs fixed-base scalar multiplication, returning `[scalar] base`.
-    fn mul_fixed(
-        layouter: &mut impl Layouter<Self>,
-        scalar: &Self::Scalar,
-        base: &Self::FixedPoint,
-    ) -> Result<Self::Point, Error>;
-}
-
-/// An element of the given elliptic curve's scalar field.
-#[derive(Debug)]
-pub struct Scalar<C: CurveAffine, EccChip: EccInstructions<C>> {
-    inner: EccChip::Scalar,
-}
-
-impl<C: CurveAffine, EccChip: EccInstructions<C>> Scalar<C, EccChip> {
-    /// Constructs a new point with the given value.
-    pub fn new(
-        mut layouter: impl Layouter<EccChip>,
-        value: Option<C::Scalar>,
-    ) -> Result<Self, Error> {
-        EccChip::witness_scalar(&mut layouter, value).map(|inner| Scalar { inner })
-    }
-}
-
-/// An elliptic curve point over the given curve.
-#[derive(Debug)]
-pub struct Point<C: CurveAffine, EccChip: EccInstructions<C>> {
-    inner: EccChip::Point,
-}
-
-impl<C: CurveAffine, EccChip: EccInstructions<C>> Point<C, EccChip> {
-    /// Constructs a new point with the given value.
-    pub fn new(mut layouter: impl Layouter<EccChip>, value: Option<C>) -> Result<Self, Error> {
-        EccChip::witness_point(&mut layouter, value).map(|inner| Point { inner })
-    }
-
-    /// Returns `self + other`.
-    pub fn add(&self, mut layouter: impl Layouter<EccChip>, other: &Self) -> Result<Self, Error> {
-        EccChip::add(&mut layouter, &self.inner, &other.inner).map(|inner| Point { inner })
-    }
-
-    /// Returns `[2] self`.
-    pub fn double(&self, mut layouter: impl Layouter<EccChip>) -> Result<Self, Error> {
-        EccChip::double(&mut layouter, &self.inner).map(|inner| Point { inner })
-    }
-
-    /// Returns `[by] self`.
-    pub fn mul(
-        &self,
-        mut layouter: impl Layouter<EccChip>,
-        by: &Scalar<C, EccChip>,
-    ) -> Result<Self, Error> {
-        EccChip::mul(&mut layouter, &by.inner, &self.inner).map(|inner| Point { inner })
-    }
-}
-
-/// A constant elliptic curve point over the given curve, for which scalar multiplication
-/// is more efficient.
-#[derive(Debug)]
-pub struct FixedPoint<C: CurveAffine, EccChip: EccInstructions<C>> {
-    inner: EccChip::FixedPoint,
-}
-
-impl<C: CurveAffine, EccChip: EccInstructions<C>> FixedPoint<C, EccChip> {
-    /// Gets a reference to the specified fixed point in the circuit.
-    pub fn get(
-        mut layouter: impl Layouter<EccChip>,
-        point: EccChip::FixedPoints,
-    ) -> Result<Self, Error> {
-        EccChip::get_fixed(&mut layouter, point).map(|inner| FixedPoint { inner })
-    }
-
-    /// Returns `[by] self`.
-    pub fn mul(
-        &self,
-        mut layouter: impl Layouter<EccChip>,
-        by: &Scalar<C, EccChip>,
-    ) -> Result<Point<C, EccChip>, Error> {
-        EccChip::mul_fixed(&mut layouter, &by.inner, &self.inner).map(|inner| Point { inner })
-    }
-}