Migrate to ff revision with trait constants

Cargo.toml

@@ -74,4 +74,4 @@ uninline-portable = []
 serde = ["hex", "serde_crate"]
 
 [patch.crates-io]
-ff = { git = "https://github.com/zkcrypto/ff.git", rev = "9a844a72d30ea9f859cd46dcc2237a1ae3277ddc" }
+ff = { git = "https://github.com/zkcrypto/ff.git", rev = "c070ffbaea8cb17e57f817a91ed0e364ff679b7c" }

src/arithmetic/fields.rs

@@ -36,7 +36,7 @@ pub trait FieldExt: ff::PrimeField + From<bool> + Ord + Group<Scalar = Self> {
     /// Modulus of the field written as a string for display purposes
     const MODULUS: &'static str;
 
-    /// Inverse of `PrimeField::root_of_unity()`
+    /// Inverse of `PrimeField::ROOT_OF_UNITY`
     const ROOT_OF_UNITY_INV: Self;
 
     /// Generator of the $t-order$ multiplicative subgroup
@@ -107,10 +107,10 @@ impl<F: FieldExt + SqrtTableHelpers> SqrtTables<F> {
             marker: PhantomData,
         };
 
-        let mut gtab = (0..4).scan(F::root_of_unity(), |gi, _| {
+        let mut gtab = (0..4).scan(F::ROOT_OF_UNITY, |gi, _| {
             // gi == ROOT_OF_UNITY^(256^i)
             let gtab_i: Vec<F> = (0..256)
-                .scan(F::one(), |acc, _| {
+                .scan(F::ONE, |acc, _| {
                     let res = *acc;
                     *acc *= *gi;
                     Some(res)
@@ -205,7 +205,7 @@ impl<F: FieldExt + SqrtTableHelpers> SqrtTables<F> {
 
         let sqdiv = res.square() * div;
         let is_square = (sqdiv - num).is_zero();
-        let is_nonsquare = (sqdiv - F::root_of_unity() * num).is_zero();
+        let is_nonsquare = (sqdiv - F::ROOT_OF_UNITY * num).is_zero();
         assert!(bool::from(
             num.is_zero() | div.is_zero() | (is_square ^ is_nonsquare)
         ));
@@ -222,7 +222,7 @@ impl<F: FieldExt + SqrtTableHelpers> SqrtTables<F> {
 
         let sq = res.square();
         let is_square = (sq - u).is_zero();
-        let is_nonsquare = (sq - F::root_of_unity() * u).is_zero();
+        let is_nonsquare = (sq - F::ROOT_OF_UNITY * u).is_zero();
         assert!(bool::from(u.is_zero() | (is_square ^ is_nonsquare)));
 
         (is_square, res)

src/curves.rs

@@ -897,7 +897,7 @@ macro_rules! impl_projective_curve_ext {
             use super::hashtocurve;
 
             Box::new(move |message| {
-                let mut us = [Field::zero(); 2];
+                let mut us = [Field::ZERO; 2];
                 hashtocurve::hash_to_field($name::CURVE_ID, domain_prefix, message, &mut us);
                 let q0 = hashtocurve::map_to_curve_simple_swu::<$base, $name, $iso>(
                     &us[0],
@@ -1110,7 +1110,7 @@ impl Ep {
         0x4000000000000000,
     ]);
 
-    /// `(F::root_of_unity().invert().unwrap() * z).sqrt().unwrap()`
+    /// `(F::ROOT_OF_UNITY.invert().unwrap() * z).sqrt().unwrap()`
     pub const THETA: Fp = Fp::from_raw([
         0xca330bcc09ac318e,
         0x51f64fc4dc888857,
@@ -1210,7 +1210,7 @@ impl Eq {
         0x4000000000000000,
     ]);
 
-    /// `(F::root_of_unity().invert().unwrap() * z).sqrt().unwrap()`
+    /// `(F::ROOT_OF_UNITY.invert().unwrap() * z).sqrt().unwrap()`
     pub const THETA: Fq = Fq::from_raw([
         0x632cae9872df1b5d,
         0x38578ccadf03ac27,

src/fields/fp.rs

@@ -1,7 +1,7 @@
 use core::fmt;
 use core::ops::{Add, Mul, Neg, Sub};
 
-use ff::PrimeField;
+use ff::{Field, PrimeField};
 use rand::RngCore;
 use subtle::{Choice, ConditionallySelectable, ConstantTimeEq, CtOption};
 
@@ -173,6 +173,18 @@ impl<'a, 'b> Mul<&'b Fp> for &'a Fp {
 impl_binops_additive!(Fp, Fp);
 impl_binops_multiplicative!(Fp, Fp);
 
+impl<T: ::core::borrow::Borrow<Fp>> ::core::iter::Sum<T> for Fp {
+    fn sum<I: Iterator<Item = T>>(iter: I) -> Self {
+        iter.fold(Self::ZERO, |acc, item| acc + item.borrow())
+    }
+}
+
+impl<T: ::core::borrow::Borrow<Fp>> ::core::iter::Product<T> for Fp {
+    fn product<I: Iterator<Item = T>>(iter: I) -> Self {
+        iter.fold(Self::ONE, |acc, item| acc * item.borrow())
+    }
+}
+
 /// INV = -(p^{-1} mod 2^64) mod 2^64
 const INV: u64 = 0x992d30ecffffffff;
 
@@ -481,6 +493,9 @@ impl Group for Fp {
 }
 
 impl ff::Field for Fp {
+    const ZERO: Self = Self::zero();
+    const ONE: Self = Self::one();
+
     fn random(mut rng: impl RngCore) -> Self {
         Self::from_u512([
             rng.next_u64(),
@@ -494,14 +509,6 @@ impl ff::Field for Fp {
         ])
     }
 
-    fn zero() -> Self {
-        Self::zero()
-    }
-
-    fn one() -> Self {
-        Self::one()
-    }
-
     fn double(&self) -> Self {
         self.double()
     }
@@ -575,7 +582,9 @@ impl ff::PrimeField for Fp {
 
     const NUM_BITS: u32 = 255;
     const CAPACITY: u32 = 254;
+    const MULTIPLICATIVE_GENERATOR: Self = GENERATOR;
     const S: u32 = S;
+    const ROOT_OF_UNITY: Self = ROOT_OF_UNITY;
 
     fn from_repr(repr: Self::Repr) -> CtOption<Self> {
         let mut tmp = Fp([0, 0, 0, 0]);
@@ -620,14 +629,6 @@ impl ff::PrimeField for Fp {
     fn is_odd(&self) -> Choice {
         Choice::from(self.to_repr()[0] & 1)
     }
-
-    fn multiplicative_generator() -> Self {
-        GENERATOR
-    }
-
-    fn root_of_unity() -> Self {
-        ROOT_OF_UNITY
-    }
 }
 
 #[cfg(all(feature = "bits", not(target_pointer_width = "64")))]
@@ -796,9 +797,6 @@ impl ec_gpu::GpuField for Fp {
     }
 }
 
-#[cfg(test)]
-use ff::Field;
-
 #[test]
 fn test_inv() {
     // Compute -(r^{-1} mod 2^64) mod 2^64 by exponentiating
@@ -844,8 +842,8 @@ fn test_sqrt_ratio_and_alt() {
     assert!(v_alt == v);
 
     // (false, sqrt(ROOT_OF_UNITY * num/div)), if num and div are nonzero and num/div is a nonsquare in the field
-    let num = num * Fp::root_of_unity();
+    let num = num * Fp::ROOT_OF_UNITY;
-    let expected = Fp::TWO_INV * Fp::root_of_unity() * Fp::from(5).invert().unwrap();
+    let expected = Fp::TWO_INV * Fp::ROOT_OF_UNITY * Fp::from(5).invert().unwrap();
     let (is_square, v) = Fp::sqrt_ratio(&num, &div);
     assert!(!bool::from(is_square));
     assert!(v == expected || (-v) == expected);
@@ -892,14 +890,14 @@ fn test_zeta() {
 #[test]
 fn test_root_of_unity() {
     assert_eq!(
-        Fp::root_of_unity().pow_vartime(&[1 << Fp::S, 0, 0, 0]),
+        Fp::ROOT_OF_UNITY.pow_vartime(&[1 << Fp::S, 0, 0, 0]),
         Fp::one()
     );
 }
 
 #[test]
 fn test_inv_root_of_unity() {
-    assert_eq!(Fp::ROOT_OF_UNITY_INV, Fp::root_of_unity().invert().unwrap());
+    assert_eq!(Fp::ROOT_OF_UNITY_INV, Fp::ROOT_OF_UNITY.invert().unwrap());
 }
 
 #[test]
@@ -912,7 +910,7 @@ fn test_delta() {
     assert_eq!(Fp::DELTA, GENERATOR.pow(&[1u64 << Fp::S, 0, 0, 0]));
     assert_eq!(
         Fp::DELTA,
-        Fp::multiplicative_generator().pow(&[1u64 << Fp::S, 0, 0, 0])
+        Fp::MULTIPLICATIVE_GENERATOR.pow(&[1u64 << Fp::S, 0, 0, 0])
     );
 }
 

src/fields/fq.rs

@@ -1,7 +1,7 @@
 use core::fmt;
 use core::ops::{Add, Mul, Neg, Sub};
 
-use ff::PrimeField;
+use ff::{Field, PrimeField};
 use rand::RngCore;
 use subtle::{Choice, ConditionallySelectable, ConstantTimeEq, CtOption};
 
@@ -173,6 +173,18 @@ impl<'a, 'b> Mul<&'b Fq> for &'a Fq {
 impl_binops_additive!(Fq, Fq);
 impl_binops_multiplicative!(Fq, Fq);
 
+impl<T: ::core::borrow::Borrow<Fq>> ::core::iter::Sum<T> for Fq {
+    fn sum<I: Iterator<Item = T>>(iter: I) -> Self {
+        iter.fold(Self::ZERO, |acc, item| acc + item.borrow())
+    }
+}
+
+impl<T: ::core::borrow::Borrow<Fq>> ::core::iter::Product<T> for Fq {
+    fn product<I: Iterator<Item = T>>(iter: I) -> Self {
+        iter.fold(Self::ONE, |acc, item| acc * item.borrow())
+    }
+}
+
 /// INV = -(q^{-1} mod 2^64) mod 2^64
 const INV: u64 = 0x8c46eb20ffffffff;
 
@@ -481,6 +493,9 @@ impl Group for Fq {
 }
 
 impl ff::Field for Fq {
+    const ZERO: Self = Self::zero();
+    const ONE: Self = Self::one();
+
     fn random(mut rng: impl RngCore) -> Self {
         Self::from_u512([
             rng.next_u64(),
@@ -494,14 +509,6 @@ impl ff::Field for Fq {
         ])
     }
 
-    fn zero() -> Self {
-        Self::zero()
-    }
-
-    fn one() -> Self {
-        Self::one()
-    }
-
     fn double(&self) -> Self {
         self.double()
     }
@@ -575,7 +582,9 @@ impl ff::PrimeField for Fq {
 
     const NUM_BITS: u32 = 255;
     const CAPACITY: u32 = 254;
+    const MULTIPLICATIVE_GENERATOR: Self = GENERATOR;
     const S: u32 = S;
+    const ROOT_OF_UNITY: Self = ROOT_OF_UNITY;
 
     fn from_repr(repr: Self::Repr) -> CtOption<Self> {
         let mut tmp = Fq([0, 0, 0, 0]);
@@ -620,14 +629,6 @@ impl ff::PrimeField for Fq {
     fn is_odd(&self) -> Choice {
         Choice::from(self.to_repr()[0] & 1)
     }
-
-    fn multiplicative_generator() -> Self {
-        GENERATOR
-    }
-
-    fn root_of_unity() -> Self {
-        ROOT_OF_UNITY
-    }
 }
 
 #[cfg(all(feature = "bits", not(target_pointer_width = "64")))]
@@ -795,9 +796,6 @@ impl ec_gpu::GpuField for Fq {
     }
 }
 
-#[cfg(test)]
-use ff::Field;
-
 #[test]
 fn test_inv() {
     // Compute -(r^{-1} mod 2^64) mod 2^64 by exponentiating
@@ -843,8 +841,8 @@ fn test_sqrt_ratio_and_alt() {
     assert!(v_alt == v);
 
     // (false, sqrt(ROOT_OF_UNITY * num/div)), if num and div are nonzero and num/div is a nonsquare in the field
-    let num = num * Fq::root_of_unity();
+    let num = num * Fq::ROOT_OF_UNITY;
-    let expected = Fq::TWO_INV * Fq::root_of_unity() * Fq::from(5).invert().unwrap();
+    let expected = Fq::TWO_INV * Fq::ROOT_OF_UNITY * Fq::from(5).invert().unwrap();
     let (is_square, v) = Fq::sqrt_ratio(&num, &div);
     assert!(!bool::from(is_square));
     assert!(v == expected || (-v) == expected);
@@ -890,14 +888,14 @@ fn test_zeta() {
 #[test]
 fn test_root_of_unity() {
     assert_eq!(
-        Fq::root_of_unity().pow_vartime(&[1 << Fq::S, 0, 0, 0]),
+        Fq::ROOT_OF_UNITY.pow_vartime(&[1 << Fq::S, 0, 0, 0]),
         Fq::one()
     );
 }
 
 #[test]
 fn test_inv_root_of_unity() {
-    assert_eq!(Fq::ROOT_OF_UNITY_INV, Fq::root_of_unity().invert().unwrap());
+    assert_eq!(Fq::ROOT_OF_UNITY_INV, Fq::ROOT_OF_UNITY.invert().unwrap());
 }
 
 #[test]
@@ -910,7 +908,7 @@ fn test_delta() {
     assert_eq!(Fq::DELTA, GENERATOR.pow(&[1u64 << Fq::S, 0, 0, 0]));
     assert_eq!(
         Fq::DELTA,
-        Fq::multiplicative_generator().pow(&[1u64 << Fq::S, 0, 0, 0])
+        Fq::MULTIPLICATIVE_GENERATOR.pow(&[1u64 << Fq::S, 0, 0, 0])
     );
 }
 

src/hashtocurve.rs

@@ -136,7 +136,7 @@ pub fn map_to_curve_simple_swu<F: FieldExt, C: CurveExt<Base = F>, I: CurveExt<B
     let b = I::b();
     let z_u2 = z * u.square();
     let ta = z_u2.square() + z_u2;
-    let num_x1 = b * (ta + F::one());
+    let num_x1 = b * (ta + F::ONE);
     let div = a * F::conditional_select(&-ta, &z, ta.is_zero());
     let num2_x1 = num_x1.square();
     let div2 = div.square();