Implement CurveExt::hash_to_curve for {bn256::G1,grumpkin::G1}

.github/workflows/ci.yml

@@ -13,17 +13,11 @@ jobs:
     strategy:
       matrix:
         include:
-          - rust: 1.63.0
-            feature: default
-          - rust: nightly
-            feature: asm
-
+          - feature: default
+          - feature: asm
     steps:
       - uses: actions/checkout@v2
       - uses: actions-rs/toolchain@v1
-        with:
-          override: true
-          toolchain: ${{ matrix.rust }}
       - name: Build
         uses: actions-rs/cargo@v1
         with:
@@ -37,17 +31,11 @@ jobs:
     strategy:
       matrix:
         include:
-          - rust: 1.63.0
-            feature: default
-          - rust: nightly
-            feature: asm
-
+          - feature: default
+          - feature: asm
     steps:
       - uses: actions/checkout@v2
       - uses: actions-rs/toolchain@v1
-        with:
-          override: true
-          toolchain: ${{ matrix.rust }}
       - name: Test
         uses: actions-rs/cargo@v1
         with:
@@ -79,8 +67,6 @@ jobs:
       - uses: actions/checkout@v2
       - uses: actions-rs/toolchain@v1
         with:
-          override: true
-          toolchain: nightly
           components: clippy
       - name: Run clippy
         uses: actions-rs/cargo@v1
@@ -96,9 +82,6 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - uses: actions-rs/toolchain@v1
-        with:
-          override: true
-          toolchain: nightly
       - name: Bench arithmetic
         uses: actions-rs/cargo@v1
         with:

Cargo.toml

@@ -33,6 +33,7 @@ num-traits = "0.2"
 paste = "1.0.11"
 serde = { version = "1.0", default-features = false, optional = true }
 serde_arrays = { version = "0.1.0", optional = true }
+blake2b_simd = "1"
 
 [features]
 default = ["reexport", "bits"]

src/bn256/curve.rs

@@ -10,6 +10,7 @@ use crate::ff::WithSmallOrderMulGroup;
 use crate::ff::{Field, PrimeField};
 use crate::group::Curve;
 use crate::group::{cofactor::CofactorGroup, prime::PrimeCurveAffine, Group, GroupEncoding};
+use crate::hash_to_curve::svdw_hash_to_curve;
 use crate::{
     batch_add, impl_add_binop_specify_output, impl_binops_additive,
     impl_binops_additive_specify_output, impl_binops_multiplicative,
@@ -38,6 +39,7 @@ new_curve_impl!(
     G1_A,
     G1_B,
     "bn256_g1",
+    |curve_id, domain_prefix| svdw_hash_to_curve(curve_id, domain_prefix, G1::SVDW_Z),
 );
 
 new_curve_impl!(
@@ -51,6 +53,7 @@ new_curve_impl!(
     G2_A,
     G2_B,
     "bn256_g2",
+    |_, _| unimplemented!(),
 );
 
 impl CurveAffineExt for G1Affine {
@@ -212,17 +215,76 @@ impl CofactorGroup for G2 {
     }
 }
 
+impl G1 {
+    const SVDW_Z: Fq = Fq::ONE;
+}
+
 #[cfg(test)]
 mod tests {
-
     use crate::arithmetic::CurveEndo;
     use crate::bn256::{Fr, G1, G2};
     use crate::CurveExt;
     use ff::Field;
-    use ff::PrimeField;
-    use ff::WithSmallOrderMulGroup;
+    use ff::{PrimeField, WithSmallOrderMulGroup};
     use rand_core::OsRng;
 
+    #[test]
+    fn test_hash_to_curve() {
+        crate::tests::curve::hash_to_curve_test::<G1>();
+    }
+
+    #[test]
+    fn test_map_to_curve() {
+        crate::tests::curve::svdw_map_to_curve_test::<G1>(
+            G1::SVDW_Z,
+            // Precomputed constants taken from https://github.com/ConsenSys/gnark-crypto/blob/441dc0ffe639294b8d09e394f24ba7575577229c/internal/generator/config/bn254.go#L26-L32.
+            [
+                "4",
+                "10944121435919637611123202872628637544348155578648911831344518947322613104291",
+                "8815841940592487685674414971303048083897117035520822607866",
+                "7296080957279758407415468581752425029565437052432607887563012631548408736189",
+            ],
+            // List of (u, (Q.x, Q.y)) taken from https://github.com/ConsenSys/gnark-crypto/blob/441dc0ffe639294b8d09e394f24ba7575577229c/ecc/bn254/hash_vectors_test.go#L4-L28
+            [
+                (
+                    "0xcb81538a98a2e3580076eed495256611813f6dae9e16d3d4f8de7af0e9833e1",
+                    (
+                        "0x1bb8810e2ceaf04786d4efd216fc2820ddd9363712efc736ada11049d8af5925",
+                        "0x1efbf8d54c60d865cce08437668ea30f5bf90d287dbd9b5af31da852915e8f11",
+                    ),
+                ),
+                (
+                    "0xba35e127276e9000b33011860904ddee28f1d48ddd3577e2a797ef4a5e62319",
+                    (
+                        "0xda4a96147df1f35b0f820bd35c6fac3b80e8e320de7c536b1e054667b22c332",
+                        "0x189bd3fbffe4c8740d6543754d95c790e44cd2d162858e3b733d2b8387983bb7",
+                    ),
+                ),
+                (
+                    "0x11852286660cd970e9d7f46f99c7cca2b75554245e91b9b19d537aa6147c28fc",
+                    (
+                        "0x2ff727cfaaadb3acab713fa22d91f5fddab3ed77948f3ef6233d7ea9b03f4da1",
+                        "0x304080768fd2f87a852155b727f97db84b191e41970506f0326ed4046d1141aa",
+                    ),
+                ),
+                (
+                    "0x174d1c85d8a690a876cc1deba0166d30569fafdb49cb3ed28405bd1c5357a1cc",
+                    (
+                        "0x11a2eaa8e3e89de056d1b3a288a7f733c8a1282efa41d28e71af065ab245df9b",
+                        "0x60f37c447ac29fd97b9bb83be98ddccf15e34831a9cdf5493b7fede0777ae06",
+                    ),
+                ),
+                (
+                    "0x73b81432b4cf3a8a9076201500d1b94159539f052a6e0928db7f2df74bff672",
+                    (
+                        "0x27409dccc6ee4ce90e24744fda8d72c0bc64e79766f778da0c1c0ef1c186ea84",
+                        "0x1ac201a542feca15e77f30370da183514dc99d8a0b2c136d64ede35cd0b51dc0",
+                    ),
+                ),
+            ],
+        );
+    }
+
     #[test]
     fn test_curve() {
         crate::tests::curve::curve_tests::<G1>();

src/bn256/engine.rs

@@ -62,7 +62,7 @@ pub struct Gt(pub(crate) Fq12);
 
 impl std::fmt::Display for Gt {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "{:?}", self)
+        write!(f, "{self:?}")
     }
 }
 

src/bn256/fr.rs

@@ -463,8 +463,8 @@ mod test {
         let mut rng = ark_std::test_rng();
         let base = (0..repeat).map(|_| (rng.next_u32() % (1 << 16)) as u64);
 
-        let timer = start_timer!(|| format!("generate {} Bn256 scalar field elements", repeat));
-        let _res: Vec<_> = base.map(|b| Fr::from(b)).collect();
+        let timer = start_timer!(|| format!("generate {repeat} Bn256 scalar field elements"));
+        let _res: Vec<_> = base.map(Fr::from).collect();
 
         end_timer!(timer);
     }

src/derive/curve.rs

@@ -203,6 +203,7 @@ macro_rules! new_curve_impl {
     $constant_a:expr,
     $constant_b:expr,
     $curve_id:literal,
+    $hash_to_curve:expr,
     ) => {
 
         macro_rules! impl_compressed {
@@ -615,8 +616,8 @@ macro_rules! new_curve_impl {
             }
 
 
-            fn hash_to_curve<'a>(_: &'a str) -> Box<dyn Fn(&[u8]) -> Self + 'a> {
-                unimplemented!();
+            fn hash_to_curve<'a>(domain_prefix: &'a str) -> Box<dyn Fn(&[u8]) -> Self + 'a> {
+                $hash_to_curve($curve_id, domain_prefix)
             }
 
             fn is_on_curve(&self) -> Choice {

src/grumpkin/curve.rs

@@ -4,6 +4,7 @@ use crate::group::Curve;
 use crate::group::{prime::PrimeCurveAffine, Group, GroupEncoding};
 use crate::grumpkin::Fq;
 use crate::grumpkin::Fr;
+use crate::hash_to_curve::svdw_hash_to_curve;
 use crate::{
     batch_add, impl_add_binop_specify_output, impl_binops_additive,
     impl_binops_additive_specify_output, impl_binops_multiplicative,
@@ -31,6 +32,7 @@ new_curve_impl!(
     G1_A,
     G1_B,
     "grumpkin_g1",
+    |curve_id, domain_prefix| svdw_hash_to_curve(curve_id, domain_prefix, G1::SVDW_Z),
 );
 
 impl CurveAffineExt for G1Affine {
@@ -74,12 +76,21 @@ impl group::cofactor::CofactorGroup for G1 {
     }
 }
 
+impl G1 {
+    const SVDW_Z: Fq = Fq::ONE;
+}
+
 #[cfg(test)]
 mod tests {
     use crate::grumpkin::{Fr, G1};
     use crate::CurveExt;
     use ff::WithSmallOrderMulGroup;
 
+    #[test]
+    fn test_hash_to_curve() {
+        crate::tests::curve::hash_to_curve_test::<G1>();
+    }
+
     #[test]
     fn test_curve() {
         crate::tests::curve::curve_tests::<G1>();