feat: add grumpkin::fp (bn254::fr)

crates/curves/src/weierstrass/grumpkin.rs

@@ -0,0 +1,116 @@
+use generic_array::GenericArray;
+use num::{BigUint, Num, Zero};
+use serde::{Deserialize, Serialize};
+use typenum::{U32, U62};
+
+use super::{FieldType, FpOpField, SwCurve, WeierstrassParameters};
+use crate::{
+    params::{FieldParameters, NumLimbs},
+    CurveType, EllipticCurveParameters,
+};
+
+#[derive(Debug, Clone, Copy, PartialEq, Serialize, Deserialize)]
+/// Grumpkin curve parameter
+pub struct GrumpkinParameters;
+
+pub type Grumpkin = SwCurve<GrumpkinParameters>;
+
+#[derive(Debug, Default, Clone, Copy, PartialEq, Serialize, Deserialize)]
+/// Grumpkin base field parameter
+pub struct GrumpkinBaseField;
+
+impl FieldParameters for GrumpkinBaseField {
+    // python:
+    //   fp = 21888242871839275222246405745257275088548364400416034343698204186575808495617
+    //   list(int.to_bytes(fp, length=32, byteorder='little'))
+    const MODULUS: &'static [u8] = &[
+        1, 0, 0, 240, 147, 245, 225, 67, 145, 112, 185, 121, 72, 232, 51, 40, 93, 88, 129, 129,
+        182, 69, 80, 184, 41, 160, 49, 225, 114, 78, 100, 48,
+    ];
+
+    // A rough witness-offset estimate given the size of the limbs and the size of the field.
+    const WITNESS_OFFSET: usize = 1usize << 14;
+
+    // Grumpkin::Fp is Bn254::Fr
+    fn modulus() -> BigUint {
+        BigUint::from_str_radix(
+            "21888242871839275222246405745257275088548364400416034343698204186575808495617",
+            10,
+        )
+        .unwrap()
+    }
+}
+
+impl FpOpField for GrumpkinBaseField {
+    const FIELD_TYPE: FieldType = FieldType::Grumpkin;
+}
+
+impl NumLimbs for GrumpkinBaseField {
+    type Limbs = U32;
+    type Witness = U62;
+}
+
+impl EllipticCurveParameters for GrumpkinParameters {
+    type BaseField = GrumpkinBaseField;
+
+    const CURVE_TYPE: CurveType = CurveType::Grumpkin;
+}
+
+// https://github.com/lambdaclass/lambdaworks/blob/main/math/src/elliptic_curve/short_weierstrass/curves/grumpkin/curve.rs
+impl WeierstrassParameters for GrumpkinParameters {
+    const A: GenericArray<u8, U32> = GenericArray::from_array([
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0,
+    ]);
+
+    // -17
+    // b = fp - 17
+    // list(int.to_bytes(b, length=32, byteorder='little'))
+    const B: GenericArray<u8, U32> = GenericArray::from_array([
+        240, 255, 255, 239, 147, 245, 225, 67, 145, 112, 185, 121, 72, 232, 51, 40, 93, 88, 129,
+        129, 182, 69, 80, 184, 41, 160, 49, 225, 114, 78, 100, 48,
+    ]);
+
+    fn generator() -> (BigUint, BigUint) {
+        let x = BigUint::from(1u32);
+        // sqrt(-16)
+        let y = BigUint::from_str_radix(
+            "17631683881184975370165255887551781615748388533673675138860",
+            10,
+        )
+        .unwrap();
+        (x, y)
+    }
+
+    fn prime_group_order() -> num::BigUint {
+        BigUint::from_str_radix(
+            "21888242871839275222246405745257275088696311157297823662689037894645226208583",
+            10,
+        )
+        .unwrap()
+    }
+
+    fn a_int() -> BigUint {
+        BigUint::zero()
+    }
+
+    fn b_int() -> BigUint {
+        BigUint::from_str_radix(
+            "21888242871839275222246405745257275088548364400416034343698204186575808495600",
+            10,
+        )
+        .unwrap()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+
+    use super::*;
+    use crate::utils::biguint_from_limbs;
+
+    #[test]
+    fn test_weierstrass_biguint_scalar_mul() {
+        assert_eq!(biguint_from_limbs(GrumpkinBaseField::MODULUS), GrumpkinBaseField::modulus());
+    }
+}