Add curve support for Grumpkin

packages/ecdh/Nargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "ecdh"
 type = "lib"
-authors = ["YashBit", "signorecello"]
+authors = ["YashBit", "signorecello","karl"]
 
 [dependencies]
 ec = { tag = "v0.1.2", git = "https://github.com/noir-lang/ec" }

packages/ecdh/src/gpk.nr

@@ -0,0 +1,40 @@
+use crate::ECDHSWTrait;
+use ec::swcurve::affine::{Curve, Point};
+
+pub struct Grumpkin {
+    pub private_key: Field,
+    pub curve: Curve,
+}
+
+impl ECDHSWTrait for Grumpkin {
+    fn new(private_key: Field) -> Self {
+        let curve = create_grumpkin_curve();
+        Self { curve, private_key }
+    }
+
+    fn derive_public_key(self) -> Point {
+        // Use the stored curve instance
+        self.curve.mul(self.private_key, self.curve.gen)
+    }
+
+    fn derive_shared_key(self, public_key: Point) -> Field {
+        // Use the stored curve instance
+        let shared_point = self.curve.mul(self.private_key,public_key);
+
+        // Return x-coordinate as the shared secret
+        shared_point.x
+    }
+}
+
+
+fn create_grumpkin_curve() -> Curve {
+    // Let Noir handle the field arithmetic
+    let a = 0;
+    let b = -17; 
+
+    let gen_x = 1;
+    let gen_y = 0x2cf135e7506a45d632d270d45f1181294833fc48d823f272c;
+
+    let generator = Point::new(gen_x, gen_y);
+    Curve::new(a, b, generator)
+}

packages/ecdh/src/lib.nr

@@ -1,8 +1,17 @@
 mod bjj;
-use ec::tecurve::affine::Point;
+use ec::tecurve::affine::Point ;
+
+mod gpk;
+use ec::swcurve::affine::Point as SWPoint;
 
 pub trait ECDHTrait {
     fn new(private_key: Field) -> Self;
     fn derive_public_key(self) -> Point;
     fn derive_shared_key(self, public_key: Point) -> Field;
 }
+
+pub trait ECDHSWTrait {
+    fn new(private_key: Field) -> Self;
+    fn derive_public_key(self) -> SWPoint;
+    fn derive_shared_key(self, public_key: SWPoint) -> Field;
+}

tests/Nargo.toml

@@ -4,6 +4,8 @@ type = "lib"
 authors = ["signorecello"]
 
 [dependencies]
-bignum = { git = "https://github.com/noir-lang/noir-bignum", tag = "v0.6.0" }
+bignum = { git = "https://github.com/noir-lang/noir-bignum", tag = "v0.6.1" }
 trees = { path = "../packages/merkle-trees" }
 ecdh = { path = "../packages/ecdh" }
+ec = { tag = "v0.1.2", git = "https://github.com/noir-lang/ec" }
+

tests/src/ecdh/mod.nr

@@ -1,8 +1,13 @@
 use ecdh::{bjj::BJJ, ECDHTrait, Point};
+use ecdh::{gpk::Grumpkin, ECDHSWTrait};
+use ec::swcurve::affine::Point as swPoint;
 
 global alice_sk: Field = 0x60c0102756aac2cf5d7277792a469bff83dfe3d3e7e50ad5a55383f3a89283e;
 global bob_sk: Field = 0x86cdaad8886954a2eb20142fb98468d476a2d6c7b2c571af42cdc041b1a923c;
 
+global grumpkin_alice_sk: Field = 0x12a4d37d71d32255c4e9b3d5f6c8c1b0e9a4c7d1b3e5f6c8a2d4e7f1b2c3d5e;
+global grumpkin_bob_sk: Field = 0x2c8d3e7a1f5b9d2e6c4a8b1d3f5e7c9a2d4b6e8f1a3c5d7e9b2d4f6a8c3e1;
+
 #[test]
 fn test_pk() {
     let ecdh = BJJ::new(alice_sk);
@@ -13,6 +18,20 @@ fn test_pk() {
     let pk = ecdh.derive_public_key();
     assert(pk == expected_pk);
 }
+#[test]
+fn test_grumpkin_pk() {
+    let ecdh = Grumpkin::new(grumpkin_alice_sk);
+
+    let expected_pk = swPoint::new(
+        0x159cf346346bebd155d7fc84f67bfb29cd9d26a920c4652823b1fc7b327490ca,
+        0x2869bca8dd2c9d498c9ca4463c91f5f3e32cb40af3cfe3a7c5e8357436642b33,
+    );
+
+    let pk = ecdh.derive_public_key();
+
+    assert(pk.x == expected_pk.x);
+    assert(pk.y == expected_pk.y);
+}
 
 #[test]
 fn test_shared_k() {
@@ -27,3 +46,22 @@ fn test_shared_k() {
 
     assert(shared_key_with_bob == shared_key_with_alice);
 }
+
+#[test]
+fn test_grumpkin_shared_k() {
+    // Create ECDH instances for Alice and Bob
+    let alice_ecdh = Grumpkin::new(grumpkin_alice_sk);
+    let bob_ecdh = Grumpkin::new(grumpkin_bob_sk);
+
+    // Derive public keys
+    let alice_pk: swPoint = alice_ecdh.derive_public_key();
+    let bob_pk: swPoint = bob_ecdh.derive_public_key();
+
+    // Compute shared keys
+    let shared_key_with_bob = alice_ecdh.derive_shared_key(bob_pk);
+    let shared_key_with_alice = bob_ecdh.derive_shared_key(alice_pk);
+
+    // Assert equality
+    assert_eq(shared_key_with_bob, shared_key_with_alice);
+}
+