WIP

noir-projects/aztec-nr/aztec/src/keys/point_to_symmetric_key.nr

@@ -1,15 +1,16 @@
-use dep::protocol_types::{grumpkin_point::GrumpkinPoint, grumpkin_private_key::GrumpkinPrivateKey};
-use dep::std::hash::sha256;
+use dep::protocol_types::grumpkin_point::GrumpkinPoint;
+use dep::std::{hash::sha256, grumpkin_scalar::GrumpkinScalar, grumpkin_scalar_mul::grumpkin_variable_base};
 
-pub fn point_to_symmetric_key(secret: GrumpkinPrivateKey, point: GrumpkinPoint) -> [u8; 32] {
-    // let shared_secret = secret * point; // TODO(benesjan): implement grumpkin_scalar_mul::grumpkin_variable_base
-    let shared_secret = point;
+pub fn point_to_symmetric_key(secret: GrumpkinScalar, point: GrumpkinPoint) -> [u8; 32] {
+    let shared_secret_fields = grumpkin_variable_base(point.x, point.y, secret);
+    // TODO(https://github.com/AztecProtocol/aztec-packages/issues/6061): make the func return Point struct directly
+    let shared_secret = GrumpkinPoint::new(shared_secret_fields[0], shared_secret_fields[1]);
     sha256(shared_secret.to_be_bytes())
 }
 
 #[test]
 fn check_point_to_symmetric_key() {
-    let secret = GrumpkinPrivateKey::new(5, 6);
+    let secret = GrumpkinScalar::new(5, 6);
     let point = GrumpkinPoint::new(7, 8);
 
     let key = point_to_symmetric_key(secret, point);