Implement Nova's NIFS.P & NIFS.V (#7)

src/folding/mod.rs

@@ -0,0 +1 @@
+pub mod nova;

src/folding/nova/mod.rs

@@ -0,0 +1,62 @@
+use ark_crypto_primitives::sponge::Absorb;
+use ark_ec::{CurveGroup, Group};
+use ark_std::fmt::Debug;
+use ark_std::{One, Zero};
+
+use crate::pedersen::{Params as PedersenParams, Pedersen};
+
+pub mod nifs;
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct CommittedInstance<C: CurveGroup> {
+    pub cmE: C,
+    pub u: C::ScalarField,
+    pub cmW: C,
+    pub x: Vec<C::ScalarField>,
+}
+impl<C: CurveGroup> CommittedInstance<C> {
+    pub fn empty() -> Self {
+        CommittedInstance {
+            cmE: C::zero(),
+            u: C::ScalarField::one(),
+            cmW: C::zero(),
+            x: Vec::new(),
+        }
+    }
+}
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct Witness<C: CurveGroup> {
+    pub E: Vec<C::ScalarField>,
+    pub rE: C::ScalarField,
+    pub W: Vec<C::ScalarField>,
+    pub rW: C::ScalarField,
+}
+
+impl<C: CurveGroup> Witness<C>
+where
+    <C as Group>::ScalarField: Absorb,
+{
+    pub fn new(w: Vec<C::ScalarField>, e_len: usize) -> Self {
+        Self {
+            E: vec![C::ScalarField::zero(); e_len],
+            rE: C::ScalarField::one(),
+            W: w,
+            rW: C::ScalarField::one(),
+        }
+    }
+    pub fn commit(
+        &self,
+        params: &PedersenParams<C>,
+        x: Vec<C::ScalarField>,
+    ) -> CommittedInstance<C> {
+        let cmE = Pedersen::commit(params, &self.E, &self.rE);
+        let cmW = Pedersen::commit(params, &self.W, &self.rW);
+        CommittedInstance {
+            cmE,
+            u: C::ScalarField::one(),
+            cmW,
+            x,
+        }
+    }
+}