add initial nova circuits structure, NIFS circuit partially implemented

src/lib.rs

@@ -4,6 +4,7 @@
 #![allow(unused)] // TMP
 
 mod nifs;
+mod novacircuit;
 mod pedersen;
 mod r1cs;
 mod transcript;

src/novacircuit.rs

@@ -0,0 +1,87 @@
+use ark_crypto_primitives::snark::{FromFieldElementsGadget, SNARKGadget, SNARK};
+use ark_ec::CurveGroup;
+use ark_ff::{fields::Fp256, Field, PrimeField};
+use ark_r1cs_std::{
+    alloc::{AllocVar, AllocationMode},
+    bits::uint8::UInt8,
+    boolean::Boolean,
+    eq::EqGadget,
+    fields::{fp::FpVar, FieldVar},
+    groups::GroupOpsBounds,
+    prelude::CurveVar,
+    ToBitsGadget,
+};
+use ark_relations::r1cs::{ConstraintSynthesizer, ConstraintSystemRef, Namespace, SynthesisError};
+use ark_std::ops::Mul;
+
+use core::{borrow::Borrow, marker::PhantomData};
+use derivative::Derivative;
+
+// pub trait Nova<F: PrimeField> {}
+
+pub trait Config<Fq: PrimeField, Fr: PrimeField> {
+    type AugmentedFunctionCircuit: SNARK<Fq>; // F'
+    type FunctionCircuit: ConstraintSynthesizer<Fq>; // F
+    type DummyStepCircuit: SNARK<Fr>;
+}
+
+pub struct AugmentedFCircuit<
+    Fq: PrimeField,
+    Fr: PrimeField,
+    C: CurveGroup,
+    GC: CurveVar<C, Fq>,
+    Cfg: Config<Fq, Fr>,
+> {
+    pub dummystep_vk: Option<<Cfg::DummyStepCircuit as SNARK<Fr>>::VerifyingKey>,
+    _c: PhantomData<C>,
+    _gc: PhantomData<GC>,
+}
+
+impl<Fq: PrimeField, Fr: PrimeField, C: CurveGroup, GC: CurveVar<C, Fq>, Cfg: Config<Fq, Fr>>
+    ConstraintSynthesizer<Fq> for AugmentedFCircuit<Fq, Fr, C, GC, Cfg>
+{
+    fn generate_constraints(self, cs: ConstraintSystemRef<Fq>) -> Result<(), SynthesisError> {
+        unimplemented!();
+        // nifscircuit::NIFSGadget::<Fq, C, GC<Fq, C>>::verify();
+        // hash
+    }
+}
+
+pub struct NIFSGadget<F: PrimeField, C: CurveGroup, GC: CurveVar<C, F>> {
+    _f: PhantomData<F>,
+    _c: PhantomData<C>,
+    _gc: PhantomData<GC>,
+}
+
+impl<F: PrimeField, C: CurveGroup, GC: CurveVar<C, F>> NIFSGadget<F, C, GC> {
+    // implements the constraints for NIFS.V
+    pub fn verify(
+        r: FpVar<F>,
+        cmT: GC,
+        // phi1, phi2 and phi3
+        cmE1: GC,
+        cmE2: GC,
+        cmE3: GC,
+        u1: FpVar<F>,
+        u2: FpVar<F>,
+        u3: FpVar<F>,
+        cmW1: GC,
+        cmW2: GC,
+        cmW3: GC,
+        // x's size will depend on the num_publicinputs of F circuit
+        x1: Vec<FpVar<F>>,
+        x2: Vec<FpVar<F>>,
+        x3: Vec<FpVar<F>>,
+    ) -> Result<Boolean<F>, SynthesisError> {
+        let r2 = r.square()?;
+        cmE3.is_eq(
+            &(cmE1
+                + cmT.scalar_mul_le(r.to_bits_le()?.iter())?
+                + cmE2.scalar_mul_le(r2.to_bits_le()?.iter())?),
+        )?;
+        u3.is_eq(&(u1 + r.clone() * u2))?;
+        cmW3.is_eq(&(cmW1 + cmW2.scalar_mul_le(r.to_bits_le()?.iter())?))
+
+        // TODO x's check
+    }
+}