Merge pull request #39 from Yoii-Inc/feat/fix_constraints_equality_zero

Feat/fix constraints equality zero

mpc-algebra/src/r1cs_helper/mpc_fp.rs

@@ -460,18 +460,14 @@ impl<F: PrimeField, S: FieldShare<F>> MpcAllocatedFp<F, S> {
 
 impl<F: PrimeField + SquareRootField, S: FieldShare<F>> MpcAllocatedFp<F, S> {
     pub fn is_zero(&self) -> Result<MpcBoolean<F, S>, SynthesisError> {
-        let is_not_zero = MpcBoolean::new_witness(self.cs.clone(), || {
-            Ok(MpcField::one() - self.value.get()?.is_zero_shared())
-        })?;
+        let is_zero_value = self.value.get()?.is_zero_shared();
 
-        let multiplier = self.cs.new_witness_variable(|| {
-            // reveal is not recommended. It is better to avoid revealing.
-            if is_not_zero.value_field()?.reveal().is_one() {
-                (self.value.get()?).inverse().get()
-            } else {
-                Ok(MpcField::one())
-            }
-        })?;
+        let is_not_zero =
+            MpcBoolean::new_witness(self.cs.clone(), || Ok(MpcField::one() - is_zero_value))?;
+
+        let multiplier = self
+            .cs
+            .new_witness_variable(|| (self.value.get()? + is_zero_value).inverse().get())?;
 
         self.cs
             .enforce_constraint(lc!() + self.variable, lc!() + multiplier, is_not_zero.lc())?;

mpc-algebra/src/wire/field.rs

@@ -650,6 +650,7 @@ impl<F: PrimeField + SquareRootField, S: FieldShare<F>> BitDecomposition for Mpc
     fn bit_decomposition(&self) -> Self::Output {
         match self.is_shared() {
             true => {
+                let timer = start_timer!(|| "Bit Decomposition");
                 let rng = &mut ark_std::test_rng();
 
                 let l = F::Params::MODULUS_BITS as usize;
@@ -714,6 +715,7 @@ impl<F: PrimeField + SquareRootField, S: FieldShare<F>> BitDecomposition for Mpc
 
                 // 6
                 assert!(h.len() == l + 1);
+                end_timer!(timer);
                 h[..l].to_vec() // remove the last element
             }
             false => {

src/bin_test_marlin.rs

@@ -21,5 +21,7 @@ fn main() {
     let opt = Opt::from_args();
     Net::init_from_file(opt.input.to_str().unwrap(), opt.id);
     marlin::mpc_test_prove_and_verify(1);
-    // marlin::mpc_test_prove_and_verify_pedersen(1);
+    marlin::mpc_test_prove_and_verify_pedersen(1);
+    marlin::test_equality_zero(1);
+    marlin::test_bit_decomposition(1);
 }

src/circuits.rs

@@ -5,6 +5,5 @@ pub use pedersen::*;
 pub mod werewolf;
 pub use werewolf::*;
 pub mod equality_zero;
-pub use equality_zero::*;
+
 pub mod bit_decomposition;
-pub use bit_decomposition::*;

src/circuits/bit_decomposition.rs

@@ -1,15 +1,7 @@
 use ark_ff::PrimeField;
-use ark_r1cs_std::{
-    alloc::AllocVar,
-    boolean::Boolean,
-    eq::EqGadget,
-    fields::{fp::FpVar, FieldVar},
-    ToBitsGadget,
-};
+use ark_r1cs_std::{alloc::AllocVar, fields::fp::FpVar, ToBitsGadget};
 use ark_relations::r1cs::{ConstraintSynthesizer, ConstraintSystemRef, SynthesisError};
-use mpc_algebra::{
-    malicious_majority::MpcField, MpcBoolean, MpcEqGadget, MpcFpVar, MpcToBitsGadget,
-};
+use mpc_algebra::{malicious_majority::MpcField, MpcFpVar, MpcToBitsGadget};
 
 type Fr = ark_bls12_377::Fr;
 type MFr = MpcField<Fr>;
@@ -22,7 +14,7 @@ impl ConstraintSynthesizer<MFr> for BitDecompositionCircuit<MFr> {
     fn generate_constraints(self, cs: ConstraintSystemRef<MFr>) -> Result<(), SynthesisError> {
         let a_var = MpcFpVar::new_witness(cs.clone(), || Ok(self.a))?;
 
-        let bits = a_var.to_bits_le()?;
+        let _bits = a_var.to_bits_le()?;
 
         Ok(())
     }
@@ -32,7 +24,7 @@ impl ConstraintSynthesizer<Fr> for BitDecompositionCircuit<Fr> {
     fn generate_constraints(self, cs: ConstraintSystemRef<Fr>) -> Result<(), SynthesisError> {
         let a_var = FpVar::new_witness(cs.clone(), || Ok(self.a))?;
 
-        let bits = a_var.to_bits_le()?;
+        let _bits = a_var.to_bits_le()?;
 
         Ok(())
     }