Hyrax parallel commit

poly-commit/Cargo.toml

@@ -17,7 +17,7 @@ ark-crypto-primitives = {version = "^0.4.0", default-features = false, features
 ark-std = { version = "^0.4.0", default-features = false }
 blake2 = { version = "0.10", default-features = false }
 merlin = { version = "3.0.0", default-features = false }
-
+rand = { version = "0.8.0", optional = true }
 ark-relations = { version = "^0.4.0", default-features = false, optional = true }
 ark-r1cs-std = { version = "^0.4.0", default-features = false, optional = true }
 
@@ -55,4 +55,4 @@ default = [ "std", "parallel" ]
 std = [ "ark-ff/std", "ark-ec/std", "ark-poly/std", "ark-std/std", "ark-relations/std", "ark-serialize/std", "ark-crypto-primitives/std"]
 r1cs = [ "ark-relations", "ark-r1cs-std", "hashbrown", "ark-crypto-primitives/r1cs"]
 print-trace = [ "ark-std/print-trace" ]
-parallel = [ "std", "ark-ff/parallel", "ark-ec/parallel", "ark-poly/parallel", "ark-std/parallel", "rayon" ]
+parallel = [ "std", "ark-ff/parallel", "ark-ec/parallel", "ark-poly/parallel", "ark-std/parallel", "rayon", "rand" ]

poly-commit/src/hyrax/mod.rs

@@ -231,6 +231,7 @@ impl<G: AffineRepr, P: MultilinearExtension<G::ScalarField>>
     ///
     /// Panics if `rng` is None, since Hyrax requires randomness in order to
     /// commit to a polynomial
+    #[allow(unused_variables)]
     fn commit<'a>(
         ck: &Self::CommitterKey,
         polynomials: impl IntoIterator<Item = &'a LabeledPolynomial<G::ScalarField, P>>,
@@ -248,11 +249,10 @@ impl<G: AffineRepr, P: MultilinearExtension<G::ScalarField>>
         let mut coms = Vec::new();
         let mut rands = Vec::new();
 
+        #[cfg(not(feature = "parallel"))]
         let rng_inner = rng.expect("Committing to polynomials requires a random generator");
 
         for l_poly in polynomials {
-            let mut com_rands = Vec::new();
-
             let label = l_poly.label();
             let poly = l_poly.polynomial();
 
@@ -272,15 +272,16 @@ impl<G: AffineRepr, P: MultilinearExtension<G::ScalarField>>
             let m = flat_to_matrix_column_major(&poly.to_evaluations(), dim, dim);
 
             // Commiting to the matrix with one multi-commitment per row
-            let row_coms = m
-                .iter()
+            let (row_coms, com_rands): (Vec<_>, Vec<_>) = cfg_iter!(m)
                 .map(|row| {
+                    #[cfg(not(feature = "parallel"))]
                     let (c, r) = Self::pedersen_commit(ck, row, None, Some(rng_inner));
-                    // Storing the randomness used in the commitment
-                    com_rands.push(r);
-                    c
+                    #[cfg(feature = "parallel")]
+                    let (c, r) =
+                        Self::pedersen_commit(ck, row, None, Some(&mut rand::thread_rng()));
+                    (c, r)
                 })
-                .collect();
+                .unzip();
 
             let com = HyraxCommitment { row_coms };
             let l_comm = LabeledCommitment::new(label.to_string(), com, Some(1));