DefaultCommitter now uses Windowed version for first five elements

banderwagon/src/msm_windowed_sign.rs

@@ -5,6 +5,7 @@ use ark_ff::Zero;
 use ark_ff::{BigInteger, BigInteger256};
 use std::ops::Neg;
 
+#[derive(Debug, Clone)]
 pub struct MSMPrecompWindowSigned {
     tables: Vec<Vec<EdwardsAffine>>,
     num_windows: usize,

ipa-multipoint/src/committer.rs

@@ -1,4 +1,4 @@
-use banderwagon::{msm::MSMPrecompWnaf, Element, Fr};
+use banderwagon::{msm::MSMPrecompWnaf, msm_windowed_sign::MSMPrecompWindowSigned, Element, Fr};
 
 // This is the functionality that commits to the branch nodes and computes the delta optimization
 // For consistency with the Pcs, ensure that this component uses the same CRS as the Pcs
@@ -24,19 +24,32 @@ pub trait Committer {
 
 #[derive(Clone, Debug)]
 pub struct DefaultCommitter {
+    precomp_first_five: MSMPrecompWindowSigned,
     precomp: MSMPrecompWnaf,
 }
 
 impl DefaultCommitter {
     pub fn new(points: &[Element]) -> Self {
-        let precomp = MSMPrecompWnaf::new(points, 12);
+        // Take the first five elements and use a more aggressive optimization strategy
+        // since they are used for computing storage keys.
 
-        Self { precomp }
+        let (points_five, rest) = points.split_at(5);
+
+        let precomp_first_five = MSMPrecompWindowSigned::new(points_five, 16);
+        let precomp = MSMPrecompWnaf::new(rest, 12);
+
+        Self {
+            precomp,
+            precomp_first_five,
+        }
     }
 }
 
 impl Committer for DefaultCommitter {
     fn commit_lagrange(&self, evaluations: &[Fr]) -> Element {
+        if evaluations.len() <= 5 {
+            return self.precomp_first_five.mul(&evaluations);
+        }
         // Preliminary benchmarks indicate that the parallel version is faster
         // for vectors of length 64 or more
         if evaluations.len() >= 64 {