muhash: Improve benchmarks, and add inverse check in debug mode

kaspanet · Dec 23, 2022 · 6e64a9d · 6e64a9d
1 parent 04d52ff
commit 6e64a9d
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Showing 2 changed files with 16 additions and 11 deletions.
diff --git a/crypto/muhash/benches/bench.rs b/crypto/muhash/benches/bench.rs
@@ -8,12 +8,16 @@ use muhash::MuHash;
 
 fn bench_muhash(c: &mut Criterion) {
     let mut rng = ChaCha8Rng::from_seed([42u8; 32]);
+    let mut rand_set = MuHash::new();
 
     let mut data = [0u8; 100];
+    // Set the numerator and denominators.
+    rng.fill_bytes(&mut data);
+    rand_set.add_element(&data);
+    rng.fill_bytes(&mut data);
+    rand_set.remove_element(&data);
+
     rng.fill_bytes(&mut data);
-    let mut rand_set_serialized = [0u8; 384];
-    rng.fill_bytes(&mut rand_set_serialized);
-    let mut rand_set = MuHash::deserialize(rand_set_serialized).unwrap();
 
     c.bench_function("MuHash::add_element", |b| {
         let mut muhash = MuHash::new();
@@ -62,14 +66,10 @@ fn bench_muhash(c: &mut Criterion) {
         b.iter(|| black_box(muhash.clone()).serialize())
     });
 
-    c.bench_function("MuHash::serialize rand", |b| {
-        let muhash = MuHash::deserialize(rand_set_serialized).unwrap();
-        b.iter(|| black_box(muhash.clone()).serialize())
-    });
+    c.bench_function("MuHash::serialize rand", |b| b.iter(|| black_box(rand_set.clone()).serialize()));
 
     c.bench_function("MuHash::finalize", |b| {
-        let muhash = MuHash::deserialize(rand_set_serialized).unwrap();
-        b.iter(|| black_box(muhash.clone()).finalize());
+        b.iter(|| black_box(rand_set.clone()).finalize());
     });
 }
 

diff --git a/crypto/muhash/src/u3072.rs b/crypto/muhash/src/u3072.rs
@@ -147,8 +147,13 @@ impl U3072 {
             a.full_reduce();
         }
         // The only value that doesn't have a multiplicative inverse is 0, and 0/x is 0.
-        let inv = Uint3072(a.limbs).mod_inverse(Self::UINT_PRIME).unwrap_or_default();
-        Self { limbs: inv.0 }
+        let inv = Self { limbs: Uint3072(a.limbs).mod_inverse(Self::UINT_PRIME).unwrap_or_default().0 };
+        if cfg!(debug_assertions) {
+            let mut one = inv;
+            one *= a;
+            assert_eq!(one, Self::one());
+        }
+        inv
     }
 
     fn div(&mut self, other: &Self) {