fix compilation issues

crypto/kzg/Cargo.toml

@@ -19,6 +19,7 @@ hex = "0.4.2"
 eth2_hashing = "0.3.0"
 ethereum-types = "0.12.1"
 c-kzg = {git = "https://github.com/pawanjay176/c-kzg-4844", rev = "c9e4fa0dabdd000738b7fcdf85a72880a5da8748" }
+arbitrary = { version = "1.0", features = ["derive"], optional = true }
 
 [features]
 default = ["mainnet-spec"]

crypto/kzg/src/kzg_commitment.rs

@@ -102,3 +102,12 @@ impl Debug for KzgCommitment {
         write!(f, "{}", eth2_serde_utils::hex::encode(&self.0))
     }
 }
+
+#[cfg(feature = "arbitrary")]
+impl arbitrary::Arbitrary<'_> for KzgCommitment {
+    fn arbitrary(u: &mut arbitrary::Unstructured<'_>) -> arbitrary::Result<Self> {
+        let mut bytes = [0u8; KZG_COMMITMENT_BYTES_LEN];
+        u.fill_buffer(&mut bytes)?;
+        Ok(KzgCommitment(bytes))
+    }
+}

crypto/kzg/src/kzg_proof.rs

@@ -126,3 +126,12 @@ impl Debug for KzgProof {
         write!(f, "{}", eth2_serde_utils::hex::encode(&self.0))
     }
 }
+
+#[cfg(feature = "arbitrary")]
+impl arbitrary::Arbitrary<'_> for KzgProof {
+    fn arbitrary(u: &mut arbitrary::Unstructured<'_>) -> arbitrary::Result<Self> {
+        let mut bytes = [0u8; KZG_PROOF_BYTES_LEN];
+        u.fill_buffer(&mut bytes)?;
+        Ok(KzgProof(bytes))
+    }
+}