feat: Support ed25519 batch signature verification

Cargo.toml

@@ -24,7 +24,6 @@ branch = "otak/fix-1.0.3"
 [features]
 default = []
 cryptobox-identity = []
-unclamped-dh-exchange = []
 hazmat = []
 
 [dependencies]
@@ -42,7 +41,7 @@ sha2 = "0.10"
 hkdf = "0.12"
 hmac = "0.12"
 chacha20 = "0.9"
-ed25519-dalek = { version = "2.0.0-pre.0", features = ["zeroize"] }
+ed25519-dalek = { version = "2.0.0-pre.0", features = ["zeroize", "batch"] }
 x25519-dalek = { git = "https://github.com/dalek-cryptography/x25519-dalek.git", branch = "release/2.0" }
 curve25519-dalek = { version = "4.0.0-rc.1", features = ["precomputed-tables"] }
 subtle = "2.4"

benches/benchmarks.rs

@@ -88,13 +88,10 @@ fn bench_verify_batched(c: &mut Criterion) {
         &inputs,
         |b, inputs| {
             b.iter(|| {
-                for (sig, msg) in inputs {
-                    let _r = x.public_key.verify(&sig, &msg);
-                }
+                let _r = x.public_key.verify_batch(inputs);
             })
         },
     );
-
     group.finish();
 }
 

src/internal/keys.rs

@@ -595,6 +595,18 @@ impl PublicKey {
         res.is_ok()
     }
 
+    #[must_use]
+    pub fn verify_batch(
+        &self,
+        verifying_contents: &std::collections::HashMap<Signature, Vec<u8>>,
+    ) -> bool {
+        let messages: Vec<&[u8]> = verifying_contents.values().map(|m| m.as_slice()).collect();
+        let signatures: Vec<_> = verifying_contents.keys().map(|s| s.0).collect();
+        let verifying_keys: Vec<_> = (0..signatures.len()).map(|_| self.0.clone()).collect();
+
+        ed25519_dalek::verify_batch(&messages, &signatures, &verifying_keys).is_ok()
+    }
+
     pub fn as_slice(&self) -> &[u8] {
         self.0.as_bytes()
     }
@@ -665,10 +677,16 @@ pub fn rand_bytes(size: usize) -> Vec<u8> {
 // Signature ////////////////////////////////////////////////////////////////
 
 // SAFETY: ZeroizeOnDrop isn't needed as ed25519_dalek types already implement Zeroize + Drop
-#[derive(Clone, Debug, Hash, Eq, PartialEq)]
+#[derive(Clone, Debug, Eq, PartialEq)]
 #[repr(transparent)]
 pub struct Signature(ed25519_dalek::Signature);
 
+impl std::hash::Hash for Signature {
+    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+        state.write(&self.0.to_bytes());
+    }
+}
+
 impl Signature {
     pub fn encode<W: Write>(&self, e: &mut Encoder<W>) -> EncodeResult<()> {
         e.object(1)?;