add faster signature verification

src/helpers/g1point.ts

@@ -5,7 +5,7 @@ import assert from "assert";
 import {calculateYFlag, getModulus} from "./utils";
 import * as random from "secure-random";
 import {FP_POINT_LENGTH} from "../constants";
-import {bytes48} from "@chainsafe/eth2.0-types";
+import {BLSPubkey, bytes48} from "@chainsafe/eth2.0-types";
 
 export class G1point {
 
@@ -28,6 +28,10 @@ export class G1point {
     return new G1point(sum);
   }
 
+  public addRaW(other: bytes48): G1point {
+    return this.add(G1point.fromBytesCompressed(other));
+  }
+
   public equal(other: G1point): boolean {
     return this.point.equals(other.point);
   }
@@ -102,6 +106,14 @@ export class G1point {
     return new G1point(point);
   }
 
+  public static aggregate(values: bytes48[]): G1point {
+    return values.map((value) => {
+      return G1point.fromBytesCompressed(value);
+    }).reduce((previousValue, currentValue): G1point => {
+      return previousValue.add(currentValue);
+    });
+  }
+
   public static generator(): G1point {
     return new G1point(ctx.ECP.generator());
   }

src/index.ts

@@ -58,11 +58,7 @@ export function aggregatePubkeys(publicKeys: BLSPubkey[]): BLSPubkey {
   if(publicKeys.length === 0) {
     return new G1point(new ctx.ECP()).toBytesCompressed();
   }
-  return publicKeys.map((publicKey): G1point => {
-    return G1point.fromBytesCompressed(publicKey);
-  }).reduce((previousValue, currentValue): G1point => {
-    return previousValue.add(currentValue);
-  }).toBytesCompressed();
+  return G1point.aggregate(publicKeys).toBytesCompressed();
 }
 
 /**
@@ -77,6 +73,8 @@ export function verify(publicKey: BLSPubkey, messageHash: bytes32, signature: BL
     const key = PublicKey.fromBytes(publicKey);
     const sig = Signature.fromCompressedBytes(signature);
 
+    key.getPoint().getPoint().affine();
+    sig.getPoint().getPoint().affine();
     const g1Generated = G1point.generator();
     const e1 = ElipticCurvePairing.pair(key.getPoint(), G2point.hashToG2(messageHash, domain));
     const e2 = ElipticCurvePairing.pair(g1Generated, sig.getPoint());
@@ -98,20 +96,50 @@ export function verifyMultiple(publicKeys: BLSPubkey[], messageHashes: bytes32[]
     return false;
   }
   try {
-    const g1Generated = G1point.generator();
+    const sig = Signature.fromCompressedBytes(signature).getPoint();
+    sig.getPoint().affine();
+
     const eCombined = new ctx.FP12(1);
-    publicKeys.forEach((publicKey, index): void => {
-      const g2 = G2point.hashToG2(messageHashes[index], domain);
+
+    const reduction = messageHashes.reduce((previous, current, index) => {
+      if(previous.hash && current.equals(previous.hash)) {
+        return {
+          hash: previous.hash,
+          publicKey: previous.publicKey ?
+            previous.publicKey.addRaW(publicKeys[index])
+            :
+            G1point.fromBytesCompressed(publicKeys[index]),
+        };
+      } else if(!!previous.hash) {
+        const g2 = G2point.hashToG2(previous.hash, domain);
         eCombined.mul(
           ElipticCurvePairing.pair(
-          PublicKey.fromBytes(publicKey).getPoint(),
+            previous.publicKey,
             g2
           )
         );
-    });
-    const e2 = ElipticCurvePairing.pair(g1Generated, Signature.fromCompressedBytes(signature).getPoint());
+        return {hash: current, publicKey: G1point.fromBytesCompressed(publicKeys[index])};
+      } else {
+        return {
+          hash: current,
+          publicKey: G1point.fromBytesCompressed(publicKeys[index])
+        };
+      }
+    }, {hash: null, publicKey: null});
+
+    const g2Final = G2point.hashToG2(reduction.hash, domain);
+    const keyFinal = reduction.publicKey;
+    eCombined.mul(
+      ElipticCurvePairing.pair(
+        keyFinal,
+        g2Final
+      )
+    );
+
+    const e2 = ElipticCurvePairing.pair(G1point.generator(), sig);
     return e2.equals(eCombined);
   } catch (e) {
+    console.log(e);
     return false;
   }
 }

test/spec/spec-tests

@@ -1 +1 @@
-Subproject commit 7567342c966c4e020f6ab3889f93cedb65ea9bfe
+Subproject commit 15a1d85125682d3ffc09a1ee9639f46c4a1653f6

test/unit/index.test.ts

@@ -65,7 +65,7 @@ describe('test bls', function () {
     it('should fail verify signature of different message', () => {
       const keypair = Keypair.generate();
       const messageHash = Buffer.from(sha256.arrayBuffer("Test message"));
-      const messageHash2 = Buffer.from(sha256.arrayBuffer("Test message2"))
+      const messageHash2 = Buffer.from(sha256.arrayBuffer("Test message2"));
       const domain = Buffer.from("01", 'hex');
       const signature = keypair.privateKey.sign(
         G2point.hashToG2(messageHash, domain)
@@ -117,7 +117,7 @@ describe('test bls', function () {
   describe('verify multiple', function() {
 
     it('should verify aggregated signatures', function () {
-      this.timeout(5000)
+      this.timeout(5000);
 
 
       const domain = Buffer.alloc(8, 0);
@@ -162,8 +162,48 @@ describe('test bls', function () {
       expect(result).to.be.true;
     });
 
+    it('should verify aggregated signatures - same message', function () {
+      this.timeout(5000);
+
+
+      const domain = Buffer.alloc(8, 0);
+
+      const keypair1 = Keypair.generate();
+      const keypair2 = Keypair.generate();
+      const keypair3 = Keypair.generate();
+      const keypair4 = Keypair.generate();
+
+      const message = Buffer.from("Test1", 'utf-8');
+
+      const signature1 = keypair1.privateKey.signMessage(message, domain);
+      const signature2 = keypair2.privateKey.signMessage(message, domain);
+      const signature3 = keypair3.privateKey.signMessage(message, domain);
+      const signature4 = keypair4.privateKey.signMessage(message, domain);
+
+      const aggregateSignature = bls.aggregateSignatures([
+        signature1.toBytesCompressed(),
+        signature2.toBytesCompressed(),
+        signature3.toBytesCompressed(),
+        signature4.toBytesCompressed(),
+      ]);
+
+      const result = bls.verifyMultiple(
+        [
+          keypair1.publicKey.toBytesCompressed(),
+          keypair2.publicKey.toBytesCompressed(),
+          keypair3.publicKey.toBytesCompressed(),
+          keypair4.publicKey.toBytesCompressed()
+        ],
+        [message, message, message, message],
+        aggregateSignature,
+        domain
+      );
+
+      expect(result).to.be.true;
+    });
+
     it('should fail to verify aggregated signatures - swapped messages', function () {
-      this.timeout(5000)
+      this.timeout(5000);
 
       const domain = Buffer.alloc(8, 0);