From 2f67a3baffc085d61b057f9fdb5ab404bfd70a1b Mon Sep 17 00:00:00 2001
From: "fryorcraken.eth" <git@fryorcraken.xyz>
Date: Fri, 8 Dec 2023 21:52:16 +1100
Subject: [PATCH] feat: new `verifySignature`

To enable comparison with expected public key
---
 package-lock.json                             | 24 +++++++++++++++++--
 packages/message-encryption/package.json      |  3 ++-
 .../message-encryption/src/decoded_message.ts | 13 ++++++++++
 packages/message-encryption/src/ecies.spec.ts |  2 ++
 .../message-encryption/src/symmetric.spec.ts  |  2 ++
 5 files changed, 41 insertions(+), 3 deletions(-)

diff --git a/package-lock.json b/package-lock.json
index 55056d23ce..9efc1e5513 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -26179,7 +26179,8 @@
         "@waku/proto": "0.0.5",
         "@waku/utils": "0.0.13",
         "debug": "^4.3.4",
-        "js-sha3": "^0.9.2"
+        "js-sha3": "^0.9.2",
+        "uint8arrays": "^5.0.0"
       },
       "devDependencies": {
         "@rollup/plugin-commonjs": "^25.0.7",
@@ -26200,6 +26201,14 @@
         "node": ">=18"
       }
     },
+    "packages/message-encryption/node_modules/uint8arrays": {
+      "version": "5.0.0",
+      "resolved": "https://registry.npmjs.org/uint8arrays/-/uint8arrays-5.0.0.tgz",
+      "integrity": "sha512-RWO7gR4x6syxnKDfZO8mDCsaaYs1/BqZCxlHgrcRge50E9GTnLmtoA4kwFSGIL4s3dQkryeTkvtG6oEFEya3yg==",
+      "dependencies": {
+        "multiformats": "^12.0.1"
+      }
+    },
     "packages/message-hash": {
       "name": "@waku/message-hash",
       "version": "0.1.9",
@@ -29529,7 +29538,18 @@
         "mocha": "^10.2.0",
         "npm-run-all": "^4.1.5",
         "process": "^0.11.10",
-        "rollup": "^4.6.0"
+        "rollup": "^4.6.0",
+        "uint8arrays": "^5.0.0"
+      },
+      "dependencies": {
+        "uint8arrays": {
+          "version": "5.0.0",
+          "resolved": "https://registry.npmjs.org/uint8arrays/-/uint8arrays-5.0.0.tgz",
+          "integrity": "sha512-RWO7gR4x6syxnKDfZO8mDCsaaYs1/BqZCxlHgrcRge50E9GTnLmtoA4kwFSGIL4s3dQkryeTkvtG6oEFEya3yg==",
+          "requires": {
+            "multiformats": "^12.0.1"
+          }
+        }
       }
     },
     "@waku/message-hash": {
diff --git a/packages/message-encryption/package.json b/packages/message-encryption/package.json
index 1faca460f2..11b16199ef 100644
--- a/packages/message-encryption/package.json
+++ b/packages/message-encryption/package.json
@@ -81,7 +81,8 @@
     "@waku/proto": "0.0.5",
     "@waku/utils": "0.0.13",
     "debug": "^4.3.4",
-    "js-sha3": "^0.9.2"
+    "js-sha3": "^0.9.2",
+    "uint8arrays": "^5.0.0"
   },
   "devDependencies": {
     "@rollup/plugin-commonjs": "^25.0.7",
diff --git a/packages/message-encryption/src/decoded_message.ts b/packages/message-encryption/src/decoded_message.ts
index 05ba932a87..80418330c7 100644
--- a/packages/message-encryption/src/decoded_message.ts
+++ b/packages/message-encryption/src/decoded_message.ts
@@ -3,6 +3,7 @@ import {
   proto
 } from "@waku/core/lib/message/version_0";
 import type { IDecodedMessage } from "@waku/interfaces";
+import { equals } from "uint8arrays/equals";
 
 export class DecodedMessage
   extends DecodedMessageV0
@@ -24,4 +25,16 @@ export class DecodedMessage
   get payload(): Uint8Array {
     return this._decodedPayload;
   }
+
+  /**
+   * Verify the message's signature against the public key.
+   *
+   * @returns true if the signature matches the public key, false if not or if no signature is present.
+   */
+  verifySignature(publicKey: Uint8Array): boolean {
+    if (this.signaturePublicKey) {
+      return equals(this.signaturePublicKey, publicKey);
+    }
+    return false;
+  }
 }
diff --git a/packages/message-encryption/src/ecies.spec.ts b/packages/message-encryption/src/ecies.spec.ts
index 3545a40481..2bfe23c67a 100644
--- a/packages/message-encryption/src/ecies.spec.ts
+++ b/packages/message-encryption/src/ecies.spec.ts
@@ -34,6 +34,7 @@ describe("Ecies Encryption", function () {
           expect(result.version).to.equal(1);
           expect(result?.payload).to.deep.equal(payload);
           expect(result.signature).to.be.undefined;
+          expect(result.verifySignature(new Uint8Array())).to.be.false;
           expect(result.signaturePublicKey).to.be.undefined;
         }
       )
@@ -78,6 +79,7 @@ describe("Ecies Encryption", function () {
           expect(result.version).to.equal(1);
           expect(result?.payload).to.deep.equal(payload);
           expect(result.signature).to.not.be.undefined;
+          expect(result.verifySignature(alicePublicKey)).to.be.true;
           expect(result.signaturePublicKey).to.deep.eq(alicePublicKey);
         }
       )
diff --git a/packages/message-encryption/src/symmetric.spec.ts b/packages/message-encryption/src/symmetric.spec.ts
index 0a6370c0f6..cd604eb7d0 100644
--- a/packages/message-encryption/src/symmetric.spec.ts
+++ b/packages/message-encryption/src/symmetric.spec.ts
@@ -31,6 +31,7 @@ describe("Symmetric Encryption", function () {
           expect(result.version).to.equal(1);
           expect(result?.payload).to.deep.equal(payload);
           expect(result.signature).to.be.undefined;
+          expect(result.verifySignature(new Uint8Array())).to.be.false;
           expect(result.signaturePublicKey).to.be.undefined;
         }
       )
@@ -66,6 +67,7 @@ describe("Symmetric Encryption", function () {
           expect(result.version).to.equal(1);
           expect(result?.payload).to.deep.equal(payload);
           expect(result.signature).to.not.be.undefined;
+          expect(result.verifySignature(sigPubKey)).to.be.true;
           expect(result.signaturePublicKey).to.deep.eq(sigPubKey);
         }
       )