Test encryption and decryption

test/xx.test.ts

@@ -1,6 +1,6 @@
 import { expect, assert } from "chai";
 import { Buffer } from 'buffer';
-import { ed25519 } from 'bcrypto';
+import { ed25519, AEAD } from 'bcrypto';
 
 import { XXHandshake, KeyPair } from "../src/xx";
 import { loadPayloadProto, generateEd25519Keys } from "./utils";
@@ -108,4 +108,15 @@ describe("Index", () => {
     await doHandshake(xx);
   });
 
+  it("Test symmetric encrypt and decrypt", async () => {
+    const xx = new XXHandshake();
+    const { nsInit, nsResp } = await doHandshake(xx);
+    const ad = Buffer.from("authenticated");
+    const message = Buffer.from("HelloCrypto");
+
+    xx.encryptWithAd(nsInit.cs1, ad, message);
+    const decrypted = xx.decryptWithAd(nsResp.cs1, ad, message);
+
+    assert(Buffer.from("HelloCrypto").equals(decrypted), "Decrypted text buffer not equal to plaintext buffer");
+  });
 });