Merge pull request #2 from NodeFactoryIo/morrigan/xx-symmetric-encryption

xx symmetric encryption

src/xx.ts

@@ -90,11 +90,13 @@ export class XXHandshake {
   private encrypt(k: bytes32, n: uint32, ad: bytes, plaintext: bytes) : bytes {
     const nonce = this.nonceToBytes(n);
     const ctx = new AEAD();
+
     ctx.init(k, nonce);
     ctx.aad(ad);
     ctx.encrypt(plaintext);
 
-    return ctx.final();
+    // Encryption is done on the sent reference
+    return plaintext;
   }
 
   private decrypt(k: bytes32, n: uint32, ad: bytes, ciphertext: bytes) : bytes {
@@ -105,7 +107,8 @@ export class XXHandshake {
     ctx.aad(ad);
     ctx.decrypt(ciphertext);
 
-    return ctx.final();
+    // Decryption is done on the sent reference
+    return ciphertext;
   }
 
   private isEmptyKey(k: bytes32) : boolean {

test/xx.test.ts

@@ -1,6 +1,5 @@
 import { expect, assert } from "chai";
 import { Buffer } from 'buffer';
-import { ed25519 } from 'bcrypto';
 
 import { XXHandshake, KeyPair } from "../src/xx";
 import { loadPayloadProto, generateEd25519Keys } from "./utils";
@@ -108,4 +107,32 @@ 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);
+    assert(!Buffer.from("HelloCrypto").equals(message), "Encrypted message should not be same as plaintext.");
+    const decrypted = xx.decryptWithAd(nsResp.cs1, ad, message);
+
+    assert(Buffer.from("HelloCrypto").equals(decrypted), "Decrypted text not equal to original message.");
+  });
+
+  it("Test multiple messages encryption and decryption", async () => {
+    const xx = new XXHandshake();
+    const { nsInit, nsResp } = await doHandshake(xx);
+    const ad = Buffer.from("authenticated");
+    const message = Buffer.from("ethereum1");
+
+    xx.encryptWithAd(nsInit.cs1, ad, message);
+    const decrypted = xx.decryptWithAd(nsResp.cs1, ad, message);
+    assert(Buffer.from("ethereum1").equals(decrypted), "Decrypted text not equal to original message.");
+
+    const message2 = Buffer.from("ethereum2");
+    xx.encryptWithAd(nsInit.cs1, ad, message2);
+    const decrypted2 = xx.decryptWithAd(nsResp.cs1, ad, message2);
+    assert(Buffer.from("ethereum2").equals(decrypted2), "Decrypted text not equal to original message.");
+  });
 });