From a34dbeeb3235ac2e7be13e5d3f56f37b346255ef Mon Sep 17 00:00:00 2001
From: Szymon Szlachtowicz <38212223+Szymx95@users.noreply.github.com>
Date: Mon, 18 Oct 2021 14:57:31 +0200
Subject: [PATCH] Save identity in local storage (#80)

---
 packages/react-chat/src/hooks/useMessenger.ts | 10 ++-
 .../react-chat/src/utils/identityStorage.ts   | 86 +++++++++++++++++++
 2 files changed, 94 insertions(+), 2 deletions(-)
 create mode 100644 packages/react-chat/src/utils/identityStorage.ts

diff --git a/packages/react-chat/src/hooks/useMessenger.ts b/packages/react-chat/src/hooks/useMessenger.ts
index 78fa4bde..5a690979 100644
--- a/packages/react-chat/src/hooks/useMessenger.ts
+++ b/packages/react-chat/src/hooks/useMessenger.ts
@@ -6,6 +6,7 @@ import { ApplicationMetadataMessage } from "status-communities/dist/cjs";
 
 import { uintToImgUrl } from "../helpers/uintToImgUrl";
 import { ChatMessage } from "../models/ChatMessage";
+import { loadIdentity, saveIdentity } from "../utils/identityStorage";
 
 const _MS_PER_DAY = 1000 * 60 * 60 * 24;
 
@@ -136,8 +137,13 @@ export function useMessenger(chatId: string, chatIdList: string[]) {
 
   useEffect(() => {
     const createMessenger = async () => {
-      const identity = Identity.generate();
-
+      // Test password for now
+      // Need design for password input
+      let identity = await loadIdentity("test");
+      if (!identity) {
+        identity = Identity.generate();
+        await saveIdentity(identity, "test");
+      }
       const messenger = await Messenger.create(identity, {
         libp2p: {
           config: {
diff --git a/packages/react-chat/src/utils/identityStorage.ts b/packages/react-chat/src/utils/identityStorage.ts
new file mode 100644
index 00000000..fbe69c93
--- /dev/null
+++ b/packages/react-chat/src/utils/identityStorage.ts
@@ -0,0 +1,86 @@
+import { bufToHex, hexToBuf } from "js-waku/build/main/lib/utils";
+import { Identity } from "status-communities/dist/cjs";
+
+export async function saveIdentity(identity: Identity, password: string) {
+  const salt = window.crypto.getRandomValues(new Uint8Array(16));
+  const wrapKey = await getWrapKey(password, salt);
+
+  const iv = window.crypto.getRandomValues(new Uint8Array(12));
+  const cipher = await window.crypto.subtle.encrypt(
+    {
+      name: "AES-GCM",
+      iv: iv,
+    },
+    wrapKey,
+    identity.privateKey
+  );
+
+  const data = {
+    salt: bufToHex(salt),
+    iv: bufToHex(iv),
+    cipher: bufToHex(cipher),
+  };
+
+  localStorage.setItem("cipherIdentity", JSON.stringify(data));
+}
+
+export async function loadIdentity(
+  password: string
+): Promise<Identity | undefined> {
+  const str = localStorage.getItem("cipherIdentity");
+  if (!str) return;
+  const data = JSON.parse(str);
+
+  const salt = hexToBuf(data.salt);
+  const iv = hexToBuf(data.iv);
+  const cipher = hexToBuf(data.cipher);
+
+  return await decryptIdentity(salt, iv, cipher, password);
+}
+
+async function getWrapKey(password: string, salt: Uint8Array) {
+  const enc = new TextEncoder();
+  const keyMaterial = await window.crypto.subtle.importKey(
+    "raw",
+    enc.encode(password),
+    { name: "PBKDF2" },
+    false,
+    ["deriveBits", "deriveKey"]
+  );
+  return await window.crypto.subtle.deriveKey(
+    {
+      name: "PBKDF2",
+      salt,
+      iterations: 100000,
+      hash: "SHA-256",
+    },
+    keyMaterial,
+    { name: "AES-GCM", length: 256 },
+    true,
+    ["encrypt", "decrypt"]
+  );
+}
+
+async function decryptIdentity(
+  salt: Buffer,
+  iv: Buffer,
+  cipherKeyPair: Buffer,
+  password: string
+): Promise<Identity | undefined> {
+  const key = await getWrapKey(password, salt);
+
+  try {
+    const decrypted = await window.crypto.subtle.decrypt(
+      {
+        name: "AES-GCM",
+        iv: iv,
+      },
+      key,
+      cipherKeyPair
+    );
+
+    return new Identity(new Uint8Array(decrypted));
+  } catch (e) {
+    return;
+  }
+}