Implemented FxA

app/fxa.js

@@ -0,0 +1,44 @@
+import jose from 'node-jose';
+import { arrayToB64, b64ToArray } from './utils';
+
+const encoder = new TextEncoder();
+
+export async function prepareWrapKey(storage) {
+  const keystore = jose.JWK.createKeyStore();
+  const keypair = await keystore.generate('EC', 'P-256');
+  storage.set('fxaWrapKey', JSON.stringify(keystore.toJSON(true)));
+  return jose.util.base64url.encode(JSON.stringify(keypair.toJSON()));
+}
+
+export async function getFileListKey(storage, bundle) {
+  const keystore = await jose.JWK.asKeyStore(
+    JSON.parse(storage.get('fxaWrapKey'))
+  );
+  const result = await jose.JWE.createDecrypt(keystore).decrypt(bundle);
+  const jwks = JSON.parse(jose.util.utf8.encode(result.plaintext));
+  const jwk = jwks['https://identity.mozilla.com/apps/send'];
+  const baseKey = await crypto.subtle.importKey(
+    'raw',
+    b64ToArray(jwk.k),
+    { name: 'HKDF' },
+    false,
+    ['deriveKey']
+  );
+  const fileListKey = await crypto.subtle.deriveKey(
+    {
+      name: 'HKDF',
+      salt: new Uint8Array(),
+      info: encoder.encode('fileList'),
+      hash: 'SHA-256'
+    },
+    baseKey,
+    {
+      name: 'AES-GCM',
+      length: 128
+    },
+    true,
+    ['encrypt', 'decrypt']
+  );
+  const rawFileListKey = await crypto.subtle.exportKey('raw', fileListKey);
+  return arrayToB64(new Uint8Array(rawFileListKey));
+}