New sticker creator button

ts/textsecure/authorizeArtCreator.ts

@@ -0,0 +1,59 @@
+// Copyright 2022 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { promisify } from 'util';
+
+import { SignalService as Proto } from '../protobuf';
+import { calculateAgreement, generateKeyPair } from '../Curve';
+import { encryptAttachment, deriveSecrets } from '../Crypto';
+import * as Bytes from '../Bytes';
+
+const PROVISIONING_INFO = 'Art Service Provisioning Message';
+
+export type AuthorizeArtCreatorOptionsType = Readonly<{
+  token: string;
+  pubKeyBase64: string;
+}>;
+
+export async function authorizeArtCreator({
+  token,
+  pubKeyBase64: theirPubKeyBase64,
+}: AuthorizeArtCreatorOptionsType): Promise<void> {
+  const { server } = window.textsecure;
+  if (!server) {
+    throw new Error('Server not ready');
+  }
+
+  const auth = await server.getArtAuth();
+
+  const ourKeys = generateKeyPair();
+  const theirPubKey = Bytes.fromBase64(theirPubKeyBase64);
+
+  const secret = calculateAgreement(theirPubKey, ourKeys.privKey);
+  const [aesKey, macKey] = deriveSecrets(
+    secret,
+    new Uint8Array(64),
+    Bytes.fromString(PROVISIONING_INFO)
+  );
+  const keys = Bytes.concatenate([aesKey, macKey]);
+
+  const { ciphertext } = encryptAttachment(
+    Proto.ArtProvisioningMessage.encode({
+      ...auth,
+    }).finish(),
+    keys
+  );
+
+  const envelope = Proto.ArtProvisioningEnvelope.encode({
+    publicKey: ourKeys.pubKey,
+    ciphertext,
+  }).finish();
+
+  const socket = await server.getArtProvisioningSocket(token);
+
+  try {
+    await promisify(socket.sendBytes).call(socket, Buffer.from(envelope));
+  } finally {
+    socket.close(1000, 'goodbye');
+  }
+}