encryptPayload function
Implementation
Uint8List encryptPayload(Uint8List data) {
final iv = IV.fromSecureRandom(16);
final encrypter = Encrypter(AES(aesKey, mode: AESMode.cbc));
final encrypted = encrypter.encryptBytes(data, iv: iv);
return Uint8List.fromList([...iv.bytes, ...encrypted.bytes]);
}