Create one encyption and one decryption with a hardcoded key which will the case need to be handle where key can be a part of incomming data. Most of question in second round was does not makes anysense You need to create a json parser were you are not aware about the JSON structure with using something called as schema . I answered it as I will use hashmap to necessary keys and value using schema (she don't want any android code as she was non-android also she want to see the approach) I don't know what was she looking for as also I am not able to define this as round as whether it is data structure round or whether it is problem-solving.