WhatsApp has said that some unknown sources, through the use of Israeli spyware Pegasus, have spied on nearly 1,400 people across the world. There are about two dozen Indians as well among these names. The government has questioned WhatsApp on the reason behind this. However, it has not revealed whether it has purchased the Pegasus software from the Israeli NSO group. As a result, several questions are arising including how to stop the breach of privacy? What is the difference between illegal hacking and surveillance? Why is privacy essential? NewsClick's Prabir Purakayastha answers these questions and more.