Chat functionality (Meteor.js)

I want you to develop a chat application which can be added to another project. I want you to create a chat in [login to view URL] where a registered user is able to chat with another registered user and registered user is able to chat in a group chat of registered users. Create a front-end example for the chat (chat window, person you are chatting with). Try to follow Facebook chat window. Create a secure chat with message encryption or any other security which will prevent unauthorized users from stealing and intercepting chat information. Create an example MongoDB structure with collections for the chat and explain in short sentence why did you do that (link or any other relevant information is recommended). Navigate and develop the project by obeying security article in Meteor Guide.