Secret SMS is a Messaging application which provides you a secure SMS messaging service. You can send and receive secure SMS via this application. Messages can be sent to a person who has this Secret SMS app and to a person who does not has this app.The security level of sending messages can be customized to either No security, Less Security or High Security.
Are you not sure about whether the message receiver installed Secure SMS app or not? Then please use "No Secu" option