SX User Name Security prevents WordPress from showing your real Login by overriding the body_class function, User Nicename, Nickname and Display Name.
"SX User Name Security" hides your author nicename and ID (body_class function).
When a user Nickname or Display Name are equals to Login, the plugin uses a random value instead.
During registration, WordPress won't use the same Display Name and Login for new users : "SX User Name Security" uses a random value.
An administrator is able to secure all users at once