Protect Web Service by Setting UriTemplate property in ASP.Net

hello, 

i have publish api using http url on my live server it works fine. the only problem is how can i secure it so it requires password or authentication before any one use it like this is the url to add data.

http://abc.com/service1.svc/Insert/userone/passowr/email

now i do not want any one can use it just call the uri, i want some protection on it so only those person to whom i give access or passcode or some thing can only use it. please advice