This authentication method uses windows authentication in order to access Bonobo Git. If your users are already authenticated in your internal network, this method will use the corresponding accounts without prompting for credentials again.
Set the AuthenticationProvider value in the application web.config according to the following lines.
<appSettings>
<add key="AuthenticationProvider" value="Windows" />
</appSettings>
Git is authenticating to the server via Basic Authentication protocol and sends the password as a part of the request. If you want the communication to be safe you have to introduce SSL in your IIS. With the certificate your application will communicate over HTTPS and it will be encrypted.