making blog private, option not there?

I just set up our blog https://www.ctcsandbox.com/blog/ (still working on it).

I need to make it private as it is internal use only. Under privacy I only see these 2 options:

– I would like my blog to be visible to everyone, including search engines (like Google, Sphere, Technorati) and archivers

– I would like to block search engines, but allow normal visitors

How do I make it password protected?

Thanks.