password

hi
i’ve got a blog on wordpress.com
my problem is :
i want the visitors of my blog to type a password in order to have the autorization to visit my blog
the solutions given by wrodpress.com are not convenient for me
lots of people will visit the blog, i won’t have the time to autorize everybody
i can not put a password to each page
i am ready to move my blog to wordpress.org if it is necessary, even if i totally dont like technic and dont have lot of time and interest for informatic manipulations
the question is :
with wordpress.org, can i find a solution to oblige people to type a password before visiting the blog, but to allow them, then, to visit all the pages since they have typer once the password
i other terms, is a wordpress.org blog compatible with htaccess for example ?
which servor, then, must i choose ?
will this manipulations remain free for me ?