Classifying documents in a site / doc lib based on public or private or confidential type in a DMS

hi,

hi,

i have an requirement to classify the documents in a doc lib  as confidential, private,public in my corp. intranet Doc.Mgmnt System portal.

i would like to get some pointers how to implement this. if i simply create a site column column in  and it will be available as

mentioned  above types while  uploading a doc will that suffice? in this case, if a user who is NOT supposed to view/search the confidential  documents mustNOT be allowed to search/view.

how can i restrict a user by not allowing to view/search confidential and private.

one approach i was thinking that (a) i create a site policy  feature(b) create a  restricted content type (c) associate this restricted content type to the doc lib.

 is this approach correct? if yes, how can i create a  restricted content type  in a  site. i did not get any help after search in google / bing

any help is appreciated.