profile nodeprofile cck handshake contacts hide hidden fields share

I will shortly be creating a 'handshake' module. The idea is that all user data (except username and possibly one or two other items as determined by the site admin) is hidden from all other users. Only the user whose data it is and the site's authorized user administrators can view it. Users will be able to initiate a 'handshake' where the first user indicates (probably via checkbox) which data fields s/he is willing to expose. The second user gets a list of data field titles that are checked (only those checked by user one show up).