When you create a site collection from MOSS publishing site template , you get an OOB permission level called “Restricted Read” . The description of Restricted Read in SharePoint is “Can view pages and documents, but cannot view historical versions or review user rights information.”
This is true. But, you can also use this permission level to give users permission to open items in a list without letting them to navigate to the list and enumerate the list items. For example, if you have a document that you want to share with all the portal users, you can upload it to a document library and provide a link from the home page to it and you can still prevent the portal users from browsing the document library directly.
Nice and easy 🙂