2011/2/11 Michelle Ziegmann <michelle@media.berkeley.edu>

Luke,

Enable the Content Permissions module (part of CCK). Then go to
permissions, and you'll be able to define permissions for every field
individually. As a caution with this though, you'll have to set
permissions every time you add a new field, or users won't be able to
view your content.

With this, any visitor could download the file if he knows the url. Use the private/public options

of File-system under admin/settings

Aries