You can allow downloading files only for registered users. Such files can be displayed for all users or only for registered users. If they will be displayed for all users, public users can see them but they cannot download them. Only registered users can download them.
Go to Components » Phoca Download » Files. Create new item or edit some existing item. Set Access level to e.g. Registered and set Display Unaccessible File to Yes. Now all users can see the file but only registered can download it.
The difference to Categories rights is, in Category you can select specific user, not only the whole group (registered, special).
If Access Rights and Access are set, then two rules are checked when accessing files in category:
First - it is checked if the user is a part of the group
Second - if Access Rights is set, then the user is checked if he/she is selected in the Access Rights.
Access Rights just extend the Access and the user must be a part of the group.


I am not logged in: I cannot access the file
I am logged in as jan: I can access the file (jan is a part of registered and registered is group having viewing access for NewAccessLevel)

I am not logged in: I cannot access the file
I am logged in as jan: I cannot access the file ... because as jan I am not a part of the group Super Users

I am not logged in: I cannot access the file
I am logged in as jan: I can access the file because jan is in group NewAccessLevel (in this case only group is checked as the user is not set)