Can you grant permission to a user to only have access to one file and not the entire site?
here are steps:
- Go to that Document Library > go to the File > from the Actions Menu > select Manage Permissions
- from Ribion > click on Action Menu > click on stop inheriting permissions
- Now you can remove everybody and add the user directly which you want give permissions
Note dont select a SharePoint group rather add the user directly. Otherwise user gets permission on other areas as well.
As Robert said, you can do this pretty easily.
- Find the document you want to limit permission on.
- To the right of the name, click the twiddle to open the menu for the item.
- Select Manage Permissions near the bottom of the menu.
- In the ribbon, select Stop Inheriting Permission
- Add or delete permissions as needed.
Hope this helps.