The following two types of permissions are relevant for searching:
Permissions for Indexes
When a user starts a search, the system searches only those search indexes for which the user in question has read permission.
If no permissions have been set for a index, the index is included in the search.
Permissions for folders and documents in the repository
Before displaying the results list, the system carries out a permissions check for every document found. The system displays only documents for which the current user has adequate permissions in the results list. If a user does not have read permission for a document, the document in question is not displayed in the results list.
An organization has two business areas. When they carry out a search, employees should find only those documents that belong to their own area.
You create a separate search index for each business area. You then give employees read permission only for the index that relates to their own area.