Security and Protection (PowerPivot for SharePoint)
This section provides information about securing PowerPivot data access and server operations in a SharePoint 2010 farm.
Plan PowerPivot Authentication and Authorization
Configuring Kerberos Authentication for Microsoft SharePoint 2010 Products (White Paper)
Microsoft SQL Server PowerPivot Security Planning and Design (White Paper)
Securing a PowerPivot Workbook
Create a trusted location for PowerPivot sites
Change Service Accounts and Passwords (PowerPivot for SharePoint)