Represents a user or group that can be assigned permissions in Microsoft SharePoint Foundation to control security.
Assembly: Microsoft.SharePoint (in Microsoft.SharePoint.dll)
Available in Sandboxed Solutions: Yes
Available in SharePoint Online
When a user or group is added to a site, the user or group is the principal. The SPPrincipal object can represent one of the following types of users or groups:
Non-Windows user (provided through ASP.NET membership provider)
Non-Windows group (provided through ASP.NET roles provider)