Assert is a method that can be called on code access permission classes and on the PermissionSet class. You can use Assert to enable your code (and downstream callers) to perform actions that your code has permission to do but its callers might not have permission to do. A security assertion changes the normal process that the runtime performs during a security check. When you assert a permission, it tells the security system not to check the callers of your code for the asserted permission.
Satyapriya NayakPosted Feb 2, 2012, 12:28 AM
Assert is a method that can be called on code access permission classes and on the PermissionSet class. You can use Assert to enable your code (and downstream callers) to perform actions that your code has permission to do but its callers might not have permission to do. A security assertion changes the normal process that the runtime performs during a security check. When you assert a permission, it tells the security system not to check the callers of your code for the asserted permission.
Refer
http://msdn.microsoft.com/en-us/library/91wteedy.aspx
Thanks