Access control: Selective inefficiency.
No security measure that seeks to allow access to some and prevent access by others can ever be perfect. All a security system can hope to accomplish is to impose a small inefficiency upon those that are allowed access while imposing a large inefficiency upon those that are not permitted access.
As the value of the protected asset increases, larger inefficiencies will be tolerated for those permitted access in exchange for even larger increases in inefficiency for those not permitted access.
