US Patent 7386732 Integrated system security method

Logic scan based design and electronic fuse (e-fuse) technology are combined to create a circuit macro function that is integrated in a non-critical area of a processor chip or related circuit to provide a new means of securing electronic systems and devices such as computers, appliances, consumer electronics, automobiles, etc. from theft or unauthorized use. Level sensitive scan design (LSSD) techniques are used in conjunction with e-fuses to inhibit or enable system components and sub-components based upon a pre-initialized configuration which must be enabled by a user via password entry.