[ii] Patent Number: 5,774,545  Date of Patent: Jun. 30, 1998
 METHOD AND APPARATUS FOR ENHANCING SECURITY IN AND DISCOURAGING THEFT OF VLSI AND ULSI DEVICES
 Inventor: Partha Raghavachari, Chicago, 111.
 Assignee: Lucent Technologies Inc., Murray Hill, N.J.
 Appl. No.: 623,271
 Filed: Mar. 28, 1996
 Int. CI. 11041. 9/00
 U.S. CI 380/4; 380/23
 Field of Search 380/4, 23; 365/185.33
 References Cited
U.S. PATENT DOCUMENTS
4,926,480 5/1990 Chaum 380/23
VLSI and ULSI devices like microprocessors and DRAM devices are prone to large scale theft from lactones and warehouses. A proposed method ol reducing the theft incorporates a small amount ol non-volatile flash memory in these devices. The flash memory contains password, device serial number and user identification information. On power-up, the device initiates an encrypted password verification session through a standard interlace. II the user supplied password lails, the device's operational ports (any data or control output buses) are tri-stated, thus making the device unusable. The device serial number and user identification information are usefiil in determining ownership ol stolen devices when recovered.
25 Claims, 9 Drawing Sheets