05442704 is referenced by 133 patents and cites 5 patents.

A secure memory card includes a microprocessor on a single semiconductor chip which interconnects through an internal bus to a number of non-volatile addressable memory chips. The microprocessor includes an addressable non-volatile memory for storing information including a number of key values and program instruction information. Each chip's memory is organized into a number of blocks, each block including a number of rows of byte locations. Each row of each block further includes a lock bit location, the total number of which provide storage for a lock value uniquely coded to utilize a predetermined characteristic of the memory to ensure data protection. Each memory chip is constructed to include security control logic circuits which include a security access control unit and a volatile access control memory containing a plurality of access control storage elements. Under the control of a predetermined set of instructions, the security access control unit performs a predetermined key validation operation by comparing key values against the bit contents of lock bit locations read out a bit at a time during an authentication procedure with a host computer. After the successful performance of the key validation procedure, the microprocessor sets one of the storage elements of the volatile access control memory for enabling user access to block data.

Title
Secure memory card with programmed controlled security access control
Application Number
8/181691
Publication Number
5442704
Application Date
January 14, 1994
Publication Date
August 15, 1995
Inventor
Thomas O Holtey
Newton
MA, US
Agent
John S Solakian
Faith F Driscoll
Assignee
Bull NH Information Systems
MA, US
IPC
G07F 7/08
H04L 9/32
View Original Source