Method of updating encryption device monitor code in a multichannel data encryption system

• US 5,123,047 A
• Filed: 01/25/1991
• Issued: 06/16/1992
• Est. Priority Date: 12/09/1988
• Status: Expired due to Fees

• Current Assignee: The Exchange System Limited Partnership
• Original Assignee: The Exchange System Limited Partnership
• Inventors: Rosenow, Michael J.
• Primary Examiner(s): GREGORY, BERNARR E
• Application Number:
  US07/649,210
• Time in Patent Office: 508 Days
• Field of Search: 380/4, 380/25, 380/44, 380/49, 380/9, 380/23, 380/24, 380/29, 380/30, 380/50
• US Class Current: 713/191
• CPC Class Codes: G06F 11/0757 by exceeding a time limit, i.e. time-out, e.g. watchdogs
• CPC Class Codes: G06F 11/1415 at system level
• CPC Class Codes: G06F 11/2015 Redundant power supplies power supply failure G06F1/30
• CPC Class Codes: G06F 11/2023 Failover techniques
• CPC Class Codes: G06F 11/2038 with a single idle spare processing component
• CPC Class Codes: G06F 9/4812 by interrupt, e.g. masked
• CPC Class Codes: G07F 7/1016 Devices or methods for securing the PIN and other transaction-data, e.g. by encryption arrangements for secret communication, see H04L9/00
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 63/083 using passwords cryptographic mechanisms or cryptographic arrangements for entity authentication using a predetermined code H04L9/3226

Abstract

An apparatus and method for loading a replacement computer program into a data encryption device having a central processing unit and a memory. The central processing unit is responsive to interrupt requests and operatively connected to a communications port. The memory has memory locations, and is partitioned into a data memory space and a program memory space, with the program memory space being read-only. The replacement computer program has a main entry point, and a load address which is the memory location at which the replacement computer program is to be loaded. When the occurence of an interrupt request, indicating a request to load the replacement computer porgram into the memory, is detected, the execution of a loaded computer program at a memory location is interrupted. Control is transferred to an interrupt routine. The replacement computer program is received through the communications port, and stored in the memory. The replacement computer program replaces the loaded computer program. Before storing the replacement computer program, the memory is partititoned so that the load address is in the data memory space, and after storing the replacement computer program, the memory is partititioned so that the load address is in the program memory space. Upon completion of the interrupt routine, control is transferred from the interrupt routine to the main entry point of the replacement computer program such that the interrupt routine does not return to the interrupted memory location.

Claims

1. A method for loading a replacement computer program into a data encryption device having a central processing unit and a memory, the central processing unit responsive to interrupt requests and operatively connected to a communications port, the memory having memory locations, the replacement computer program having a main entry point, comprising the steps of:

detecting the occurrence of an interrupt request, the interrupt request indicating a request to load the replacement computer program into the memory;

interrupting the execution of a loaded computer program at a memory location;

transferring control to an interrupt routine;

receiving the replacement computer program through the communications port;

storing the replacement computer program in the memory; and

upon completion of the interrupt routine, transferring control from the interrupt routine to the main entry point of the replacement computer program whereby the interrupt routine does not return to the interrupted memory location.

2. The method of claim 1 wherein the step of storing the replacement computer program replaces the loaded computer program.

3. The method of claim 1 wherein the memory is partitioned into a data memory space and a program memory space, the program memory space being read-only, the replacement computer program having a load address, the load address being the memory location at which the replacement computer program is to be loaded, the method including the steps of:

before storing the replacement computer program, partitioning the memory so that the load address is in the data memory space; and

after storing the replacement computer program, partitioning the memory so that the load address is in the program memory space.

4. The method of claim 1 wherein the communications port is operatively connected to a front-end control unit and wherein the step of receiving the replacement computer program includes the step of transmitting the replacement computer program from the front-end control unit to the communications port.

5. A method for replacing a loaded computer program with a replacement computer program in a data encryption device, the data encryption device having a central processing unit and a memory, the central processing unit executing the loaded computer program, the central processing unit being responsive to interrupt requests and operatively connected to a communications port, the method comprising the steps of:

detecting the occurrence of an interrupt request, the interrupt request indicating a request to load the replacement computer program into the memory;

receiving the replacement computer program through the communications port; and

storing the replacement computer program in the memory to replace the loaded computer program.

6. The method of claim 5 wherein the memory has memory locations, the memory being partitioned into a data memory space and a program memory space, the program memory space being read-only, the replacement computer program having a load address, the load address being the memory location at which the replacement computer program is to be loaded, the method including the steps of:

before storing the replacement computer program, partitioning the memory so that the load address is in the data memory space; and

after storing the replacement computer program, partitioning the memory so that the load address is in the program memory space.

7. The method of claim 5 wherein the communications port is operatively connected to a front-end control unit and wherein the step of receiving the replacement computer program includes the step of transmitting the replacement computer program from the front-end control unit to the communications port.

8. An apparatus for loading a data encryption computer program into a data encryption device, the data encryption computer program having computer instructions, the apparatus comprising:

a central processing unit, the central processing unit having a register;

a memory operatively connected to the central processing unit, the memory containing a previously loaded computer program, the previously loaded computer program having computer instructions;

means for generating a load program interrupt request, the central processing unit being responsive to the load program interrupt request;

a communications port for receiving the computer instructions of the data encryption computer program, the communications port operatively connected to the central processing unit;

means for reading the computer instructions of the data encryption computer program from the communications port into the register of the central processing unit; and

means for storing the computer instructions in the register into the memory to replace the computer instructions of the previously loaded computer program.

9. The apparatus of claim 8 wherein the central processing unit is the DS5000 central processing unit.

10. The apparatus of claim 8 including a bi-directional FIFO buffer having two ends, the first end of the FIFO buffer operatively connected to the communications port.

11. The apparatus of claim 10 including a front-end control unit for sending the computer instructions of the data encryption computer program to the second end of the bi-directional FIFO buffer.