Method and apparatus for initialization of cryptographic terminal

• US 5,745,576 A
• Filed: 05/17/1996
• Issued: 04/28/1998
• Est. Priority Date: 05/17/1996
• Status: Expired due to Term

• Current Assignee: Visa International Service Association (Visa, Inc.)
• Original Assignee: Visa International Service Association (Visa, Inc.)
• Inventors: Hite, Richard K., Abraham, Dennis G.
• Primary Examiner(s): Barron, Jr., Gilberto
• Application Number:
  US08/650,888
• Time in Patent Office: 711 Days
• Field of Search: 380/21, 380/23, 380/24, 380/25, 902/2
• US Class Current: 705/73
• CPC Class Codes: G06Q 20/382 insuring higher security of transaction
• CPC Class Codes: G06Q 20/3829 involving key management
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 9/0847 involving identity based encryption [IBE] schemes
• CPC Class Codes: H04L 9/3271 using challenge-response

Abstract

The present invention provides a method and apparatus for initializing cryptographic terminals in a cryptographic system. The invention provides a base key that is common to all controllers produced by a manufacturer of cryptographic systems. The base key is installed by the manufacturer of cryptographic terminals in each controller prior to shipment of the controllers. The base key is used only for the purposes of initialization of cryptographic terminals, and is not used for normal operations. Each cryptographic terminal that is to be used with any of the controllers containing the common base key is provided with an initial key by the manufacturer of the terminal. Each initial key is derived from the particular terminal'"'"'s serial number and the common base key. The initial key is used only for initialization purposes and not for system operation. The terminal and controller establish communications in a normal manner using whatever communication protocol is appropriate for them. Upon installation, the controller and terminal enter into communications whereby the controller is able to securely determine the initial key contained in the terminal since the controller contains the base key.

Claims

1. A method for initializing a cryptographic terminal in a cryptographic system with an operational key comprising the steps of:

defining a base key for a cryptographic system;

storing said base key in a controller of said cryptographic system;

deriving an initial terminal key for a cryptographic terminal having a unique identifying number, said initial terminal key derived using said base key and said unique identifying number;

storing said initial terminal key in said cryptographic terminal;

establishing communication between said controller and said cryptographic terminal;

sending said unique identifying number from said cryptographic terminal to said controller;

at said controller, using a first processing means, deriving an expected initial terminal key using said unique identifying number and said base key;

encrypting a challenge message at said controller using said expected initial terminal key and transmitting said encrypted challenge message to said cryptographic terminal;

at said cryptographic terminal, using a second processing means, decrypting said encrypted challenge message using said initial terminal key;

encrypting a response message at said cryptographic terminal using said initial terminal key and transmitting said encrypted response message to said controller;

comparing said encrypted response message at said controller to an expected response message;

verifying said cryptographic terminal as an authentic cryptographic terminal when said response message matches said expected response message.

2. The method of claim 1 wherein said step of comparing said encrypted response message at said controller to an expected response message includes decrypting said encrypted response message at said controller.

3. The method of claim 1 further including the steps of:

encrypting a terminal challenge message at said cryptographic terminal using said initial terminal key and transmitting said encrypted terminal challenge message to said controller;

decrypting said encrypted terminal message at said controller using said expected initial terminal key;

encrypting a controller response message at said controller using said expected initial terminal key and transmitting said encrypted controller response to said cryptographic terminal;

decrypting said encrypted controller response message at said cryptographic terminal using said initial terminal key and comparing said controller response message to an expected controller response message;

verifying said controller as an authentic controller when said controller response message matches said expected controller response message.

4. The method of claim 1 further including the steps of:

encrypting an operation key at said controller using said expected initial terminal key and transmitting said encrypted operation key to said cryptographic terminal when said cryptographic terminal has been verified as an authentic terminal;

decrypting said encrypted operation key at said cryptographic terminal using said initial terminal key and using said operation key to encrypt messages between said controller and said cryptographic terminal.

5. The method of claim 1 wherein said base key is stored in said controller in a physically secure manner.

6. The method of claim 1 wherein said initial terminal key is derived using a Derived Unique Key Per Transaction (DUKPT) method.

7. The method of claim 1 wherein said expected initial terminal key is derived using a DUKPT method.

8. The method of claim of claim 1 wherein said step of deriving said initial terminal key includes the use of a transaction count.

9. The method of claim 1 wherein said step of deriving said expected initial terminal key includes the use of a transaction count.

10. A system for initializing a cryptographic terminal in a cryptographic system comprising:

a controller for storing a base key and for deriving an expected initial terminal key using said base key and a unique identifying number from a cryptographic terminal, said controller comprising;

a controller input device for inputting said base key;

a controller memory coupled to said controller input device for storing said base key;

a controller encrypter/decrypter coupled to said controller memory and said controller input device;

a controller input/output port coupled to said controller encrypter/decrypter;

a cryptographic terminal coupled to said controller comprising;

a terminal input device for inputting a unique identifying number of said cryptographic terminal;

a terminal memory storing an initial terminal key, said initial terminal key derived using said base key and said unique identifying number;

a terminal encrypter/decrypter coupled to said terminal memory and said terminal input device;

a terminal input/output port coupled to said terminal controller encrypter/decrypter.

11. The system of claim 10 wherein said controller input device comprises a keypad.

12. The system of claim 10 wherein said terminal input device comprises a keypad.

13. The system of claim 10 wherein said controller encrypter/decrypter is implemented in a microprocessor.

14. The system of claim 10 wherein said terminal encrypter/decrypter is implemented in a microprocessor.

15. An article of manufacture comprising:

a computer usable medium having computer readable program code means embodied thereon for causing an initialization process between a controller and a cryptographic terminal, the computer readable program code means in said article of manufacture comprising;

computer readable program code means for causing a computer to store a base key in a controller memory of said controller;

computer readable program code means for causing a computer to receive a unique identifying number from said cryptographic terminal;

computer readable program code means for causing a computer to derive an expected initial terminal key using said base key and said unique identifying number;

computer readable program code means for causing a computer to encrypt a controller challenge using said expected initial terminal key;

computer readable program code means for causing a computer to transmit said encrypted challenge to said cryptographic terminal;

computer readable program code means for causing a computer to receive an encrypted terminal response, said encrypted terminal response encrypted using an initial terminal key stored in said cryptographic terminal and derived from said unique identifying number and said base key;

computer readable program code means for causing a computer to compare an expected response with said encrypted terminal response;

computer readable program code means for causing a computer to validate said cryptographic terminal when said decrypted response matches said expected response.

16. The article of manufacture of claim 15 further including:

computer readable program code means for causing a computer to decrypt said encrypted terminal response using said expected initial terminal key before comparing said expected response with said encrypted terminal response.

17. The article of manufacture of claim 15 further including:

computer readable program code means for causing a computer to encrypt an operation key and transmit said operation key to said cryptographic terminal.

18. The article of manufacture of claim 15 further including:

computer readable program code means for causing a computer to derive said expected initial terminal key using said base key, said unique identifying number, and a transaction count.

19. The article of manufacture of claim 15 further including:

computer readable program code means for causing a computer to receive an encrypted terminal challenge from said cryptographic terminal, said encrypted terminal challenge encrypted using said initial terminal key;

computer readable program code means for causing a computer to decrypt said encrypted terminal challenge using said expected initial terminal key;

computer readable program code means for causing a computer to encrypt a controller response encrypted using said expected initial terminal key;

computer readable program code means for causing a computer to transmit said encrypted controller response to said cryptographic terminal.

20. An article of manufacture comprising:

a computer usable medium having computer readable program code means embodied thereon for causing an initialization process between a controller and a cryptographic terminal, the computer readable program code means in said article of manufacture comprising;

computer readable program code means for causing a computer to store an initial terminal key in a terminal memory of said cryptographic terminal, said initial terminal key derived using a base key and a unique identifying number of said cryptographic terminal;

computer readable program code means for causing a computer to send said unique identifying number from said cryptographic terminal to a controller;

computer readable program code means for causing a computer to receive an encrypted challenge from said controller, said encrypted challenge encrypted using an expected terminal key derived using said base key and said unique identifying number;

computer readable program code means for causing a computer to decrypt said controller challenge using said initial terminal key;

computer readable program code means for causing a computer to encrypt a terminal response to said controller challenge using said initial terminal key;

computer readable program code means for causing a computer to transmit said encrypted terminal response to said controller;

computer readable program code means for causing a computer to decrypt said terminal response using said expected initial terminal key.

21. The article of manufacture of claim 20 further including:

computer readable program code means for causing a computer to receive an encrypted operation key from said controller;

computer readable program code means for causing a computer to decrypt said encrypted operation key using said initial terminal key.

22. The article of manufacture of claim 20 further including:

computer readable program code means for causing a computer to encrypt a terminal challenge using said initial terminal key;

computer readable program code means for causing a computer to transmit said encrypted terminal challenge to said controller;

computer readable program code means for causing a computer to receive an encrypted controller response from said controller, said encrypted controller response encrypted using an expected initial terminal key derived using said base key and said unique identifying number;

computer readable program code means for causing a computer to decrypt said encrypted controller response;

computer readable program code means for causing a computer to compare said controller response with an expected controller response;

computer readable program code means for causing a computer to validate said controller when said controller response matches said expected controller response.

23. The article of manufacture of claim 20 further including:

computer readable program code means for causing a computer to derive said initial terminal key using said base key, said unique identifying number, and a transaction count.