US 5,745,576 A · Method and apparatus for initialization of cryptographic terminal

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.

Claims23

Dependent claims

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.

9 more elements

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.

6 more elements

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.

5 more elements

Dependencies are inferred from the claim text.

Method and apparatus for initialization of cryptographic terminal

Life of this patent

Method and apparatus for initialization of cryptographic terminal

Life of this patent

Abstract

Claims23