Method for issuing IC card storing encryption key information

• US 8,099,771 B2
• Filed: 05/19/2011
• Issued: 01/17/2012
• Est. Priority Date: 05/06/2004
• Status: Expired due to Fees

• Current Assignee: Dai Nippon Printing Company Limited
• Original Assignee: Dai Nippon Printing Company Limited
• Inventors: Handa, Fukio, Yano, Yoshihiro, Chikada, Takayuki, Niwata, Syouzou
• Primary Examiner(s): HENNING, MATTHEW T
• Application Number:
  US13/111,586
• Publication Number:
  US 20110222686A1
• Time in Patent Office: 243 Days
• Field of Search: 726/9, 380/44
• US Class Current: 726/9
• CPC Class Codes: G06Q 20/341 Active cards, i.e. cards including their own processing means, e.g. including an IC or chip
• CPC Class Codes: G06Q 20/355 Personalisation of cards for use
• CPC Class Codes: G06Q 20/40975 using encryption therefor
• CPC Class Codes: G07F 7/1008 Active credit-cards provided with means to personalise their use, e.g. with PIN-introduction/comparison system
• CPC Class Codes: H04L 9/0833 involving conference or group key network architectures or network communication protocols for key management in group communication in a packet data network H04L63/065
• CPC Class Codes: H04L 9/0897 involving additional devices, e.g. trusted platform module [TPM], smartcard or USB

Abstract

It is possible to issue an IC card storing unique encryption key information in such a manner that re-issuing is enabled and sufficient security can be assured. An IC card provider X delivers an IC card having a group code G(A) to a company A and an IC card having a group code G(B) to a company B. When a company staff α inputs a unique personal code P(α) and performs initialization, in the IC card, calculation is performed according to a predetermined algorithm using the P(α) and G(A). Data uniquely determined by the calculation is stored as encryption key information K(α) in the IC card. Even if the company staff α loses the IC card, it is possible to obtain the IC card having the same encryption key information K(α) as before by performing initialization again by using the IC card delivered by the IC card provider X.

Claims

1. A method for executing an encryption/decryption process using IC cards issued to specific individuals belonging to specific groups, respectively, said IC cards having a CPU, a memory and an I/O unit performing transaction of information with respect to the exterior and having stored in the memory, a key information generating program, which, by performing a calculation process based on a predetermined algorithm using at least two pieces of data, generates encryption key information that is uniquely determined by the two pieces of data and an encryption/decryption program for carrying out a process for executing an encryption/decryption process using said encryption key information inside or outside the IC cards, said method comprising an issuing process and an encryption/decryption process:

said issuing process comprising,

a step in which the CPU writes a secret group code, defined for a group to which an individual, to whom the IC card is to be issued, belongs, into the memory based on a write command provided from the exterior via the I/O unit,

a step in which the CPU writes a first secret personal code and a second secret personal code, designated by an individual to whom the IC card is to be issued, into the memory based on a write command provided from the exterior via the I/O unit, and

a step in which the CPU generates a first key table based on the first secret personal code and the secret group code, and a second key table based on the second secret personal code and the secret group code, by executing said key information generating program, and writes both of the key tables as encryption key information into the memory, and

said encryption/decryption process comprising,

a step in which the CPU generates an encryption key, used in encryption or decryption, based on a command provided from the exterior via the I/O unit, said encryption key is obtained by synthesizing a portion of the first key table and a portion of the second key table by executing said encryption/decryption program, and

a step in which the CPU executes an encryption/decryption process using said encryption key or outputs said encryption key to the outside, by executing said encryption/decryption program.

2. The method for executing an encryption/decryption process using IC cards issued according to claim 1, wherein

a routine, which, when being executed on an IC card for a predetermined number of times, records an instruction prohibiting subsequent execution in the IC card, and a routine, which, when the instruction is recorded, prohibits the subsequent execution, are included in the key information generating program.

3. An IC card, used for executing an encryption process or a decryption process using unique encryption key information, the IC card comprising:

a CPU, a memory, and an I/O unit performing transaction of information with respect to the exterior;

there being stored in the memory,

a program for performing a process of storing encryption key information generating data, provided from the exterior, into a first storage location, a second storage location and a third storage location, respectively, inside the memory,

a program for generating a first key table by performing a calculation process based on a predetermined algorithm using a first data stored in the first storage location and a second data stored in the second storage location, said first key table being uniquely determined according to the first data and the second data, and storing said first key table in the memory as encryption key information,

a program for generating a second key table by performing a calculation process based on a predetermined algorithm using a first data stored in the first storage location and a third data stored in the third storage location, said second key table being uniquely determined according to the first data and the third data, and storing said second key table in the memory as encryption key information,

a program for generating an encryption key, used in encryption or decryption, by synthesizing a portion of the first key table and a portion of the second key table, and

a program for executing the encryption process or the decryption process inside the IC card using said encryption key.

4. An IC card, used for executing an encryption process or a decryption process using unique encryption key information, the IC card comprising:

a CPU, a memory, and an I/O unit performing transaction of information with respect to the exterior;

there being stored in the memory,

a program for performing a process of storing encryption key information generating data, provided from the exterior, into a first storage location, a second storage location and a third storage location, respectively, inside the memory,

a program for generating a first key table by performing a calculation process based on a predetermined algorithm using a first data stored in the first storage location and a second data stored in the second storage location, said first key table being uniquely determined according to the first data and the second data, and storing said first key table in the memory as encryption key information,

a program for generating a second key table by performing a calculation process based on a predetermined algorithm using a first data stored in the first storage location and a third data stored in the third storage location, said second key table being uniquely determined according to the first data and the third data, and storing said second key table in the memory as encryption key information,

a program for generating an encryption key, used in encryption or decryption, by synthesizing a portion of the first key table and a portion of the second key table, and

a program for reading out said encryption key for execution of the encryption process or the decryption process outside the IC card.