Contactless IC card, responding method, and program therefor

• US 20020046226A1
• Filed: 10/15/2001
• Published: 04/18/2002
• Est. Priority Date: 10/13/2000
• Status: Active Grant

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Kawano, Shinji, Nakabe, Futoshi, Masaki, Tadakatsu
• Granted Patent: US 7,016,924 B2
• Time in Patent Office: Days
• US Class Current: 708/250
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10059 transponder driven

Abstract

Provision of a high-grade random number by means of a simple configuration enables to provide a contactless IC card, a responding method, and a program therefore; those can control the collision of the initial responses in minimum. The contactless IC card, the responding method and the program comprise the provisional random number generating means for generating a provisional random number according to a part of operations to be used for the generation of a random number, the provisional random number storage means for storing the provisional random number generated by the provisional random number storage means, and the random number generating means for generating a random number on the basis of the provisional random number at receiving the request from the reader/writer.

Claims

1. A contactless IC card responding to a request sent from a reader/writer by using a value calculated based on random numbers, which comprising:

provisional random number generating means for generating a provisional random number according to a part of operations to be used for generating a random number;

provisional random number storage means for storing the provisional random number generated by the provisional random number generating means; and

random number generating means for generating a random number on the basis of the stored provisional random number at the time of receiving the request from the reader/writer.

2. A contactless IC card according to claim 1, wherein the calculated value is a response timing calculated on the basis of slot numbers included in the request and the random number generated by the random number generating means.

3. A contactless IC card according to claim 1, wherein the operations for generating the provisional random number are not concerned with the request, and the operations for generating the random number are determined by the request.

4. A contactless IC card according to claim 2, which further comprising a plurality of provisional random number storage means, and making the response to the request of the reader/writer by using a plurality of stored provisional random numbers in sequential order.

5. A contactless IC card according to claim 2, which further comprising self-response timing judging means for judging if there is a specific time until the timing to respond by the card itself, and

wherein the provisional random number generating means generates the provisional random number if the self-response timing judging means judges that there is the specific time until the response timing.

6. A contactless IC card according to claim 2, wherein the provisional random number storage means is nonvolatile,

the provisional random number generating means generates the provisional random number at the end of the communication and stores the provisional random number in the nonvolatile provisional random number storage means, and

the random number generating means generates a random number on the basis of the provisional random number stored in the nonvolatile provisional random number storage means at receiving the request.

7. A contactless IC card according to claim 2, which comprising:

an interruption flag representing that the processing for generating provisional random numbers should be interrupted when the request from the reader/writer is received in the middle of the provisional random number generation; and

a processing flag representing a position from which the provisional random number generation should be restarted after the end of the response to the request, and

wherein the provisional random number generation should be interrupted or restarted on the basis of the interruption flag and the processing flag.

8. A contactless IC card according to claim 7, which further comprising specific slot number storing means for storing specific value;

and

which interrupts the processing for generating provisional random numbers when the request from the reader/writer is received in the middle of the provisional random number generation and then makes a response to that request.

9. A contactless IC card according to claim 8, wherein a value stored in the specific slot number storing means is 1.

10. A responding method of contactless IC card responding to a request sent from a reader/writer by using a value calculated based on a random number, which comprising:

generating a provisional random number according to a part of operations to be used for generating a random number; and

generating a random number on the basis of the provisional random number at the time of receiving the request from the reader/writer.

11. A program executed by a contactless IC card responding to a request sent from a reader/writer by using a value calculated based on a random number, which comprising:

generating a provisional random number according to a part of operations to be used for generating a random number; and

generating a random number on the basis of the provisional random number at the time of receiving the request from the reader/writer.

12. A recording medium readable for a computer and storing a program executed by a contactless IC card responding to a request sent from a reader/writer by using a value calculated based on a random number, which comprising:

generating a provisional random number according to a part of operations to be used for generating a random number; and

generating a random number on the basis of the provisional random number at the time of receiving the request from the reader/writer.