IC card and cryptographic communication method between IC cards

• US 20040030896A1
• Filed: 06/10/2003
• Published: 02/12/2004
• Est. Priority Date: 06/10/2002
• Status: Abandoned Application

• Current Assignee: Ken Sakamura, NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation), Noboru Koshizuka
• Original Assignee: Ken Sakamura, NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation), Noboru Koshizuka
• Inventors: Ishii, Kazuhiko, Sakamura, Ken, Mori, Kensaku, Koshizuka, Noboru, Aono, Hiroshi, Hongo, Sadayuki
• Application Number:
  US10/457,523
• Publication Number:
  US 20040030896A1
• Time in Patent Office: Days
• US Class Current: 713/169
• 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 20/40975 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 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 2209/80 Wireless network architectures or network communication protocols for wireless network security H04W12/00
• CPC Class Codes: H04L 9/16 the keys or algorithms being changed during operation
• CPC Class Codes: H04L 9/3273 for mutual authentication network architectures or network communication protocols for achieving mutual authentication in a packet data network H04L63/0869

Abstract

A cryptographic communication method between IC cards in an electronic ticket distribution system is provided, wherein when a server and a user terminal, to each of which an IC card is connected, begin mutual data-communication or when an IC card and, a ticket collecting machine begin mutual data-communication, they both dynamically change encryption algorithms for mutual authentication and for concealment of contents to be transmitted in accordance with information about commonly usable encryption algorithms exchanged at the beginning of a mutual authentication between them, and this procedure at the beginning of the mutual authentication can result in a speedy and secured cryptographic communication between them.

Claims

1. A cryptographic communication method between a first IC card and a second IC card, comprising the steps of:

in a mutual authentication at the beginning of data communication between the first IC card and the second IC card,

exchanging information about a usable encryption algorithm between the first IC card and the second IC card in order to select a commonly usable encryption algorithm between the first IC card and the second IC card;

in the first IC card,

encrypting a plain text data to be sent into an encrypted data by using the selected commonly usable encryption algorithm;

converting the encrypted data into a transmission data with a format required by a predetermined protocol; and

transmitting the transmission data to a communication media; and

in the second IC card,

receiving the transmission data from the communication media;

reversely converting the received transmission data into an encrypted data the same as the original encrypted data sent by the first IC card; and

decrypting the encrypted data into a plain text data the same as the original plain text data sent by the first IC card by using the selected commonly usable encryption algorithm.

2. A cryptographic communication method between IC cards in an electronic ticket distribution system,

wherein the electronic ticket distribution system comprising:

a server having a tamper resistant device, the device which issues and sells electronic tickets, and which has a first function means equivalent to an IC card;

a user terminal having an electrical communication means and having an interface for signal exchange with an IC card, the IC card being connected to the interface and executes purchase and storage of an electric ticket; and

a ticket collecting machine, which has a second function means equivalent to an IC card, for collecting electronic tickets upon their usage;

the method comprising the steps of;

exchanging information about a commonly usable encryption algorithm at the beginning of a mutual authentication between the IC card and the first or the second function means equivalent to an IC card; and

selecting an encryption algorithm commonly usable between the IC card and the first or the second function means equivalent to an IC card as an encryption algorithm to be used for mutual authentication and for concealment of communication data between the IC card and the first or the second function means equivalent to an IC card, according to the information exchanged at the beginning of the mutual authentication between the IC card and the first or the second function means equivalent to an IC card.

3. An IC card comprising:

a selector of encryption algorithm for selecting a commonly usable encryption algorithm as an encryption algorithm for mutual communication with an opposite IC card, according to an exchange of information about a usable encryption algorithm between the opposite IC card at the beginning of a mutual authentication with the opposite IC card;

an encryption means for encrypting a plain text data to be sent into a first encrypted data by using the selected encryption algorithm;

a decryption means for decrypting a second encrypted data received from a communication media by using the selected encryption algorithm;

a converting means for converting the first encrypted data by the encryption means into a first transmission data, in accordance with a predetermined protocol, and for transmitting the first transmission data to the communication media; and

a reversely converting means for reversely converting a second transmission data received from the communication media into the second encrypted data, and for passing the second encrypted data to be sent to the decryption means.