Non-contact IC card

• US 20040031857A1
• Filed: 08/05/2003
• Published: 02/19/2004
• Est. Priority Date: 08/15/2002
• Status: Active Grant

• Current Assignee: NEC Corporation, Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Sato, Hideo
• Granted Patent: US 7,134,604 B2
• Time in Patent Office: Days
• US Class Current: 235/492
• 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: 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

Abstract

In a non-contact IC card for performing communication with a reader/writer, an encryption block having a DES (data encryption standard) block for performing an encryption operation in accordance with a public key encryption algorithm and an ECC/SHA1 (elliptic curve cryptosystem/secure hash algorithm 1) block for performing an encryption operation in accordance with a common key encryption algorithm are incorporated into an IC chip. A CPU having a built-in clock gear causes a change of the operation frequency of the non-contact IC card. The communication operation with the reader/writer and the encryption operations performed by the encryption block are performed at different operation frequencies.

Claims

1. A non-contact IC card for communicating data with a reader/writer in a contactless manner, said non-contact IC card comprising:

encryption means having a public key encryption processor for performing a public key encryption operation, and a common key encryption processor for performing a common key encryption operation; and

frequency control means for changing an operation frequency of the non-contact IC card so that communication with the reader/writer and the encryption operations performed by the encryption means are carried out at different operation frequencies.

2. A non-contact IC card according to claim 1, wherein hardware of the encryption means which is not required for the public key encryption operation is not operated during the public key encryption operation, and hardware of the encryption means which is not required for the common key encryption operation is not operated during the common key encryption operation.

3. A non-contact IC card according to claim 1, wherein a hardware unit having an identical function is shared between the public key encryption processor and the common key encryption processor, and the shared hardware unit is switched in a time-shared manner according to the operation mode.

4. A non-contact IC card according to claim 1, wherein a clock gear is used to change the operation frequency.

5. A non-contact IC card according to claim 1, wherein a frequency divider is used to change the operation frequency.

6. A non-contact IC card according to claim 1, wherein the duty factor of an enable signal is controlled to change the operation frequency.

7. A non-contact IC card according to claim 1, wherein the operation frequency is changed based on a control signal from the reader/writer.