Security device for a transponder

• US 20050231369A1
• Filed: 04/14/2005
• Published: 10/20/2005
• Est. Priority Date: 04/14/2004
• Status: Active Grant

• Current Assignee: Atmel Germany GmbH (Microchip Technology Incorporated)
• Original Assignee: Atmel Germany GmbH (Microchip Technology Incorporated)
• Inventors: Friedrich, Ulrich, Ziebertz, Dirk
• Granted Patent: US 7,321,300 B2
• Time in Patent Office: Days
• US Class Current: 340/572.100
• CPC Class Codes: G06F 21/31 User authentication
• CPC Class Codes: G06K 19/07345 by activating or deactivating at least a part of the circuit on the record carrier, e.g. ON/OFF switches
• CPC Class Codes: H04L 2209/805 Lightweight hardware, e.g. radio-frequency identification [RFID] or sensor
• CPC Class Codes: H04L 9/3226 using a predetermined code, e.g. password, passphrase or PIN network architectures or network communication protocols for supporting authentication of entities using passwords in a packet data network H04L63/083
• CPC Class Codes: H04L 9/3236 using cryptographic hash functions

Abstract

A security device for a transponder with a kill and/or cloak function is provided. The security device includes a memory device, in which a first, open password is stored, an input, into which a second, secret password is coupled, a cryptologic device, which is connected to the input and generates a checksum from the second password, and a comparison unit, which compares the checksum and the first password and which upon an agreement generates a kill and/or cloak control instruction to activate and/or deactivate a kill and/or cloak mechanism, which can be tapped at an output. A method for configuring a security device and a method for operating a transponder, and a transponder having the security device are also provided.

Claims

1. A security device for a transponder, the security device comprising:

a security function for a kill and/or cloak function;

a memory device, in which a first password is stored;

an input, into which a second password can be coupled;

a cryptologic device, which is connected to the input and generates a checksum from the second password; and

a comparison device, which compares the checksum and the first password and which, upon their agreement, generates a security control instruction to activate and/or deactivate a security mechanism, which can be tapped at an output.

2. The security device according to claim 1, wherein the cryptologic device is a computational device for calculating the checksum.

3. The security device according to claim 1, wherein the cryptologic device is designed as hardware-based device.

4. The security device according to claim 1, wherein the cryptologic device is a linear feedback shift register.

5. The security device according claim 1, wherein the cryptologic device is a CRC register.

6. The security device according to claim 1, wherein the cryptologic device has a plurality of taps through which a signal, which derives the checksum, can be tapped.

7. The security device according to claim 1, wherein a linking device is provided, which is connected to at least one tap of the cryptologic device, witch links together signals provided by the cryptologic device at an output side and generates the checksum therefrom.

8. The security device according to claim 7, wherein the linking device has an AND operation and/or an XOR operation and/or an OR operation and/or a modulo operation.

24. The security device according to claim 1, wherein the security function is a kill and/or cloak control instruction, and wherein the security mechanism is a kill and/or cloak control mechanism instruction.

9. A method for configuring a security device of a transponder, the method comprising the steps of:

storing a first password in a memory device;

inputting a second password into an input;

generating a checksum from the second password by a cryptologic device;

comparing the checksum and the first password; and

generating a security control instruction, on the basis of the comparison of the checksum and the first password, to activate and/or deactivate a security mechanism.

10. The method according to claim 9, wherein, to increase security during the operation of the security device, a bit number of the cryptologic device is increased.

11. The method according to claim 9, wherein, to increase security during operation of the security device, the cryptologic device is repeatedly passed through to derive the checksum.

12. The method according to claim 9, wherein, to increase security during operation of the security device, a number of taps of the cryptologic device is increase, through which a signal is tapped to derive the checksum.

13. The method according to claim 9, wherein, to increase security during operation of the security device, a tap of the cryptologic device, through which a signal is tapped to derive the checksum, is used that is tapped from a flip-flop of an LFSR register of the cryptologic device.

14. The method according to claim 9, wherein a linking device is provided, which links together signals provided by the cryptologic device at an output side and generates the checksum therefrom, and wherein, to increase security during operation of the security device, a number of operation elements and/or a degree of connectivity of the linking device are increased.

15. The method according to claim 9, wherein a central database is provided, in which the second password is stored and from which the second password can be read by additional users who are authorized by an authorized user of the security device.

16. The method according to claim 9, wherein the second password is changed and a changed checksum, which is then stored as a new first password in a memory device, is determined from the changed second password by the cryptologic device and/or a linking device.

17. The method according to claim 16, wherein the second password is changed after a predetermined number of accesses to the security device or after each access to the security device.

18. The method according to claim 16, wherein the second password is changed automatically with the use of a random number.

19. A method for operating a transponder having a security device, the transponder having a first password stored therein, the method comprising the steps of:

transmitting from a base station to the transponder a high-frequency electromagnetic carrier signal;

modulating an information packet onto the high-frequency electromagnetic carrier signal, the information packet having a header section, a middle section, and a terminating end section;

providing a second password at a predetermined position within the information packet; and

operating the security device of the transponder on the basis of a comparison of the first password with a checksum, which is derived from the second password.

20. The method according to claim 19, wherein the middle section has a data field with at least one instruction to be transmitted to the transponder and a security field, which follows the data field, to secure the data transmitted in the data field, and wherein the second password is inserted in the security field.

21. The method according to claim 19, wherein the terminating end section has at least two EOF symbols, which indicate an end of the information packet, and wherein an additional field, in which the second password is inserted, is placed between the two EOF symbols.

22. A transponder for data communication with at least one base station, the transponder comprising:

a transmitting/receiving device for receiving high-frequency carrier signals from a base station;

a control device, which controls the data communication with the base station; and

a security device, the security device comprising;

a memory device, in which a first password is stored;

an input, into which a second password can be coupled;

a cryptologic device, which is connected to the input and generates a checksum from the second password; and

a comparison device, which compares the checksum and the first password and which, upon their agreement, generates a security control instruction to activate and/or deactivate a security mechanism, which can be tapped at an output of the security device.

23. The transponder according to claim 22, wherein a CRC register is provided in the security device for verifying the data transmitted during the data communication between the base station and transponder, wherein the CRC register of the security device is also a CRC register of the transponder.