EP0982687A1

EP0982687A1 - Method for preventing or detecting fraud in an identification system

Info

Publication number: EP0982687A1
Application number: EP98810845A
Authority: EP
Inventors: Peter A. Dr. Stegmaier
Original assignee: Datamars SA
Current assignee: Datamars SA
Priority date: 1998-08-26
Filing date: 1998-08-26
Publication date: 2000-03-01
Also published as: ES2175917T3; HK1026287A1; EP0982688B1; DE69901589D1; ATE218231T1; DK0982688T3; DE69901589T2; EP0982688A1

Abstract

In an identification system comprising a transponder attached or associated to an object such as an animal and means for reading the identifying code memorised in this transponder, additional information such as a serial number of the chip used in the transponder is memorised and transmitted with the code during reading of the transponder. In this way, fraudulent copying of transponders is prevented and/or detection of such copies improved.

Description

This invention relates to a method according to the preamble of claim 1. Identification systems of this type are well known, for instance from US-patent 2 293 399. The objects to be identified by such systems may be of any kind, but they often are animals, for instance as described in US-patent 5 211 129. No specific means are disclosed in the patent specifications mentioned above for preventing or at least detecting fraud by copying transponders wherein the identification code of some valuable object such as an animal is stored.
The transponders usually make use of integrated circuits (chips) as active elements. Of these chips mainly three versions exist:

the laser programmed on wafer level. These chips can be looked at as invariant.
the OTP versions (one time programmable). These chips are programmed sometimes before being put into the object to be identified.
the read/write versions. These chips can, at least partially, be reprogrammed at any time.

Fraud by copying the code of a specific transponder into an OTP transponder in order to obtain two identical transponders can occur and needs to be made impossible. One well known approach is to use a secret key and some cryptographic algorithm (symmetric or asymmetric) to generate a cyphrate out of a random number sent to the transponder as challenge. The cryphrate is sent back from the transponders to the reader.. Often the code of the transponder is also used as input to the cryptographic algorithm. Knowing algorithm and secret key (or public key in asymmetric systems) the reader can authenticate the transponder at any time. This method, however needs to make use of at least one secret key and therefore requires sophisticated key handling.
This invention aims in providing security against copying without reaching the level of cryptography. This security is obtained by the characterising features of claim 1.
The advantage of this method is that it is not requiring complicated and error prone key handling and requires almost no computing power. The latter in contrast to cryptographic methods. Preferably, the method makes use of a chip serial number that makes the combination of the code and the chip serial number almost unique as long as the respective chip manufacturer never produces two identical serial numbers. By registering code and serial number on a certificate that holds the data of the object to be identified and is kept separate from the object a simple copy operation into readily available OTP transponders becomes impossible.
However, to make sure that attempting fraud using chips with programmable serial numbers is recognised, a database can be used either at identification set-up time when the code/serial number pair is stored into the database or at code read time. At both moments the databasecan be searched for double serial numbers and/or codes.
To avoid the need for reading long serial numbers a checksum (e.g. CRC) can be generated from the serial number and used for the above mechanism instead of the serial number. This however may reduce security.
To make the serial number even more specific, a chip manufacturer identification (ID) may also be associated to the chip and made part of the serial number using the above method.
This identification of the manufacturer or the user of the chip may be a trademark such as the registered trademark RID of applicant.
With every code read the respective time information, a geographic information etc. can be stored into the database to facilitate plausibility checks. Other and additional information may be stored in the memory of the transponder. A possible method is described below, whereby additional information mentioned therein may be omitted or replaced by other specific information.

Detailed description of the Method based on the example of ISO 11 784/85 transponders:

At die production time a unique die serial number and a die manufacturer identification (ID) are attributed to every die.
At code programming time the code, the die serial number, and the die manufacturer-ID are combined into a consistency check number using a standardised method, e.g. a CRC scheme. The resulting number is programmed into the trailer bits and needs to be stored in the respective database, marked down in the animals passport, etc. for subsequent consistency check.
At code read time the code, the die serial number, the die manufacturer-ID, and the trailer bits are read and the same method is applied to check consistency of all four numbers.
Then comparing the trailer bits (i.e. the number stored therein) with the respective number in the database in the animals passport etc. the tag (transponder) can be authenticated.
This method can prevent from copying transponders as long as no OTP dies are available that allow the programming of die serial number and die manufacturer-ID at code programming time.
By storing of the respective information into a database with access limited to authorised personnel the copying of serial numbers can be detected.

Claims

A method for preventing or detecting fraud in an identification system wherein a transponder having a memory comprising an identifying code is associated with an object to be identified, such as a valuable animal, this transponder being activated by an interrogating signal for transmission of said code, the so received code being used through registration of the code along with object informations for identification of said object, characterised in that at least one additional information is memorized in said memory and registered, authentication of identification of said object being based onto the combination of said code and said additional information by comparison with said registered code and registered additional information.
The method of claim 1, wherein said additional information is a representation of the manufacturers name or trademark.
The method of claim 1 or 2, wherein said additional information is memorised during manufacture of the transponder chip as a unique chip serial number which cannot be altered by the programmer of the transponder code.
The method of claim 3, comparing the registration at identification set-up time where the code and serial number are registeredfor double serial numbers to discover fraud by using chips which allow or enable programmable serial numbers.
A method according to any one of claims 1-4, comprising integrating a die manufacturer ID into the serial number to avoid double serial numbers from different manufacturers.
A method according to claim 3, comparing using a checksum-type number made out of the serial number to gain time in reading the shorter checksum instead of the serial number.
A method according to claim 6, comprising using a checksum-type number made out of the serial number and a manufacturer identification (ID) to gain time in reading the shorter checksum instead of the serial number and manufacturer ID.
A method according to claim 6 or 7, comprising storing the checksum-type number also into the transponder so that four different information are obtained: code, serial number, manufacturers ID, and checksum, reading all four information at authentication time allowing to check consistency.
A method according to claim 7, wherein the checksum-type number is made out of the serial number, the manufacturer identification (ID), and the code in order to permit a consistency check over code, serial number, ID, and checksum-type number.
A method according to claim 8 or 9, comprising additionally storing code and serial number in a database not accessible by fraudulent personnel.
A method according to claim 10, comprising additionally storing manufacturer ID in a database not accessible by fraudulent personnel for checking for double serial numbers and double manufacturers ID in the database to detect copied die serial numbers and copied manufacturers ID.
A method according to any one of claims 1-11, wherein said code and said additional information are registered in a database or in a certificate not accessible to non-authorised persons or in a computer database with write access only to authorized persons.
A method according to claim 12, making use of time information, geographical information, information on the code-reading person or organisation and so on, gathered during code-read time and making plausibility checks possible in order to detect copies of transponders.