FORM 2
THE PATENT ACT, 1970,
(39 OF 1970)
&
THE PATENTS RULE, 2003
COMPLETE SPECIFICATION
(SEE SECTION 10; RULE 13)
"TRANSPONDER BASED IMMOBILIZER"
MAHINDRA & MAHINDRA LIMITED
AN INDIAN COMPANY,
R&D CENTER, AUTOMOTIVE SECTOR,
89, M.I.D.C, SATPUR,
NASHIK-422 007,
MAHARASHTRA, INDIA.
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES AND ASCERTAINS THE NATURE OF THIS INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED

FIELD OF THE INVENTION:-
The present invention relates to motor vehicle security system especially an Immobilizer security system, which includes the uniquely identifiable transponder placed in the key, uniquely identifiable Immobilizer Electronic control unit which identifies the validity of the key based on mutual authentication between the transponder key the immobilizer ECU and securely communicates with the engine management system ECU (EMS ECU) which controls the motor of the vehicle.
BACKGROUND AND PRIOR ART SEARCH:-
In the existing Transponder based Immobilizer system, the transponder is matched with the receiver system which identifies the valid key. The Inquiry/response between the engine management system and Immobilizer ECU is conducted based on the pre-defined code information stored in both the keys. But if the code information is revealed, matching of the control units can be possible which could be potential theft threat. To overcome this, the inquiry/response communication between the control units also depends upon the histories of code generated during the inquiry/response communication hence even if the code information are revealed, the system remain coupled and no other control units can not be coupled with already paired units.
Only part of the system is done with mutual authentication, not all the components involved in the system which leaves some opportunity to iterate around the system and in case of availability of the critical information, this can be exploited. The proposed system which performs the mutual authentication among all the components involved.
Electronically coded transponders are available in the market which can be purchased and the same can be attempted to pair it with the system which is in vehicle. Again this leaves some opportunity to manipulate the system. This will be greatly controlled by restricting the transponder by coding with specific information related to the vehicle family and other specific information which

makes the system to be paired with its meant counterpart hence directly filter outs the possibility of using the same make electronic key available.
All the available systems are avoiding the theft. But no theft avoidance mechanism is discussed. The system explained in this art has the pro activeness to the attempts made in the vehicle and according the restricts itself which even drastically reduces the opportunity of fiddling with the system.
OBJECTS OF THE PRESENT INVENTION:-
The main object of the present invention is to provide transponder based immobilizer for the automotive vehicle.
Another object of the present invention is to achieve the maximum vehicle security level which ensures all possible ways of fiddling with any of the system components.
STATEMENT OF INVENTION:-
Accordingly the invention provides a transponder based immobilizer comprises a portable electronic key transponder chip embedded in the key, a micro-process based Immobilizer unit and micro-process based Engine management system ECU interconnect able by the wireless network When Ignition is ON in the vehicles all these units are interacting with each other in their respective communication medium; the arrangement is such way that the said Immobilizer ECU & transponder in the key are mutually authenticated by both before the key validity information is processed and the said EMS ECU & Immobilizer ECU are mutually authenticated by the both in the before taking the decision on the fuel release.

BRIEF DESCRIPTION OF THE DRAWINGS:-
Fig1: This illustrates about all the components of the Immobilizer and its data as well as its various control modules.
Fig2: This illustrates about all the components of the EMS and its data as well as its various control modules
Fig3: This illustrates about all the components of the transponder key and its data as well as its various control modules.
DETAIL DESCRIPTION AND THE PREFERRED EMBODIMENTS:-
The object is achieved by the system which consists of Electronic key ( A) , Immobilizer ( B) , EMS(C) which each of them communicate with other and the authenticity of the vehicle is arrived. The key(C) communicates with the Immobilizer (B) based on the mutual authentication. The same communication is based on the random numbers generated during this driving cycle and also depends upon the previous communication data which is managed by communication history management(l). Communication history manager (1) works in sync with the communication manager (11 A) so that successful communication possible. Usage of Transponders available from the market is restricted by Transponder restriction module (6) this ensures the usage of the correct transponder keys for particular to vehicle manufactures and the same is customized to inter variants of the vehicle hence strict use of the correct transponder meant for correct vehicle manufacture and correct vehicle variants. The transponder has some of the data which are hard coded data (5) while component manufacturing and it also has the soft coded parameters (6) in it. Which are all going to take part in the mutual authentications which are cryptic using Crypto 2(8). Pro active system (9) which restricts / blocks in case of the unauthorised attempts which eliminates the possibility of understanding and fiddling the system.

The object also comprises of the immobilizer which communicates both the Transponder key and the EMS on mutual communication basis with both the elements and maintains the communication history for both EMS and transponder key.
Proactive system (16) will restrict the operation of the Immobilizer Unit and hence restricts the unauthorised attempts. Immobilizer ECU also has the recovery manager (13) which will ensures the safe and secure handling of the previous ignition cycle data corresponds to transponder. Similarly recovery manager (13A) also takes care about the history data and which history data corresponds to current ignition cycle. This will ensure the synchronisation between the transponder and Immobilizer. This also addresses conditions in which memory can be corrupted with the wrong data, because which the entire authentication will fail. It also has the required fall back mechanism to recover itself in case of extreme conditions.
Immobilizer ECU will also has the soft coded parameters which are coded while manufacturing of the component and it also has the soft coded parameters which are all getting coded once all these components are all getting assembled and paired.
All the data involved in the whole system from all the components are stored and maintained in a non-volatile memory. All the communication between all the components are time scheduled with event triggered nature. The same is controlled by the time control (18), (7), (37). In case of fluctuating power supplies and during interruption of communication, the correct history record will be maintained and successful authentication is realised.
The immobilizer is also controls the power assists and warning systems depend upon the authorisation. Key authentication module will take care all the communication strategy with the transponder. Similarly the vehicle security authentication module completes all the interaction with the EMS and controlling the starter and power assist if applicable and the warning systems. EMS communicates with Immobilizer and based the status of the

communication and the authenticity of the key and immobilizer motor of the vehicles is controlled. In case of failed authentication or communication failures or any other theft attempts the system will immobilize the motor.
A vehicle consists of the EMS ECU(C) and Immobilizer (B) and the transponder key (A). Fig 1, fig 2, and fig 3 these figures are just illustrative and for discussion purposes only. This is not the limit of the literature, the skilled one in the art can realise the same fact in some other way.
The immobilizer
The immobilizer comprises a first vehicle security authentication module communicating with the pro-active system module(16), a first crypto module(17) ,time control module(18), a first communication manager module(12), a first communication history module(12), a first recovery mechanism module(13), a first soft coded parameter module(14), a first hard coded parameter module(15), power assist control module(19), warning system module(20), and a key authentication modu!e(22) communicating with second history manager module(25), a second crypto module(26), key communication module(28), a key restriction module(27), a second hard coded module(23), and second soft coded module(24).
Engine management system
An engine management system comprises a second vehicle security authentication module(33) communicating with a second communication manager(29), a second communication history manager(29), a second proactive system module(35), a third crypto module(36), a second timing control module(37), a second recovery mechanism module(30), a third soft coded module(31), a third hard coded module(32), and a motor actuator module(34).

An electronic key
An electronic key comprises a key control module communicating with a third communication manager(1), a third communication history manager(2), a third pro-active system module(9), a fourth crypto module(8), a third timing control manager(7), a third recovery mechanism module(3), a third soft coded parameters module(4), a third hard coded parameters module(5), and transponder restriction module(6).
Given this specification skilled in the art can realise EMS (C) and Immobilizer by using the single micro controller with all custom software developed.
A portable electronic key can be transponder which is embedded in the key. This will communicate to the Immobilizer ECU by wireless means. The entire electronic key is configured to particular set of Immobilizer Units. This can be realised the keeping the pre fixed crypto key. The same can be written in to transponder one time writable and the reading of the same is locked. So only valid key written transponder are allowed to pair to the Immobilizer hence realising the restriction of transponder which are not meant for this manufacture and this vehicle variant.
The communication between the transponder and Immobilizer is cryptic and the is also based on the histories of the communication between these two units. The random used which are generated during the current ignition cycle along with data used in the last authentication passed which corresponds to previous histories of ignition cycle are used to validate the authenticate the transponder in this cycle. In case of the successful authentication then the data used in this cycle are used in the next ignition cycle. The histories are handled to maintain by communication history manager and these transponder and Immobilizer units are kept under synchronisation. This may not be a random number it can any rolling parameter which is used in the operation of transponder and the immobilizer.

As explained above once the system paired, the any of the system component can not be paired with the any other system components. Immobilizer shall control the power assist based on the successful/unsuccessful status of the authentication. Immobilizer will control the warning/alarm and like systems.
Proactive system (9), (35), (6) are in place to avoid the theft attempt in the vehicle. These are can be realised by custom software. This is not the limit, but this fact can be realised in many ways by those who skilled in the art. All those implements will be an embodiment of this invention.
The communication between the immobilizer and the EMS can be any mode of communication, through which the authentication is performed. The communication between the EMS and immobilizer are cryptic and authentication is based on the history. In every ignition one of the input to authepticate each other unit is the parameter by which both the units were getting authenticated in the previous ignition cycle. The authentication between the Immobilizer and EMS ECU also mutual Immobilizer will respond to the correct EMS and EMS will listen the communication from the correct Immobilizer unit.
The ECU shall maintain the histories of communication to keep the both the units in synchronisation.
The communication between the EMS and immobilizer is restricted with the maximum allowed time. This time scheduled periodically to perform the event triggered communication between the immobilizer and EMS.
EMS shall control the motor of the vehicle in order to allow the vehicle to run. In case of un-successful authentication/ no authentication of any one of the authentications the vehicle will be immobilized and will not be allowed to run. The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed embodiment may become apparent to those skilled in the art that do not necessarily depart from the

purview and sprit of this invention. Accordingly the following claims must be studied to determine the scope of legal afforded this invention.
ADVANTAGES OF PRESENT INVENTION:-
1. Authentication Based on History:
Once Immobilizer ECU & EMS ECU is paired, then no other EMS ECU & Immobilizer ECU can not be paired with the existing pair since the communication between the ECUs' depends upon the histories of the communication.
2. Synchronising the histories:
Present code information belong to the current ignition cycle is house kept with the existing Histories of Immobilizer ECU & EMS ECU to ensure the synchronised history between EMS ECU & Immobilizer ECU.
3. Proactive nature of the System:
The systems will proactively getting immobilised when there is a likely attempt of theft hence prevents the theft attempt. It will automatically recover from this automatically upon the authorised usage.
4. Mutual Authentication:
The immobilizer security system operates based on the mutual authentication between its components.
1. Immobilizer ECU & transponder in the key are mutually authenticated by both before the key validity information is processed.
2. EMS ECU & Immobilizer ECU are mutually authenticated by the both in the before taking the decision on the fuel release.
5. Event communication with controlled time:
The communication between the immobilizer ECU and EMS ECU is event based, with in the restricted time span.

6. Restriction of the Transponder:
All the transponder which are meat for particular vehicle manufacture and particular vehicle variants are configured permanently while assembling the transponder in the mechanical key. So the transponders with out configuration can not be paired and used. Inter and intra exchange of transponders for the vehicles of the same manufacture is blocked. Similar available transponders can not be used.
SUMMARY OF THE INVENTION:-
In general this invention relates to the vehicle security system which consists of the portable electronic key can be transponder chip embedded key and Immobilizer unit and Engine management ECU. When Ignition is ON in the vehicles all these units are interacting with each other in their respective communication medium. Then in case of successful authentication of all these units motor vehicle will be powered to run the vehicle. In case of any un -successful cases vehicle will be immobilized and only made to run in case of the successful authentication cycle after that.
The Key communicates with the transponder with the radio frequency communication. This communication is mutual in the sense the transponder will respond to the only the correct immobilizers for which this has been paired, otherwise no operation of the transponder. Similarly the immobilizer ECU will listen to all the responses from Transponder only when it is meant for it. This communication between the transponder and the Immobilizer is cryptic using all the soft and hard coded parameters. All these communication are also based on the random numbers generated using the ignition cycle but the entire authentication in current ignition depends upon the histories of successful authentication. Histories are carefully house kept to maintain the synchronisation between the transponder and immobilizer.
Immobilizer ECU controls the power assist units may be starter motor of the vehicle. And the immobiliser shall also control the warning systems and the same is getting activated in case of un-authorised attempts.

The transponders are configured specific to the vehicle manufacture and their vehicle variants. Hence only particular transponder meant for particular vehicle manufacture. Immobilizer is provided with the pro active nature , in case if the unit asserts/senses the attempt then the unit will become will inoperative and hence further attempt shall be made vain by the system itself. EMS ECU communicates with the Immobilizer ECU based on the mutual authentication strategy with all the communication between the units are cryptic and based on random numbers. The authentication in the current ignition cycle is based on the random numbers used in previous histories of random cryptic communications. Histories of communication are house kept and the same is handled to ensure the synchronisation between the EMS ECU and the Immobilizer unit.
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The figures shown are all illustrative purposes; actually the whole the EMS and the required behaviours are shown as block diagrams all those functionalities can be realised by using the single microcontroller and with the custom software. Similarly the Immobilizer and the required behaviours are shown as block diagrams all those functionalities can be realised by using the single microcontroller and with the custom software.

WE CLA1M:-
1. A transponder based immobilizer comprises a portable electronic key transponder chip embedded in the key, a micro-process based Immobilizer unit and micro-process based Engine management system ECU interconnect able by the wireless network When Ignition is ON in the vehicles all these units are interacting with each other in their respective communication medium; the arrangement is such way that the said Immobilizer ECU & transponder in the key are mutually authenticated by both before the key validity information is processed and the said EMS ECU & Immobilizer ECU are mutually authenticated by the both in the before taking the decision on the fuel release.
2. A transponder based immobilizer as claimed in claim 1 wherein the said immobilizer comprises a first vehicle security authentication module communicating with the pro-active system module, a first crypto module ,time control module, a first communication manager module, a first communication history module, a first recovery mechanism module, a first soft coded parameter module, a first hard coded parameter module, power assist control module, warning system module, and a key authentication module communicating with second history manager module, a second crypto module, key communication module, a key restriction module, a second hard coded module, and second soft coded module.
3. A transponder based immobilizer as claimed in claims 1 and 2 wherein the said engine management system comprises a second vehicle security authentication module communicating with a second communication manager, a second communication history manager, a second proactive system module, a third crypto module, a second timing control module, a second recovery mechanism module, a third soft coded module, a third hard coded module, and a motor actuator module.

4. A transponder based immobilizer as claimed in claims 1 to 3 wherein the said electronic key comprises a key control module communicating with a third communication manager, a third communication history manager, a third pro-active system module, a fourth crypto module, a third timing control manager, a third recovery mechanism module, a third soft coded parameters module. A third hard coded parameters module, and transponder restriction module.