Patent Publication Number: US-6704715-B1

Title: Method and system for ensuring the security of the remote supply of services of financial institutions

Description:
The domain of this invention is remote services offered by financial organizations such as banks and/or insurance companies to their customers. 
     More precisely, the invention relates to a method and a system enabling customers of a bank or an insurance company to securely and quickly access services offered by the said bank or insurance company to its customers, from a remote location using a microphone connected to a communications network. 
     The problem that arises is to prevent a dishonest user from accessing the services offered by the bank or insurance company without being authorized to do so, without paying the corresponding costs, or from claiming that he did not request the services that were debited to him. 
     To solve this problem it has been proposed to use access keys generated by the customer using peripheral equipment. Apart from their costs, these solutions are not very practical and take a long time to set up. The problem that arises can only really be solved if a solution is known to another problem—how to design a method and system that is convenient to use and that can be quickly and economically installed. Ease of use and time savings are major problems for any product aimed at the general public, and cannot be ignored. 
     In other domains, such as telephone subscriber cards (document CA 2 085 775 in the name of Michel BOURRE), telephone games (document FR 2 702 181 in the name of Lucas GORETA), and telephone number dialers (document WO 96 04741 in the name of Andrew MARK), it has been proposed to use a card emitting DTMF type encrypted acoustic signals. Thus, the holder of a card of this type can couple it to the microphone in the telephone handset to automatically transfer his identifiers to the computer services. Since these identifiers are encrypted, it may be thought that a third party will be incapable of understanding the contents. However, there is nothing to stop the signals emitted by the card from being recorded, and a defrauder in possession of this type of recording could substitute himself for the card holder. 
     Therefore the solutions proposed by M. BOURRE, L. GORETA and A. MARK, transposed to remote services offered by financial organizations, would not prevent a dishonest user from accessing services offered by the bank or insurance company without authorization. 
     Patent application DE,A,43 25 459 deposited by Raymond H. EILESE describes a calculator that emits acoustic identification signals that vary in each operation. Therefore, there is no point in a defrauder recording this type of acoustic signal. However, its large size, the fact that it is cumbersome and inconvenient to use and its high cost price prevent it from satisfying the objectives of this invention, namely to design a method and a system that are convenient to use and can be quickly and economically installed. In fact, a customer of a bank or an insurance company will not call upon the services of the said bank or the said insurance company unless access is fast and easy. 
     The objectives of this invention are achieved, and the problems that arise with techniques according to prior art are solved according to the invention by means of a method comprising the following steps: 
     the bank or insurance company provides each of its customers with a card, the same size as a credit card, customized by identifiers specific to each card and to each customer, 
     the said card emits short acoustic DTMF type identification signals, at least partly encrypted and varying for each operation, when the customer of the bank or insurance company ( 12 ) uses it, 
     the said acoustic signals are received by the microphone and are transmitted through the communications network to the bank or insurance company&#39;s computer service, 
     the transmitted signals and the customer and card identification data stored by the computer service are processed and electronically compared by the bank or insurance company&#39;s computer service. 
     Thus with this method, the bank or insurance company can verify that the caller actually has an authentic card and not a computer artifice. He can also identify the card holder as being a person authorized to use the offered services. Consequently if the results are conform, the customer is immediately put into contact with the voice server of the bank or insurance company. Furthermore, defrauders cannot determine identification data since they were automatically transmitted in encrypted form. Furthermore, with the recorded acoustic signals in any form whatsoever, a defrauder will be unable to identify himself to the bank or insurance company&#39;s computer services and benefit from their services. The acoustic identification signals are different for each operation, in other words every time that the card is used. 
     It is noted that, as the term is employed in this specification, the emission of acoustic signals by the card is considered to be “use” of the card. Thus, when it is stated herein for example that the acoustic signals are different every time the card is used, it is to be understood that the acoustic signals are different each time they are emitted. 
     Preferably the said card: 
     also counts the number of times C(p,n) that it is used, 
     emits acoustic signals representing the number of times C(p,n) that it has been used, 
     encrypts acoustic signals as a function of the number of times C(p,n) that it has been used. 
     Also preferably, the said computer means for processing and electronically comparing the transmitted signals and the customer and card identification data held by the bank or insurance company&#39;s computer service, 
     store the number of times C(p,m) that the card has been used at the time of the last validated operation, 
     compare the number of times C(p,n) that the card has been used at the time of the current operation, with the memorized number of times N 1 , 
     refuse the current operation if C(p,n) is less than or equal to C(p,m) and continue verifying the current operation if C(p,n) is greater than C(p,m), 
     recalculate electronic signals S′ (p,n) as a function of identification data and the number of times C(p,n) that the card was used, during the current operation, and then compare them with the transmitted electronic signals S (p,n). If the values agree, the customer may then immediately be connected to the voice server of the bank or insurance company. 
     Note that the use of a microcircuit to encrypt, by means of a counter, identification codes exchanged between an emitter and a receiver was described in patent application EP 0 459 781 A1 deposited in the name of NANOTEK LIMITED. 
     In order to increase security, in one variant embodiment, the method also comprises a step in which the customer uses a keypad associated with the microphone and/or the card to send a pin code. After transmission to the bank or insurance company&#39;s computer service through the communications network, this pin code is processed and compared with the customer&#39;s pin code held by the bank or insurance company&#39;s computer service. 
     Thus the bank or insurance company can check that the caller is actually the person authorized to be connected to their services. A stolen card cannot be used by the thief, since he does not know the pin code. 
     In another variant embodiment also designed to increase security of the method and to make it impossible for the customer to dispute the order that he made to the bank or insurance company, the method also includes the following steps: 
     orders given by the customer to the bank or insurance company are validated by the customer by using the card so that it sends an encrypted acoustic validation signal, 
     the computer service records the said validation signal. 
     Advantageously, an acknowledgment is sent to the customer. 
     With this method, the customer used an electronic signature to validate the order that he gave to the bank or insurance company. 
     The invention also relates to a system enabling customers to a bank or insurance company to quickly and reliably access services offered by the said bank or the said insurance company to their customers. This system is capable of understanding the means of implementing the method described above and its variant embodiments. 
     More particularly: 
     The system according to the invention comprises a card, the same size as a credit card, customized by specific identifiers for each card and for each customer, provided by the bank or insurance company. The card comprises means of emitting short acoustic identification signals of the DTMF type. These acoustic signals are emitted when the customer of the bank or insurance company controls the emission means using an element accessible from the outside of the card. The card also comprises encryption means in order to encrypt at least part of the acoustic signals, and to vary them whenever the card is used. 
     The system according to the invention comprises a telephone handset comprising a microphone used to receive acoustic signals, and to transform them into electrical signals that can be transmitted through the communications network. 
     The system according to the invention also comprises computer means dependent on the bank or insurance company&#39;s computer services connected to the communications network and remote from acoustic signal emission means. The said computer means comprise: 
     a database containing the references of the cards and customers and their identification data, 
     processing means and means of comparing the electronic signals and identification data contained in the database. 
     Thus with this system, the bank or insurance company can verify that the caller has actually an authentic card and not a computer artifice. Furthermore, the bank or insurance company can also identify the card holder as a person authorized to use the services that they offer. Consequently if the card is conform, the customer will immediately be connected to the server or the bank or insurance company. Furthermore, a defrauder will not be able to identify himself to the bank or insurance company&#39;s computer services using a recording of the acoustic signals in any form whatsoever, since the acoustic identification signals vary during each operation, in other words every time that the card is used. 
     Preferably, the card also includes: 
     an incremental counter interconnected to emission means and encryption means that is incremented by at least one unit every time that the card is used. 
     Consequently, the state of the incremental counter is sent to the computer means and acoustic signals are encrypted as a function of the state of the incremental counter. 
     Preferably, the said computer means also comprise: 
     means of memorizing the state C(p,m) of the incremental counter at the time of the last validated operation, 
     means for comparing the state C(p,n) of the incremental counter emitted during the current operation with the state C(p,m) of the memorized incremental counter. 
     Consequently, the check on the current operation is refused if C(p,n) is less than or equal to C(p,m) and is continued if C(p,n) is greater than C(p,m). 
     Also preferably, the said processing means and the said means of comparison of the electronic signals and identification data contained in the database include means of recalculating the electronic signals as a function of the state C(p,n) of the incremental counter and the identification data, and then comparing them with the transmitted electronic signals. Consequently if agreement is found, the customer can immediately start communications with the voice server of the bank or insurance company. 
     In one variant embodiment designed to increase the security of the system, the system also comprises second means of comparing a customer&#39;s pin code stored in the database, with a pin code input by the customer. This code is emitted by means of a keypad associated with the telephone handset and/or the card, and is transmitted to the bank or insurance company&#39;s computer means, through the communications network. 
     Thus, the bank or insurance company can verify that the caller is actually the person authorized to access their services. A thief cannot use a stolen card because he does not known the pin code. 
     In another variant embodiment, also designed to increase the security of the system and to make it impossible for the customer to dispute an order that he gave to the bank or insurance company, the system is such that: 
     when the customer activates the said card, it emits an encrypted acoustic signal to validate orders given by the customer, 
     the said computer means include means of detecting and recording the validation signal. 
     With this system, the customer validated the order that he made to the bank or insurance company with an electronic signature. 
     Advantageously, in this case the computer means also include means of printing an acknowledgment of orders made, addressed to the customer. 
    
    
     Other characteristics and advantages of the invention will become clear by reading the description of variant embodiments of the invention given for guidance and in no way restrictive, and: 
     FIG. 1 showing a perspective diagrammatic view of the system and method according to the invention, 
     FIG. 2 showing the card in the form of a block diagram, 
     FIG. 3 showing the algorithm used to verify the authenticity of the transmitted signal. 
    
    
     The system and method according to the invention enable the customer  11 , using a telephone handset  16  comprising a microphone  17  to quickly and reliably access services  17  offered by the bank or insurance company  12  to their customers. The telephone handset  16 , remote from the service provider  12  computer services  18  is connected to the computer services  18  through a communications network  15 . The system comprises a card  10 , substantially the same size as a credit card in terms of length and width, but not necessarily in terms of thickness, the card being customized by specific identifiers for each card and for each customer I 1 . This card is provided to customers  11  by the bank or insurance company  12 . The card  10  comprises emission means, particularly a loudspeaker  13  emitting short DTMF type acoustic identification signals  20 . These signals are emitted when the customer uses a button  14  accessible from the outside of the card (not shown in FIG. 1 since it is on the other side of the card) to activate emission means  13  and the devices controlling them. These emission means  13  are excited by a DTMF signal generator  99  controlled by a microprocessor  104  powered by a battery  106  and controlled by a resonator  107 . The microprocessor  104  contained in the card comprises encryption means  103  used to at least partly encrypt a request for services  17  offered by the bank or insurance company  12  that is to be transmitted from the emission means  13  in the form of acoustic signals  20 , comprising an encryption algorithm  108  and specific identifiers  109  for each card  10  and for each customer  11 , and particularly the secret key  250  used by the encryption algorithm  108 . 
     The acoustic signals  20  are received by the microphone  17  on the telephone handset, against which the customer presses card  10 . The system also comprises transmission means  19  for sending acoustic signals  20  located in the telephone handset  16 . These transmission means  19  send acoustic signals to the remote site after processing, and conversion into electronic signals through the communications network  15 . 
     The system also comprises computer means  21  dependent on the bank or insurance company&#39;s computer services  18 . These computer means are connected to the communications network  15  and are remote from the telephone handsets  16 . 
     These computer means  21  themselves comprise: 
     a database  23  containing the references of the cards and customers and their identification data; 
     processing means  24  and comparison means  25  for comparing electronic signals and identification data contained in the database. 
     Consequently, if the request is conform, the bank or insurance company&#39;s services  30  are immediately accessible to the customer  11 . 
     Preferably, the microprocessor  104  and the encryption means  103  are designed such that the acoustic signal  20  varies with each operation. Encrypting an identification code means transforming it into a series of items of information which are incomprehensible individually and can only be decrypted by the person holding the encryption key. But this can in no way prevent, a copy being made of the encrypted identification code either during its acoustic transmission (recorder) or by the pirating from telephone line. If this copy is improperly used by a defrauder, the receiving system will treat it as having all the characteristics of the original, and it will then be interpreted in order to verify the identifiers of the card. 
     Therefore the problem that arises is how can any reproduction attempt be made impossible? The following describes several variant embodiments to the general means that is used to make a distinction between the original and the copy when analyzing the encrypted signal received by the computer means  21 , by inserting a distinctive element in the DTMF type signal  20  emitted by the card  10 . 
     One of the variants consists of using a “time-dating” function (for example as described in U.S. Pat. No. 4,998,279). This time-dating function uses the “time” parameter that changes continuously. Thus the “copy” is delayed when it is emitted. This type of solution requires that the emission means  13  and the computer means  21  are synchronized. In order to do this, both must have a “time base” and “frequency standard”. These two time bases have their own precision and their own drift. The result is that they slowly but gradually become desynchronized. In order to overcome this technical difficulty, a certain amount of drift is tolerated between the time bases of the emission means  13  and the computer means  21 . As this drift increases, the uncertainty about the “validity” of the information received and the risk of fraud also increases. Thus, if a drift of one minute is tolerated, the analysis system in the computer means  21  will consider that an illegal copy of the encrypted signal emission is valid if it is reused fraudulently within the next 30 seconds. 
     Another variant consists of using incremental lists (for example as described in U.S. Pat. No. 4,928,098). The emission device and the reception device have an ordered list of the successive encryptions of the identification code, or have algorithms that can be used to prepare them as time goes on. At a given instant, computer means  21  are waiting for the encrypted result C(n). If they actually receive the message C(n), it validates the operation. But the computer means  21  may receive a different message, the card user may have activated the card&#39;s emission means  13  several times, possibly by playing with it or perhaps accidentally, so that the card is in the situation that it emits the encrypted result C(n+p) the next time that it is used with the computer means  21 . If the computer means  21  receive a different message, they will search forwards in the list of successive encrypted results to see if there was a message C(n+p) identical to the received message. One way of removing the ambiguity between “is this an authentic message emitted by the emitter?” or “is it a fraudulent message?” is to request the next emission, or wait for it. If the next emission is identical to C(n+p+1), the system validates the message and puts itself in waiting for the next emission in state C(n+p+2). If it is different, the message is not validated and the analysis system remains in waiting for message C(n). This variant embodiment is not very ergonomic since it obliges the card holder to activate the card several times. 
     According to one preferred variant embodiment for distinguishing the original signal from its copy, the onboard microprocessor  104  in card  10  comprises an incremental counter  105 . The incremental counter  105  is incremented by one or several units each time the card is used. Obviously, like a ratchet, it cannot go backwards, and simply move forwards every time it is used. 
     In the case of this variant embodiment, the state C(p,n)  242  of the counter  105  is used in the calculation of the encrypted message  244  sent by emission means  13 . The algorithm  108  (for which the equivalent algorithm  247  is memorized in the computer means  21 ) calculates the encoded part S(p,n)  241 , using the secret key  250  specific to each card and the state C(p,n)  242  of the counter  105 . In addition to the identification number I(p)  240  of the card and the encrypted identification code S(p,n)  241 , the card  10  emits the state C(p,n)  242  of its incremental counter  105  during each emission. The computer means  21  memorize  230  the state C(p,n)  242  of the incremental counter  105  during the last validated operation, in the database  23 . Thus each time a message  244  is received, the comparison means  25  in the computer means  21  can compare  245  the information received about the state C(p,n)  242  of the counter  105 , with the previous information received C(p,m)  246  stored in memory  230 ,  23 . 
     a) If the state C(p,n)  242  of the counter  105  (FIG. 2) expressed in message  244  is greater than the previously received state C(p,m)  246  (n&gt;m), then the message  244  is accepted and the analysis continues. 
     b) If the state C(p,n)  242  of the counter  105  expressed in message  244  is less than or equal to the previously received state C(p,m)  246  (n&lt;m), then the message will be refused. The received message can only be a copy made previously or a computer artifice. 
     If the conditions described in item a) above are satisfied, the computer means  21  can be used to read the fixed part I(p)  240  and to search for the corresponding secret key for the card in their own database  23 ,  230 . The calculation means  239  in the processing means  24  may then calculate the encrypted code expected by the computer means  21 , using the algorithm  247 , the state of the counter C(p,n)  242  and the secret key (p)  250 . The comparison means  25  then compare the encrypted code S′(p,n)  248  thus calculated  249  with the encrypted code actually received S(p,n)  241 . Therefore this method and these means can validate or invalidate message  244 , without the need for the card user to activate the card several times as is the case in the variant embodiment described above. 
     The existence of an incremental counter  105  in card  10  can define the maximum number of times that the card can be used when the card is being individually programmed, at no additional cost. Once this maximum has been reached, the card will no longer emit a consistent message and is therefore refused by the computer means  21 . 
     The emitted frame  244  contains the following for a given card (p), 
     a fixed part I(p)  240  (the card identification number), 
     a variable incremental part C(p,n)  242  (the state of the counter), 
     a variable part S(p,n)  241  which is apparently random (the result of an encryption algorithm  108  on the secret key  250  specific to this card (p)). 
     The frame emitted: 
     is always different on each different card, 
     for the same card, is always different on each emission. 
     For a given card (p), the computer means  21  can: 
     read the fixed part I(p)  240  (the card identification number), 
     search in their own database  23  for the secret key  250  of this card and the last record received of the state C(p,m)  246  of the counter  105  on this card, 
     refuse this frame  244  if the state of the counter C(p,n)  242  for the current operation is less than or equal to the previously received state C(p,m)  246 , and continue the verification of the current operation if the state C(p,n)  242  is greater than the previously received state C(p,m)  246 , 
     decrypt the received message  244  and validate its contents, by recalculating the specific key  250  for this card using the encryption algorithm  247  and the state of the counter C(p,n)  242  and then comparing the result of the calculation with the received message. 
     Thus using this combination of means, it is possible to emit DTMF type acoustic identification frequencies using a card the same size as a credit card, the frequencies being received by the microphone in equipment connected to the telephone network and being certain of the authenticity of the calling card and thus eliminate the possibility of any defrauder using a sound or computer record or a computer artifice. Consequently, if the results are conform, customers  11  can immediately access services  30  offered by the bank or insurance company. 
     In order to increase the security of the system in the variant embodiment shown in FIG. 1, the system also comprises second comparison means  26 . These comparison means are used to compare a pin code for the customer contained in the database with the pin code emitted by the user. This code is emitted using a keypad  27  associated with the telephone handset  16  and/or the card  10  and transmitted to the computer means  21  belonging to the service provider through the communications network  15 . 
     Thus, the service provider is assured that the caller  11  is actually the person authorized to get into contact with their services. A thief cannot use a stolen card because he does not known the pin code. 
     In another variant embodiment, also designed to increase the security of the system and to prevent the customer from disputing the order that he gave to the bank or insurance company, the system according to the invention is such that: 
     when the card  10  is activated  14  by the subscriber, it emits an encrypted acoustic signal validating the orders given by the customer  11 , 
     the said computer means  21  comprise means of detecting  21   a  and recording  21   b  the validation signal. 
     The card may emit the validation signal either upon prompting from the bank, automatically without prompting, or without prompting at the customer&#39;s instruction, i.e. by activating the button  14  again. 
     With this system, the customer enters an electronic signature to validate the order that he gave to the telecommunications operator. The validation signal comprises transmission of this electronic signature. 
     Advantageously in this case, the computer means  21  also comprise means  28  of printing an acknowledgment  29  of the given orders. This acknowledgment is addressed to the customer  11 .