GB2398152A

GB2398152A - A Credit or debit card with a changing card number

Info

Publication number: GB2398152A
Application number: GB0302852A
Authority: GB
Inventors: Stephen Anthony Gerar Chandler
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-02-07
Filing date: 2003-02-07
Publication date: 2004-08-11
Also published as: GB0302852D0

Abstract

The basic invention is a credit or debit card containing an electronic circuit which functions similarly to existing smart cards, but whose card number changes in a random or pseudo-random manner known to the card issuing or account holding institution, after each transaction. An enhanced version incorporates the ability to modify the number according to the amount of the transaction and/or a PIN number, thereby providing further checking and enabling the card to record within itself a reliable record of transactions.

Description

2398 1 52 Credit and debit cards

Introduction

This invention relates to credit and debit cards and devices of similar functionality. s

An increasing number of purchases of goods and services as well as cash withdrawals from Automatic Teller Machines (ATM), are being performed using credit and debit cards. This makes the use of cards a prime target for fraudsters. ATM machines are relatively secure, requiring the use of a Personal Identification Number (PIN) as well as the physical card in order to withdraw money. Fraud by the use of bogus ATM machines, for example, have though, been reported. The use of smart cards containing active electronic circuits should help somewhat. The security of payment for goods in person is enhanced by the requirement for a handwritten signature to confirm the purchase.

However when paying for goods or services by telephone or over the Internet, the only information used is the card number. There is in fact nothing to prevent purchases being debited twice, by mistake or by deliberate fraud, or even totally bogus transactions implemented, once the number has been disclosed. The only protection is provided by the fact that the name of the payee is recorded on the statement. Theoretically this should enable action to be taken, but in reality it would be likely to be too much effort unless the sum involved were large, particularly if the payee is located in another part of the world. It certainly gives no re-assurance to potential users who are unlikely to have any hard evidence of a transaction and certainly not that a transaction did not take place. Of particular concern is the double clicking problem in which the same goods or service can easily be ordered twice. The fact that even some of the largest and well-known names can refuse to refund multiple payments even it is evident that this could not have been intended. An example of this, which stimulated this patent, involved paying for Internet service provision. Although inconceivable that anyone would wish to pay for multiple contract to use the Internet from the same telephone, the ISP, one of the leading names, only agreed to refund the multiple payment when it was proved that the person who performed the multiple click was a minor. The feeling of powerlessness which results from such not uncommon experiences, is probably a major concern restricting the payment for goods over the internet.

Another restriction on the payment of goods over the Internet is that those to whom payments may be made by card are carefully vetted by the credit card companies. Inevitably there is a balance to be struck between security and flexibility of use of credit or debit cards.

On the other hand payment by cheque gives the payee considerable control and security. The cheque number is printed on statements giving a ready means of verifying the validity of a debit. They may also be used for payment of anyone with a bank account, rather than only a certain, though increasing number of trading organizations. The difference is essentially that a cheque can only be used once, whereas a credit card number can be used any number of times without the protection afforded by the direct debit guarantee.

Prior Art

One solution to this problem is provided by the American Express Single Use Card. This would enable a single purchase to be made without revealing a credit card number, which would not be of any use to anyone who intercepts it apart from for the original transaction. This is obviously not convenient for the usual usage of credit or debit cards.

Another solution was for a set of check numbers printed on a scratch card to be used to validate credit card transactions. The trouble with this is that this would be a procedure different to that normally used for credit card transactions and would probably be deprecated by the merchants who would have to modify their software and procedures for what would initially be a minority payment mechanism. The invention disclosed below achieved the same objective without requiring any change of software or procedures from those currently in use. The fact that this idea does not seem to have caught on suggests that the advantages which the method obviously has, are outweighed by the issues mentioned above.

McCown et al in patent WO 02/103642 A2 disclose a method of enhancing security by transmitting a digest of various information, which could include the transaction number. However, it is a change to the process of information exchange between the parties involved which would again require a major change to all e-commerce software as well as being more difficult to use for telephone payments. These are the nearest prior art to the method disclosed of which the author is aware.

The Invention The basic invention is a credit or debit card or device of similar functionality, referred to henceforth as card, containing an electronic circuit which functions similarly to existing smart cards, but whose card number changes in a random or pseudo-random manner known to the card issuing or account holding institution, henceforth for simplicity referred to as the Bank, after each transaction.

An enhanced version incorporates the ability to modify the number according to the amount of the transaction and/or the identity of the payee, thereby providing further checking and enabling the card to record within itself a reliable record of transactions.

Drawings In order that the invention may be more fully understood, reference will now be made, by way of example, to the accompanying drawings, in which: Figure I shows a card being an embodiment of the invention using connected electronically to the bank computer.

Figure 2 shows the same embodiment connected to a personal docking station as it would be used to make a purchase by telephone or the internet.

Figure 3 shows a card being an embodiment with enhanced functionality

Detailed Description

Memory technology is now such that there would be no problem in storing enough card numbers to last the lifetime of a physical card. If the level of use were such that the numbers in a card were to be about to run out, this would be known to the Bank which could easily issue a new card in the normal manner.

Electronic re-charging at an ATM machine for example, though straightforward to implement, would probably be unnecessary. 1 his number would be accesses in the normal manner for smart cards using electrical connection for ATM transactions or customer present purchases from merchants with the appropriate technology. However, for telephone or Internet applications the number could be read by placing it in the customer's own docking station, being a low cost device designed for the purpose, which would probably have the appearance of a calculator. In another embodiment the card could be made with an LCD display for the card number and means for entering the conclusion of transactions.

The advantage of the latter would be convenience of use, whereas the former has the advantage of a lower cost card and increased functionality as, for example, the enhanced version below.

Credit, or debit card numbers contain the identity of the Bank, the identity of the account, and check digits to ensure that the probability of a random number with the right number of digits being a valid card number is sufficiently small. For example four decimal check digits would give a probability of a random choice being correct as 0.0001. The fact that this information is subject to a mapping process to produce the actual number on the card does not affect this structure.

In the invention described above, random or pseudo random check digit combinations are used by the Bank to generate an ordered list of card numbers referring to a particular account which are stored or, with less security, re-generated as an identical list, on the card itself.

The changeable card number would only be used for situations in which the payee has on-line connection to the account holding institution, which would use the members of the list in sequence for successive payments. Memory technology is now such that there would be no problem in storing enough card numbers to last the expected lifetime of a physical card. If the numbers in a card were to be about to run out, this would be known to the Bank which could easily issue a new card in the normal manner. Electronic re-charging of the card with new numbers at an ATM machine for example, though straightforward to implement, would probably be unnecessary. For ATM transactions or customer present purchases from merchants with the appropriate technology providing electrical connection to the eard, this number would be transferred in the normal manner for such smart cards. This is illustrated in Figure 1, where the eard 1 comprises a memory means 2 containing the list of card numbers, a microcontroller or electronic control and interfacing logic 3, and a nonvolatile counter 4.5 represents means by which the eard is electronically connected to the bank computer or database containing 6 which holds the bank's copy of the same data as in 2 which it references using its copy 14 of the current transaction number which should be the same as held in 4. Arrows indicate the directions signals or information may be passed. The card would probably be powered from 5 rather than contain its own power source.

When the numbers are entered into 2, the list in 7 would be copied into 2 in an appropriately secure manner. Once this is done the design of 2, 3 and 4 is such that numbers may only be read out once and In sequence.

However for telephone or Internet applications the number could be read by the card holder either by placing it in a docking station, being a low cost device designed for the purpose, which would probably have the appearance of a calculator. This is illustrated in Figure 2 in which the card is connected to a docking station 8, containing a display device 9, together with a key or other means 10 of signalling the start and completion of a transaction to the eard. Dashed arrows between and the merchant's terminal device 11 indicate that communication involves the card owner reading the number displayed by 9 and forwarding this information verbally or by keying it into a website, and conveying the completion of the transaction using 10.

In another embodiment, the card itself could be made with an LCD display for the card number and means for entering the conclusion of transactions. The advantage of the latter would be convenience of use, whereas the former has the advantage of a lower cost eard and increased functionality as, for example, the enhanced version below.

When a payment has been made, the eard must be informed by some means so that it uses the next number for the next transaction. This could be most easily implemented by incrementing a counter in non-volatile memory pointing to successive entries in the number list. Ensuring that this is done is straightforward when the eard is connected electronically to a card reading machine, but is more difficult where the eard is read from a display manually. The docking station approach makes it easier to ensure this, by requiring the user to answer whether a transaction has taken place or not before the card can be removed. However since the payee would be aware of the problem in attempting to clear the transaction, the eard user would be prompted to tell his card of a previous transaction if that had been omitted. The card would then output the next number which would be accepted. It is also possible that the user could inadvertently manually tell his card of the same transaction twice. This would mean the card would effectively use the next-but-one check digit combination in place of the correct one.

This would be rejected by the bank, and the customer would then try again with the next number. The probability that two successive random choices of check digits would be those of the two next entries in the list is the square of the probability of guessing a correct card number, and there is therefore a negligible degradation of security in making the bank accept and act upon the premise that the counter 4 had got out of step. The process of declining invalid transaction attempts therefore provides a means of re-synchronising 13 with 4.

In an alternative, but deprecated variant on the technique, the number could depend on the time of the transaction rather than the transaction count. This would make resynchronisation of the card with the bank information easier so long as the clock used by the card could be guaranteed to be sufficiently accurate, and the time period between successive number changes sufficiently large for timing skew between the request for the number being made to the card and the actual transaction time to be small.

This would though have the effect of reducing the protection against double entry errors or fraud. It would also be susceptible to someone with knowledge of the dependence of eard entries on time presenting a fraudulent payment request at a time they knew the same number would be used as they had overheard. These issues, together with the technical problems of providing and powering a clock on the card, make this approach unsuitable.

The variable numbering system would obviously not be compatible with older technology using embossed digits or magnetic strip readers, though the latter usually have the facility for manual entry which obviously could be used. However these are only applicable to customer present transactions which are not the concern of the invention. However there is no reason that the same card could be used, but with a different, fixed, card number for use in such transactions. The account holding institution could then refuse to accept these numbers for customer absent transactions.

An enhancement of the basic form of the invention, as illustrated in Figure 3, is to modify the card number by some one to one mapping according to some algebraic function of either or both of the value of the transaction and a PIN number. This would have a number of advantages, one being for the cardholder to ensure that the correct amount is debited, another being to enhance security in the case of theft of the card. This would require the credit card to be told the amount of the transaction and/or the PIN number before it would generate the variable card number. This would almost certainly require the use of the docking station approach. Payment in different currencies would pose difficulties, though these are not insurmountable.

Confirmation of such a transaction would ensure that the correct payment had been debited, but also that the correct data had been entered into the card. This would enable the card, if provided with non volatile memory 13 such as Flash, to be used to hold a reliable record of the transaction information, which could be used to check statements of account, and would provide reliable evidence of fraud or error. In this respect it would be much better than a cheque book.

In short, the device disclosed would not only provide greater security against fraud but also give much greater confidence to those who increasingly require to disclose their credit card or debit card numbers in customer absent transactions, and thereby assist the growth of ebusiness.

Claims

Claims 1. A credit or debit card or device of similar functionality

containing a means to supply an identification number which changes from transaction to transaction in a manner which the bank or S other card issuing or account holding institution or information network serving it may interpret correctly using information held by or available to them and used to validate a single transaction.
2.A device as in claim I wherein the numbers supplied by the card are selected in turn from an ordered list known to the card issuing or account holding institution or information network serving it.
3.A device according to claim I or 2 wherein the current positions in the list held in the card and that held by the account holding or transaction networking database may be synchronized by means of feedback provided by the rejection of transaction attempts.
4.A device according to any previous claim wherein the card numbers are modified according to the value of the transaction the identity of the payee or a PIN number.
5.A device according to any previous claim wherein the number provided by the device is communicated by electrical signals
6.A device according to any previous claim wherein the number provided by the device is communicated by a person reading from optical display device.
7.A device according to any previous claim containing memory means adapted for the storage of transaction information.
8.A device according to any previous claim wherein the communications sent to and from the device conform to the standards used for existing credit or debit card transactions.
9.A device substantially as herein described above and illustrated in the accompanying drawings