Techniques for Transaction Adjustment

Abstract

Techniques are provided for transaction adjustment. A payment device, having an offline balance, is presented to an offline terminal in connection with a putative transaction. If an irregularity with the putative transaction is detected, the offline balance is adjusted responsive to the detection. In one aspect of the invention, such adjustment can be carried out, via offline-terminal interaction, substantially without the use of a security module and cryptographic keys in the offline terminal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an exemplary embodiment of a payment system according to an aspect of the present invention;

FIG. 2 presents a flow chart of an exemplary method for transaction adjustment according to another aspect of the present invention;

FIG. 3 shows a flow chart of one possible detailed approach to transaction adjustment, viewed from the card or payment device side;

FIG. 4 shows a flow chart of an approach such as that of FIG. 3, but viewed from the terminal side;

FIG. 5 shows a flow chart of another possible detailed approach to transaction adjustment; and

FIG. 6 is a system block diagram of a computer system having applicability to one or more elements of one or more embodiments of the present invention.

Claims

1. A computer-implemented method for transaction adjustment, comprising the steps of: facilitating presentation of a payment device having an offline balance to an offline terminal in connection with a putative transaction;facilitating detection of an irregularity with said putative transaction; andadjusting said offline balance, responsive to said detection, said adjusting being carried out, via offline-terminal interaction, substantially without the use of a security module and cryptographic keys in said offline terminal.

2. The method of claim 1, father comprising the additional step of receiving, at said payment device, a terminal-transformed number, said terminal-transformed number comprising a substantially unpredictable source number transformed in accordance with a non-invertable transformation scheme, wherein said adjusting step further comprises: receiving, at said payment device, said source number;transforming said source number according to said non-invertable transformation scheme to obtain a payment-device-transformed number; andadjusting said offline balance responsive to said payment-device-transformed number substantially matching said terminal-transformed number.

3. The method of claim 1, further comprising the additional step of dispatching, from said offline terminal, a terminal-transformed number, said terminal-transformed number comprising a substantially unpredictable source number transformed in accordance with a non-invertable transformation scheme, wherein said adjusting step further comprises: dispatching, from said offline terminal, said source number; in a form for subsequent transformation by said payment device.

4. The method of claim 3, further comprising the additional steps of: detecting removal of said device from said terminal prior to said dispatching step; andprompting for re-presentation of said device to said terminal to facilitate performance of said dispatching step.

5. The method of claim 1, wherein; said offline terminal and said payment device are configured to exchange at least an on-line message request and a transaction confirmation request and to complete given transactions with no irregularities by exchanging said on-line message request followed by said transaction confirmation request; andsaid adjusting step comprises refraining from sending said transaction confirmation request in a case when said irregularity has been detected, whereby said putative transaction is not completed.

6. The method of claim 5, further comprising the additional step of physically securing said payment device in said terminal to prevent removal of said device from said terminal prior to sending said transaction confirmation request in a case when no irregularity occurs with said transaction.

7. The method of claim 5, further comprising the additional steps of: detecting a number of instances of a removal of said device from said terminal prior to sending said transaction confirmation request; andblocking said device, responsive to said number of instances being at least equal to a predetermined value.

8. The method of claim 1, further comprising the additional steps of: detecting a number of instances of said putative transactions having said irregularities; andforcing said device to go on-line prior to further transactions, responsive to said number of instances being at least equal to a predetermined value.

9. The method of claim 1, wherein: said offline terminal and said payment device are configured to exchange at least an on-line message request and a transaction confirmation request and to complete given transactions with no irregularities by exchanging said on-line message request followed by said transaction confirmation request; andsaid adjusting step comprises said offline terminal re-crediting said payment device in a case when said irregularity has been detected, said re-crediting comprising said terminal requesting a refusal application authentication cryptogram from said payment device.

10. A computer-implemented method for transaction adjustment, comprising the steps of: facilitating presentation of a payment device having an offline balance to an offline terminal in connection with a putative transaction;receiving, at said payment device, a terminal-transformed number, said terminal-transformed number comprising a substantially unpredictable source number transformed in accordance with a non-invertable transformation scheme;facilitating detection of an irregularity with said putative transaction; andadjusting said offline balance, responsive to said detection, wherein said adjusting step in turn comprises:receiving, at said payment device, said source number;transforming said source number according to said non-invertable transformation scheme to obtain a payment-device-transformed number; andadjusting said offline balance responsive to said payment-device-transformed number substantially matching said terminal-transformed number.

11. A computer-implemented method for transaction adjustment, comprising the steps of: facilitating presentation of a payment device having an offline balance to an offline terminal in connection with a putative transaction;dispatching, from said offline terminal, a terminal-transformed number, said terminal-transformed number comprising a substantially unpredictable source number transformed in accordance with a non-invertable transformation scheme;facilitating detection of an irregularity with said putative transaction;responsive to said detection of said irregularity, dispatching, from said offline terminal, said source number, in a form for subsequent transformation by said payment device.

12. The method of claim 11, further comprising the additional steps of: logging transaction details associated with requests for said dispatching of said source number; andreviewing said details from said logging step to detect merchant-cardholder collusion.

13. The method of claim 11, further comprising the additional steps of: repeating said steps of facilitating presentation, dispatching said terminal-transformed number, and facilitating detection, for a second payment device, said second payment device being incapable of transaction adjustment via said source number; andlogging transaction data associated with said putative transaction with said second payment device, said transaction data comprising a record of a payment associated with said putative transaction and a record indicating that said terminal attempted to adjust said putative transaction with said second payment device.

14. A payment device comprising: a body portion;a memory associated with said body portion and containing an offline balance; andat least one processor associated with said body portion and coupled to said memory, said processor being operative to: receive a terminal-transformed number in connection with a putative transaction, said terminal-transformed number comprising a substantially unpredictable source number transformed in accordance with a non-invertable transformation scheme;receive said source number;transform said source number according to said non-invertable transformation scheme to obtain a payment-device-transformed number; andadjust said offline balance responsive to said payment-device-transformed number substantially matching said terminal-transformed number.

15. A terminal apparatus for interacting with a payment device having an offline balance, said terminal apparatus comprising: a reader module;a memory associated with said reader module; andat least one processor coupled to said memory, said processor being operative to: dispatch a terminal-transformed number, said terminal-transformed number comprising a substantially unpredictable source number transformed in accordance with a non-invertable transformation scheme;detect an irregularity with said putative transaction;dispatch said source number, in a form for subsequent transformation by said payment device, responsive to said detection of said irregularity.

16. A terminal apparatus for interacting with a payment device having an offline balance, said terminal apparatus comprising: a reader module;a memory associated with said reader module; andat least one processor coupled to said memory, said processor being operative to: exchange an on-line message request with said payment device in connection with a putative transaction;exchange a transaction request with said payment device in connection with a successful putative transaction; andrefrain from sending said transaction confirmation request in a case when said putative transaction is irregular, so as to prevent completion of said putative transaction.

17. A payment device comprising: a body portion;a memory associated with said body portion and containing an offline balance; andat least one processor associated with said body portion and coupled to said memory, said processor being operative to: facilitate detection of an irregularity with a putative transaction between said device and an offline terminal, said payment device being configured to exchange at least an on-line message request and a transaction confirmation request with the offline terminal, and to complete given transactions with no irregularities by exchanging, with the offline terminal, said on-line message request followed by said transaction confirmation request; andadjust said offline balance via offline-terminal interaction, responsive to said detection, via the offline terminal re-crediting said payment device by requesting a refusal application authentication cryptogram from said payment device.