Electronic transaction security system and method

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WO 2010/045154

PCT/US2009/060368

TITLE

ELECTRONIC TRANSACTION SECURITY SYSTEM AND METHOD

FIELD OF THE INVENTION

[0001] The present invention relates generally to processing of payment card transactions. More particularly, the present invention relates to a system and method to enhance the security of payment card transactions.

BACKGROUND OF THE INVENTION

[0002] Payment cards, such as credit cards or debit cards, are commonly used to purchase goods and services in person or over the telephone or Internet. The information required to initiate a payment card transaction typically comprises a payment card number, an expiration date for the payment card, and the cardholder’s name. Other information, such as the cardholder’s telephone number and address, may be required. Some or all of the information necessary to effect a payment card transaction may potentially become known to a third party, who may use the information without the knowledge or consent of the cardholder.

SUMMARY OF THE INVENTION

[0003] The present invention recognizes and addresses the foregoing considerations, and others, of prior art construction and methods.

[0004] In this regard, one aspect of the invention provides a computerized method for generating a time-limited number for use in a payment card transaction involving a payment card issued to a user by a financial institution, wherein the payment card i

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WO 2010/045154 PCT/US2009/060368 comprises an original payment card number, the method comprising the steps of providing to a processor a first plurality of digits of the original payment card number, where the first plurality of digits are predetermined digits associated to the financial institution, providing to the processor a desired expiration date through which the timelimited number is valid for acceptance in the payment card transaction, and executing a program by the processor so that the program sets a first plurality of digits in the timelimited number to the first plurality of digits in the original payment card number, generates a first number corresponding to the desired expiration date, sets a second plurality of digits in the time-limited number to the first number, and outputs the timelimited number.

[0005] According to another aspect, the present invention also provides a method for enhancing the security of a payment card transaction involving a payment card number assigned to a user account by a financial institution, the method comprising the steps of generating a time-limited number comprising a first plurality of digits in the time-limited number set to a first plurality of digits in the payment card number associated to the financial institution and a second plurality of digits in the time-limited number set to a first number corresponding to a desired expiration date, where the time-limited number is not associated with the user account, transmitting the time-limited number and data representative of the user account other than the payment card number to the financial institution, locating the user account based on the data, and validating the time-limited number for the transaction based on the digits indicating the expiration date and the data.

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[0006] A further aspect of the present invention provides a system for generating a time- limited number for use in a payment card transaction involving a payment card issued to a user by a financial institution, wherein the payment card comprises an original payment card number, the system comprising a processing device and a medium accessible by the processing device comprising instructions when executed by the processing device cause the processing device to perform the steps of setting a first plurality of digits in the time-limited number to a first plurality of digits in the original payment card number, wherein the first plurality of digits of the original payment card number are predetermined digits associated to the financial institution, generating a first number corresponding to a desired expiration date through which the time-limited number is valid for acceptance in the payment card transaction, setting a second plurality of digits in the time-limited number to the first number, and outputting the timelimited number.

[0007] In another aspect, there is provided a computerized method for identifying an account assigned to a user by a financial institution, wherein the account is assigned a payment card number, comprising the steps of providing to a processing device information corresponding to a payment card transaction associated with the user, where a portion of the information does not include the payment card number and executing a program by the processing device that locates the account based on the portion of the information that does not include the payment card number.

[0008] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more embodiments of the invention and, together with the description, serve to explain the principles of the invention.

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BRIEF DESCRIPTION OF THE DRAWINGS

[0009] A full and enabling disclosure of the present invention, including the best mode thereof directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended drawings, in which:

[0010] Figure 1 is a schematic illustration of a system for effecting a payment card transaction in accordance with an embodiment of the present invention;

[0011] Figure 2 is a flowchart illustrating a method for encoding and decoding information transmitted to a financial Institution in relation to a payment card transaction in accordance with an embodiment of the present invention;

[0012] Figure 3 Is an exemplary graphical user interface of the user device of the system shown in Figure 1; and

[0013] Figures 4, 5, 6, and 7 are flowcharts illustrating methods for encoding and decoding information transmitted to a financial institution in relation to a payment card transaction in accordance with additional embodiments of the present invention.

[0014] Repeat use of reference characters in the present specification and drawings is intended to represent same or analogous features or elements of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0015] Reference will now be made in detail to presently preferred embodiments of the invention, one or more examples of which are illustrated in foe accompanying drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the scope

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WO 2010/045154 PCT/US2009/06036® thereof. For instance, features illustrated or described as part of one embodiment may be used on another embodiment to yield a still further embodiment.

[0016] Generally, a user contacts a financial institution in order to apply for a payment card and provides the institution with information corresponding to the user, such as the user’s name, address, and telephone number. In this sense, a payment card may be a credit cand, a debit card, or any other card or device by which a user may effect a transfer of credit, cash, or other legal tender to a third party. If the financial institution accepts the user's application, the institution issues the user a payment card bearing a payment card number, a card verification code (‘'CVC), and an expiration date. The first six digits of the user's payment card number identify the financial institution that issued the payment card and is referred to as the BIN” portion of the payment card number. The last digit of the payment card number is reserved as a checksum to ensure the other digits of the number constitute a valid payment card number. The remaining digits between the BIN and the checksum are referred to as the personal account number (“PAN”). Normally, the PAN is a 9 or 8-digit number.

[0017] In one preferred embodiment, the financial Institution also supplies a 4-digit private identification number fPIN*) to the user. In one embodiment, the financial institution selects the PIN for the user, while, in another embodiment, the user is permitted to select a desired PIN or may select a desired PIN after being issued an initial PIN by the financial Institution. The user may select a PIN by telephone, through a web site over the Internet, or other communication mechanism with the financial institution. The financial institution stores all the information corresponding to the user and the associated payment cgrd(s) within its corporate system, such as a Secure

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Credit Card Account Data Repository. Once the payment card has been issued to the user, it may then be used to initiate a financial transaction between the user and a merchant.

[0018] Figure 1 illustrates a system 10 for effecting an electronic transaction, such as a payment card transaction. System 10 comprises a user device 12, a server 14 maintained by one or more financial institutions, and one or more computers 16 maintained by at least one merchant. User device 12 may be any device that comprises a processing device 18, medium 20, an input device 22, and a display 24 and may comprise, for example, a personal computer, a laptop or tablet computer, a personal data assistant, a cellular phone, or a multimedia player. Medium 20 may be any medium capable of being accessed by processing device 18, such as random access memory (“RAM”), flash memory, a hard drive, a CD, a DVD, or a combination thereof. Input device 22 may be any device by which a user may supply information to device 12, such as a keyboard, a mouse, or, as shown in Figure 1, a touch screen. In the example shown in Figure 1, touch screen 22 also functions as display 24, but it should be understood that the two may be separate devices. Server 14 comprises its own processing device 26 and medium 28, while computer 16 comprises a processing device 30 and medium 32 as well. Mediums 28 and 32 may be any medium capable of being accessed by processing devices 26 and 30, respectively, such as RAM, flash memory, hard drives, CDs, DVDs, or any combination thereof.

[0019] User device 12, server 14, and computer 16 are connected to one another by a local or distributed network 34, such as the Internet or a telephonic network. Alternatively, user device 12, server 14, and computer 16 may be connected directly

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WO 2010/045154 PCT/US2009/060368 over a network, or any combination of private and public networks. Although the connections between user device 12, server 14, and computer 16 to network 34 are illustrated as wired connections in Figure 1, it should be understood that each device may be connected to network 34 via a wireless system, such as a wireless fidelity (“WiFi”) or cellular telephone network.

[0020] In the presently-described embodiment, a user directs a web browser program stored on medium 20 and executed by processing device 18 to a website maintained by a merchant and stored on computer 16. The user identifies and selects one or more goods and/or services offered by the merchant via the website (hereinafter “items”). When the user is ready to purchase the items, he supplies the merchant via the website with information necessary to effect a payment card transaction, such as the user’s name, telephone number, and the payment card’s expiration date and CVC. Instead of supplying the merchant with the user’s actual payment card number, however, the user generates an alternate, time-limited number by an encoding process described in more detail below. The user provides the alternate number to the merchant, who submits all the information supplied by the user to sever 14 of the financial institution that is capable of validating the transaction. Upon receipt of the information at sever 14, the financial institution decodes the alternate number as described in more detail below and, using the additional user information, determines whether to validate the payment card transaction. If the financial institution validates the transaction, it sends an indication via server 14 to computer 16 informing the merchant that the transaction has been authorized. The merchant then provides the items to the user.

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[0021] In another embodiment, the payment card transaction is effected in person or over the telephone such that user and merchant negotiate the details of the transaction in person or via a telephone line. In this embodiment, device 12 generates the alternate, time-limited number by an encoding process described below. The user provides the number to the merchant in any acceptable manner, and the process otherwise continues as described above. It should be understood that it is unnecessary for user device 12 to be connected to network 34 in such an embodiment. A notification of authorization by the financial institution may also be conveyed to the merchant over a telephonic network and may be conveyed verbally as opposed to electronically. Accordingly, it is also unnecessary for server 14 and computer 16 to be connected via network 34 in such an embodiment.

[0022] Figure 2 is a flowchart illustrating an encoding and decoding process referenced above in accordance with an embodiment of the present invention. The process is preferably implemented by software but can also be implemented by hardware, a person, or any combination thereof. In the presently-described embodiment, the software implementing the encoding process is a standalone program stored on medium 20 of user device 12 and executed by processing device 18. Alternatively, the software may be a module imbedded in the user’s web browser program, such as an add-on, a plug-in, or an Active-X control. The software implementing the decoding process is a standalone program stored on medium 28 of server 14 and executed by processing device 26. Alternatively, the software may be a module installed within the financial institution’s corporate system.

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[0023] The encoding software is installed on medium 20 of user device 12 at step 100.

In a preferred embodiment, user device 12 retrieves the software from server 14. In another embodiment, the user retrieves the software from another server or computer operatively connected to user device 12 or receives the software on a medium, such as a memory device or CD via postal mail from the financial institution or from another entity that has been tasked to maintain the software. During installation, information corresponding to the user’s payment card account is stored on medium 20, such as the user’s name, telephone number, CVC code, and expiration date. In one embodiment, this information is retrieved from the financial institution during installation of the software. Alternatively, another medium storing this information is provided to user device 12, which transfers or copies the information to medium 20. For example, flash memory containing this information may be inserted into user device 12, or another device proximate to the user device may transmit the information wirelessly to user device 12 via Bluetooth, Wi-Fi, infrared light, or by any other suitable manner. The payment card number, however, is not provided to user device 12 and is not stored on medium 20.

[0024] At step 102, the user initiates the software, which is retrieved from medium 20 and executed by processing device 18. The manner by which the user initiates the software will be dependent upon user device 12, but may generally be initiated by launching the relevant program using the operating system of user device 12. Each time the software starts, the software prompts the user to enter the PIN (via input device 22) supplied by the financial institution or selected by the user in order to gain access to the software, as represented by steps 104 and 106. At step 108, the user is presented

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WO 2010/045154 PCT/US2009/060368 with an exemplary graphical user interface (“GUI”) 50 as illustrated by Figure 3. Referring to Figure 3, GUI 50 comprises an activation button 52 (labeled “GENERATE”), the cardholder’s name at a location 54, the expiration date of the actual payment card at a location 56, the CVC for the payment card at a location 58, and a dropdown box 60 providing the user several optional timeframes, such as one week, one month, one year, etc. It should be understood that the timeframes presented by dropdown box 60 may be varied depending on what selections should be available to the user as acceptable timeframes as explained below. For example, the selectable timeframes may include individual days for the week following the time when the user accesses dropdown box 60. A location 62 identifies an alternate, time-limited payment card number generated by the process described below after the user activates button 52. The “B’s” of the number at location 62 represent the BIN, which is the same for each alternate, time-limited payment card number in that the BIN identifies the financial institution that issued the original payment card as described above or the financial institution that will validate and/or process transactions involving the generated timelimited numbers. The financial institution may use the same BIN for the time-limited payment cards as it does for the original payment cards, or it may register or use a separate BIN for the time-limited payment cards in order to route transactions involving time-limited payment cards to a specific processing center. The “X’s” represent the PAN, and the “L” represents the checksum. The PAN and checksum are generated pursuant to the process described below.

[0025] Still referring to Figures 2 and 3, at step 110, the user selects a desired timeframe from dropdown box 60 for which the user desires the time-limited payment io

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WO 2010/045154 PCT/US2009/060368 card number to be valid. At step 112, the user activates button 52, thereby instructing the software to generate a new time-limited payment card number, thus executing the program. At this point, the software normalizes the current date to 00:00:00 Greenwich Mean Time (“GMT”) regardless of the current actual time. That is, the software determines the current date and sets the time portion of the current date to 00:00:00 GMT. Based on the timeframe selected by the user at step 110 via dropdown box 60 and the normalized current date, the desired expiration date of the time-limited payment card number is determined at step 114. It should be understood that the expiration date of the time-limited number is defined in terms of GMT in that the expiration time is set to 23:59:59 GMT (approximately midnight) on the date as selected by the user at box 60. For example, if the user selects a timeframe of “1 week” on January 12^th at 1 pm Eastern Time, this time is normalized to January 12^th at 00:00:00 GMT. Thus, the expiration date is set for January 19^th at 23:59:59 GMT. In the presently-described embodiment, the expiration date of the user’s payment card is considered to be 23:59:59 GMT as of the date set forth on the original payment card. It should be understood that any time zone and/or desired time may be selected to normalize the current date, desired expiration date of the time-limited number, and the payment card’s expiration date, as long as the selected time zone and desired time are used consistently with respect to all three dates so that the three dates are analogous. That is, it is important that the three dates be converted to a common time zone for comparison.

[0026] At step 116, the software calculates the number of days between the desired expiration date of the time-limited number and the payment card’s expiration date. The

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[002η

WO201W0451S4 FCT/USZWÎMJ6GS6S number of days between the two is referred to herein as the ‘difference-days’ tor purposes of explanation. Since financial institutions generally do not Issue payment cards having an expiration date greater than three years from the date of issuance, the value of the difference-days should be less than or equal to 1096 (assuming one of the three years is a leap year, that is, 365 * 3 * 1). At step 118, the software determines the number of digits of the difference-days, and zeros are appended to the front of the difference-days until the length of the difference-days is five digits. The result is a 5digit number representative of the expiration date of the time-limited number relative to the payment card’s expiration date (i.e_r, the number of days before the payment card's expiration at which time the time-limited number will expire).

At step 120, the software appends the 3- or 4-digit PIN entered by the user at step 106 to the front of the 5-digit number established at step 118, resulting in the PAN. It should be understood that the number of digits of the PIN or the number corresponding to the expiration date of the time-iimited number may be varied depending on the number of digits available to the encoding process and desired use of the PIN, as set forth in more detail below. The software appends the PAN to the end of the BIN, resulting in a 15-dîgit number, at step 122. At step 124, a ‘Luhn check’ is performed in order to generate the checksum/last digit of the alternate, time-limited number. A Luhn check, as described in U.S. Patent No. 2,950,048 issued to H. L. Luhn, should be understood by those of ordinary skill in the art and is not, therefore, described in more detail. At step 126, the software appends the result of the Luhn check to the end of the 15-digit number established at step 122 to create a 16-digit alternate, time-limited payment card

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WO 2010/045154 PCT/US2009/060368 number. At step 128, GUI 50 displays the time-limited payment card number at location 62.

[0028] As described above with respect to Figure 1, the user provides the merchant with this alternate, time-limited payment card number to effect a payment card transaction, represented by step 130 in Figure 2. It should be understood that the user may effect the transaction by providing the alternate, time-limited payment card number to the merchant in a face-to-face transaction or via a telephone. Referring to Figures 1 and 2, the merchant transmits the information provided by the user during the user/merchant payment card transaction, including the CVC, expiration date, name, and telephone number associated with the user’s payment card, along with the alternate payment card number and the date on which the payment card transaction was effected, to the financial institution associated with the BIN at step 130. In the presently-described embodiment, this information is transmitted to server 14 via computer 16, but may be accomplished by any other means, such as electronically or verbally over a telephone line.

[0029] The financial institution receives the information relevant to the payment card transaction from the merchant at step 132. In the current embodiment, software stored on medium 32 and executed by processing device 30 transmits the information to the financial institution. Alternatively, the merchant may provide the information to the financial institution over a telephone line. At step 134, the checksum digit of the alternate payment card number is extracted and compared to the result of a Luhn check of the BIN and PAN to ensure the alternate number may be a valid payment card number. If not, the transaction is rejected at step 136.

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[0030] Otherwise, the financial institution software uses the other information transmitted by the merchant to the financial institution to locate the user’s account, at step 138. The program matches the CVC, name, telephone number, and expiration date transmitted by the merchant to a CVC, name, telephone number, and expiration date associated with an account located within the financial institution’s system. In another embodiment, a subset of this information, such as the name and telephone number or the CVC and telephone number, is used to locate the corresponding account maintained by the financial institution. If multiple payment cards are associated to the user or the account, the program uses the CVC and/or expiration date to identify the specific payment card to which the transaction relates.

[0031] In another embodiment, user device 12 (Figure 1) transmits information capable of identifying the user, other than information corresponding to the user’s payment card number, along with the time-limited number. The other information could be a device signature, such as a service-subscriber or international mobile subscriber identity (“IMSI”). An IMSI is a unique number associated with user device 12 and is able to uniquely identify the corresponding user within the financial institution’s system as long as the IMSI is stored by the institution in the user’s account. Alternatively, user device 12 transmits a sequence of alphanumeric characters unique to the user’s account at the financial institution. The financial institution uses this unique sequence, which is stored in the user’s account, in order to locate the user’s account. It should be understood from the above description that the user’s actual payment card number, or the PAN of the actual payment card number, is not required to locate the user’s account.

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[0032] At step 140, the financial institution program extracts the other four digits of the

PAN and compares those digits to the PIN stored by the financial institution in the user’s account identified at 138. If the extracted digits and the stored PIN do not match, the program rejects the transaction at step 136.

[0033] Otherwise, at step 142, the financial institution software normalizes the date on which the payment card transaction was effected to 00:00:00 GMT in a manner identical to that described above with respect to step 114. At step 144, the financial institution software calculates the number of days between the normalized transaction-effected date and the payment card’s expiration date. At step 146, the software extracts the last five digits of the PAN of the alternate number and, at step 148, compares the extracted digits to the number of days determined at step 144. If the number of days calculated at step 144 is less than the extracted five digits, this indicates that the alternate, timelimited number has expired. The transaction is thus rejected at step 136. Otherwise, the transaction is authorized at step 150.

[0034] It should be understood that the above process allows the creation of an alternate payment card number that is valid for a length of time selected by the user. Thus, if the alternate number is stolen or otherwise becomes public information, the number will automatically be invalidated and unusable after the selected length of time. Additionally, if the information corresponding to the payment card transaction as described above is stolen or otherwise compromised, the possessor of the information is incapable of discerning the user’s actual payment card number from the information. The above process allows the user to generate one unique time-limited payment card number for each day that the alternate number is desired to expire.

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[0035] Figure 4 illustrates an encoding and decoding process in accordance with another embodiment of the present invention. In this embodiment, the user device program uses five digits of the PAN to represent the date on which the alternate, timelimited payment card number will expire, generated in the same manner as described above with respect to the embodiment of Figure 2. Assuming five digits of the PAN are used for this date number, 100,000 different numbers (0 to 99,999) may be stored in these digits. The greatest amount of time that the user may select for the alternate number to expire coincides with the difference between the card's issue date and its expiration date. Since the expiration date of any payment card is usually three years or less from the date of issuance, the maximum time limit is most likely 1096 days (allowing fora leap year). Accordingly, 91 alternate, time-limited payment card numbers can be generated for each desired expiration date within the 3 years. That is, the 100,000 numbers divided by the 1096 days results in approximately 91 numbers per day. Thus, in the presently-described embodiment, each day within the three years is associated with a range of 91 numbers within the 100,000 available numbers. For example, the payment card’s expiration date is associated with the first set of 91 numbers; that is, 0 through 90. The day prior to the payment card’s expiration date is associated with the second set of 91 numbers - 91 through 180; and so on.

[0036] The process illustrated in Figure 4 is identical to that of Figure 2 with respect to steps 100 through 116, and the number of days between the normalized, desired expiration date of the time-limited number and the payment card’s expiration date is calculated at step 116 as described above with respect to Figure 2. In the presentlydescribed embodiment with respect to Figure 4, the number of days determined at step

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116 of Figure 2 is multiplied by the day-range (91, in this case) to thereby find the smallest number within the range associated with the selected, desired expiration date, at step 200. The software adds one less than the length of the day-range slotted for each day (90, in this case) to the smallest number (calculated at step 200) to thereby determine the greatest number within the range, at step 202. A random number generator effected in the user software and bounded by the smallest number (step 200) and greatest number (step 202) within the day-range creates a random number within the range at step 204. As described above, zeros are appended to the random number as necessary, at step 206, to generate a 5-digit number. This 5-digit number corresponds to the expiration date of the time-limited number in that it can be used along with other information associated to the actual payment card to determine the expiration date of the time-limited number. This number is appended to the PIN to form the PAN. The above process replaces the process described above with respect to step 118 of Figure 2, and process flow proceeds to step 146 and continues in a manner identical to the process described above with respect to Figure 2.

[0037] Still referring to Figure 4, the financial institution program extracts the five digits representing the desired expiration date, at step 146. The financial institution program divides the extracted number by the day-range of numbers for each expiration date (91 in the presently described example) and rounds down to the nearest whole number or integer, at step 208. The result is the number of days between the desired expiration date of the alternate number and the payment card’s expiration date. Process flow proceeds to step 148 and continues in a manner identical to that described above with respect to Figure 2.

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[0038] The proœss described above with respect to Figure 4 provides the ability to generate multiple time-limited payment card numbers for each desired expiration date. Thus, for example, if the user generates multiple numbers for respective transactions, the system likely generates different numbers for most or all of the transactions. If one of the numbers is stolen, it may therefore be possible to identify the particular transaction involved, and thereby the particular vendor repository from which the number was stolen. It is also possible to generate additional time-limited numbers for a specific timeframe even after one such number becomes compromised.

[0039] Figure 5 illustrates an encoding and decoding process in accordance with another embodiment of the present invention. In this embodiment, process flow proceeds to step 206 in a manner identical to that described above with respect to Figure 4. Step 120 (Figure 4) is replaced by step 300 where the user program on device 12 creates the PAN by interspersing the PIN and the 5-digit number generated at step 206. For example, each digit of the PIN is inserted between two adjacent digits of the 5-digit number. It should be understood that the manner by which the PIN and the 5-digit number are interspersed or rearranged can vary as long as the financial institution reassembles the PIN and the 5-digit number using a corresponding method, as described below. Moreover, the method of interspersion can vary from one user to another.

[0040] Process flow continues to step 138 in a manner identical to that described above with respect to Figure 4. At step 302, the financial institution program reassembles the PIN and the 5-digit number from the PAN in reverse of the manner by which the PIN and 5-digit number were interspersed at step 300. Continuing the example above, for

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WO 2010/045154 PCT/US2009/060368 instance, each digit of the PIN would be extracted from between the adjacent digits of the 5-digit number where they had been inserted. Process flow proceeds to step 140 and then continues in a manner identical to that described above with respect to Figure 4. It should be understood that the above process intersperses the PIN associated with the user’s payment card in order to obscure the PIN’s visibility.

[0041] Figure 6 illustrates another encoding and decoding process in accordance with another embodiment of the present invention. In this embodiment, process flow proceeds to step 300 in a manner identical to that described above with respect to Figure 5. Because the user program is constructed to remember the location at which it inserted the digits of the PIN into the positions within the PAN, the user program extracts the last digit of the PIN, regardless of its location within the PAN at step 400. At step 402, the user program performs a Luhn check on the remaining 15 digits of the number and places the result in the location where the last digit of the PIN was extracted. At step 404, the user program extracts the third digit of the PIN and performs a Luhn check on the remaining 15 digits of the number. At step 406, the user program places the result of the Luhn check in the location where the third digit of the PIN was extracted. At step 408, the program extracts the second digit of the PIN and replaces it with the result of a Luhn check on the remaining 15 digits. At step 410, the program extracts the first digit of the PIN and replaces it with the result of a Luhn check on the remaining 15 digits. Process flow continues to step 138 in a manner identical to that described above with respect to Figure 5.

[0042] The financial institution program is constructed to know the locations where the user program inserted the digits of the PIN into the PAN, and, thus, the locations where

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WO 2010/045154 PCT/US2009/060368 the Luhn checks replaced the digits of the PIN within the PAN. Thus, at step 412, the financial institution program extracts the number that replaced the first digit of the PIN and performs a Luhn check at step 414. If the result is anything other than the number extracted at step 412, the transaction is denied at step 136. Otherwise, at step 416, the financial institution program places the first digit of the PIN as stored in the user’s account maintained by the financial institution in the location where the number was extracted at step 412. At step 418, the financial institution program extracts the number that replaced the second digit of the PIN and performs a Luhn check at step 420. If the result is anything other than the number extracted at step 418, the transaction is rejected at step 136. Otherwise, at step 422, the program places the second digit of the PIN as stored by the financial institution in the location where the number was extracted at step 418.

[0043] The financial institution program extracts the number that replaced the third digit of the PIN at step 424 and performs a Luhn check at step 426. If the result is anything other than the number extracted at step 424, the transaction is denied at step 136. Otherwise, at step 428, the financial institution program inserts the third digit of the PIN as stored in the user’s account maintained by the financial institution into the PAN at the location where the number was extracted at step 424. At step 430, the financial institution program extracts the number that replaced the fourth digit of the PIN and performs a Luhn check at step 432. If the result is anything other than the number extracted at step 430, the transaction is denied at step 136. Otherwise, at step 434, the financial institution program places the fourth digit of the PIN as stored by the financial institution in the location where the number was extracted at step 430. Process flow

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WO 2010/045154 PCT/US2009/060368 proceeds to step 302 and continues in manner identical to that described above with respect to Figure 5.

[0044] It should be understood that the above process changes each digit of the PIN, which is stored at different locations within the PAN of the time-limited payment card number. Additionally, the alteration of each digit is dependent on the other digits and the prior changes. Accordingly, if an attempt to use the time-limited payment card number involves changing any of the digits, the transaction will be denied. Moreover, the PIN is not visible within the PAN.

[0045] Figure 7 illustrates an encoding and decoding process in accordance with another embodiment of the present invention, in which the information stored on user device 12 (Figure 1 ) includes an eight digit random number specific to the user (referred to hereinafter as the “randomizer” for simplicity). The financial institution stores the randomizer in the user’s account.

[0046] Referring to Figure 7, installation at step 100 occurs in the same manner as described above with respect to Figure 2. Process flow proceeds from step 100 to step 410 in a manner identical to that described above with respect to Figure 6. At step 500, the user program adds (sums) the randomizer to the PAN generated at step 410. At step 502, the user program analyzes the length of the summation calculated at step 500. If the summation is a ten digit number, the leading “1” is truncated, resulting in a 9digit PAN. Process flow proceeds to step 140, as it also would if the summation was not a 10-digit number (determined at step 500), and continues in a manner identical to that described above with respect to Figure 6.

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[0047] At step 506, the financial institution program extracts the PAN from the timelimited number. At step 508, the financial institution program compares the randomizer associated with the user’s payment card stored by the financial institution to the 9-digit PAN. If the randomizer is greater than the PAN, a leading “1” is appended to the front of the PAN at step 510. The financial institution program subtracts the randomizer from the PAN at step 512. The program reinserts the resulting 9-digit PAN into the timelimited payment card number in the appropriate location - between the BIN and the checksum. Process flow proceeds to step 412 and continues in a manner identical to that described above with respect to Figure 6.

[0048] The process described above with respect to Figure 7 includes the addition of a random number specific to the user. This number is stored on the user’s device 12 and the financial institution’s server 14. Any attempt to decode the time-limited payment card number generated by the above process without the randomizer will be unsuccessful.

[0049] With reference to Figure 7, in another embodiment, the information stored on user device 12 (Figure 1 ) includes two digits of a 4-digit validation number and six digits of the 8-digit randomizer. As set forth above, the financial institution maintains all the information corresponding to the user, including all four digits of the validation number and all eight digits of the randomizer.

[0050] The PIN entered by the user at step 106 is comprised of the other two digits of the 4-digit validation number and the other two digits of the 8-digit randomizer. It should be understood that the location of the remaining digits of the validation and randomizer number within the PIN may vary, provided that the software is constructed to know the

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WO 2010/045154 PCT/US2009/060368 location of each digit. For example, the two digits of the validation number may be the first two digits of the PIN or the middle two digits, with the remaining two locations being occupied by the two missing digits of the randomizer. The digits may also be reversed with respect to how they should appear in the validation number and randomizer. For example, the last digit of the PIN may be the first digit of the complete validation number, and the first digit of the PIN may be the third digit of the complete validation number. Thus, it should be apparent that the location of each digit within the PIN is inconsequential on the condition that the software is constructed to identify the location of each digit.

[0051] In the present embodiment, the two digits of the validation number are extracted from the PIN entered by the user and joined to the two digits of the validation number within the file stored on medium 20 to produce the complete validation number at step 106. Similarly, the user program extracts the two digits of the randomizer number from the PIN and joins them to the six digits of the randomizer within the file stored on medium 20 to produce the complete randomizer at step 106. In the presently-described embodiment, the validation number replaces the PIN number for the remainder of the process, which proceeds to step 108 and continues in a manner otherwise identical to that described above. For example, the validation number (instead of the PIN) and the 5-digit number are interspersed at step 300 and reassembled at step 302. Process flow proceeds in a manner similar to that described above.

[0052] At step 148, the financial institution program compares the reassembled validation number to the validation number specific to the user maintained by the

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WO 2010/045154 PCT/US2009/060368 financial institution. If the validation numbers do not match, the transaction is denied at step 136. Otherwise, the transaction is validated at step 150.

[0053] The process described above prevents the information necessary to generate a time-limited payment card number from being accessible from a single location. That is, other than the financial institution, no entity or device possesses the entire validation number and/or randomizer, not even the user. Thus, if user device 12 is stolen, the culprit should be unable to generate a valid number without knowing the PIN.

[0054] It should also be understood that the encoding and decoding processes described above are exemplary processes, and various processes may be used. Moreover, different processes can be used for one or more users so that the encoding and decoding process for one user may be different from the process for another user. As a result, the security of the above-described system and method is increased because discovery of the method associated with one user would be ineffective in compromising the confidential information of another user to which a different method has been associated.

[0055] Referring to Figures 1 and 7, in another embodiment, a file containing the information corresponding to the user’s payment card, along with the two digits of the validation number and the six digits of the randomizer, is stored on medium 20 during installation at step 100. Alternatively, the file may be stored on medium 20 prior to or subsequent of the installation of the software at step 100. The file may be downloaded from server 14 or from another computer maintained by a third-party operatively connected to user device 12, or may even be mailed via postal mail to the user by the financial institution or third-party.

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[0056] It should be understood that the number of digits apportioned to the validation number/PIN and to the number representative of the desired expiration date of the timelimited payment card number may be varied depending on the available number of digits and the desired use of the digits without departing from the scope of the presently-described embodiments. For example, credit cards issued by American Express are 15 digits in length, as compared to the 16-digit numbers discussed above. To accommodate for one less digit, a digit can be removed from either the digits allotted to the validation number/PIN or to the portion representative of the desired expiration date. Reducing the number of digits allotted to the desired expiration date changes the number of available time-limited credit card numbers per desired expiration day. For instance, reducing the number of digits for the number representative of the desired expiration from five to four reduces the number of different time-limited numbers that can be generated for each day from 91 to 9 (10,000 * 1096). Furthermore, financial institutions associated with a specific BIN may authorize other financial institutions to use the same BIN. In this scenario, digits in the PAN following the BIN are used to identify which payment card numbers have been issued by the authorized institutions. Transactions involving payment card numbers that include the specific BIN are routed to the authorizing institution. The authorizing institution then routes the transactions to the authorized institution associated with the digits in the PAN set aside to uniquely identify the authorized institutions to which the relevant payment card number corresponds. In this case, digits within the PAN available for use in the processes described above are reduced. The encoding and decoding process handles a reduced amount of available digits within the PAN as described above.

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[0057] Furthermore, it may be desirable to allot more available, time-limited payment card numbers to one desired expiration date than to another. For instance, assuming five digits of the PAN are selected to represent the desired expiration date of the timelimited payment card number as described above, it may be desirable to allot half of the available numbers, or 50,000, to be used for time-limited numbers expiring on the same date as the actual payment card’s expiration date. In this case, only the remaining 50,000 numbers are available for other expiration dates, thereby reducing the available numbers per desired expiration day to approximately 45 (50,000 * (1096 -1 )).

[0058] Similarly, it may be desirable to allow a set of time-limited numbers for a specific use. For example, it may be advantageous to allocate 50,000 of the available numbers to be used as single-use payment card numbers. That is, each generated number based on one of these available numbers may be used once only. In such an embodiment, the user does not select a timeframe or an expiration date. Instead, the encoding program generates a time-limited number by randomly selecting a number from the available range of numbers. The process otherwise proceeds as described above. Once the random number is decoded and extracted from the time-limited number, the decoding program determines if it falls within the range of acceptable numbers and, if so, whether the number has been previously used. If the number has not been involved in a previous transaction, the financial institution authorizes the current transaction and removes the number from the list of useable numbers. Otherwise, the transaction is rejected. Thus, if another transaction includes the same number from the range of acceptable numbers, it will be rejected. This prevents a

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WO 2010/045154 PCT/US2009/060368 stolen or compromised, alternate number from being used again once it has been used in a transaction.

[0059] In addition, the length of the PIN issued by the financial institution may be varied without departing from the scope of the present invention. Furthermore, the purpose of each digit within the PIN may be varied depending on the desired encoding and decoding process. For example, the financial institution may issue a 5-digit PIN, wherein one of the digits is part of the validation number and the remaining four digits are part of the randomizer. In this instance, three digits of the validation number are stored on medium 20 of user device 12, and four digits of the randomizer are stored on the medium.

[0060] It should also be understood that the present invention is not directed solely to transactions occurring over a network, such as the Internet. For example, a user may contact a merchant by telephone and provide the information necessary to effect a payment card transaction, including the alternate, time-limited payment card number, over the phone. In this instance, user device 12 generates the number in the manner described above, and the user verbally provides the number and other necessary information to the merchant. Moreover, a user also can verbally provide the time-limited number in a face-to-face transaction with a merchant. At this time, the user also provides the merchant with other information necessary to effect a payment card transaction, which may include the user’s name, CVC, and telephone number. Thus, it should be understood that the processes described above may be employed in both a connected and disconnected manner. That is, user device 12 (Figure 1) may be a personal computer operatively connected to a merchant and a financial institution via a

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WO 2010/045154 PCT/US2009/060368 physical network in a manner that allows the user device to interact with systems maintained by the merchant and/or financial institution. Alternatively, user device 12 may be a personal data assistant that is not connected to a system maintained by the merchant or financial institution. In such an embodiment, information stored within or generated by the user device may be provided to the merchant or financial institution by the user, the merchant, or by any other suitable manner.

[0061] It should be understood that user device 12 (Figure 1) need not be an interactive device, but can be a non-interactive device, such as a smart pass, smartcard, or key fob. In such an embodiment, when the device is within range of an associated reader and the details of the transaction have been established, the device transmits the relevant information to the receiver, including a time-limited payment card number and an expiration date for the number. In the this embodiment, the expiration date is set to the default time period established by the corresponding financial institution. For example, user device 12 selects 1 week as the timeframe for the alternate, time-limited number to expire by default. It should be understood that, because the alternate, timelimited number is transmitted by the device to the receiver, a display, such as display 24 (Figure 1 ), is unnecessary in such an embodiment. It should also be understood that user device 12 may be pre-programmed to generate alternate, time-limited numbers set to expire at a fixed interval. Accordingly, an input device, such as input device 22 (Figure 1), that allows the user to select a desired expiration timeframe or date is unnecessary in such an embodiment.

[0062] It should also be understood that financial institutions may use both known and later-developed encryption methods and processes in conjunction with the above

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WO 2010/045154 PCT/US2009/06M68 described embodiments. Such encryption techniques may be use in combination with the above processes without the necessity to materially alter foe processes described above. Furthermore, multiple encryption techniques may be used to aid the security methods described above without departing from the scope of the present Invention.

[0063] While one or more preferred embodiments of the invention have been described above, it should be understood that any and all equivalent realizations of the present invention are included within the scope thereof. The embodiments depicted are presented by way of example only and are not intended as limitations upon the present invention. Thus, it should be understood by those of ordinary skill in this art that the present invention is not limited to these embodiments since modifications can be made. Therefore, it is contemplated that any and all such embodiments are Included in the present invention as may fell within the scope thereof.