Patent Publication Number: US-2019197522-A1

Title: Methods and systems to pay using unique string

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of and priority to Singapore Patent Application No. 10201710740R filed Dec. 22, 2017. The entire disclosure of the above application is incorporated herein by reference. 
     FIELD 
     The present disclosure relates to payment transactions from users to merchants and, more particularly to, performing an alternate payment transaction method using a unique string that can be used even when a physical payment card, cash or mobile phone is not available with the user at the time of making payment transaction. 
     BACKGROUND 
     This section provides background information related to the present disclosure which is not necessarily prior art. 
     Nowadays, most users use several banking cards, such as credit cards, debit cards, prepaid cards, etc., for performing financial transactions (e.g., payment transaction). The various banking cards are herein referred to as payment cards. The payment cards are increasingly used for making payments at point-of-sale (POS) terminals available at various facilities including, but not limited to, retail establishments (e.g., merchants like McDonald&#39;s™ or Walmart™) or businesses (e.g., ticket reservation centers) that handle cash or credit transactions. The payment cards are generally swiped or inserted into a POS terminal present at these facilities for initiating the financial transaction. 
     In some scenarios, instead of swiping or inserting the payment card into the POS terminal, some users can store the payment cards in digital format in their mobile phones or in payment applications to complete the payment. In other alternate methods, users can typically scan a machine-readable code such as Quick Response (QR) code present at the payment counters using an application installed on their mobile phones. Once the QR code is accepted by the application, the user&#39;s payment card account is verified to process the transaction. Alternatively, the users can make online payment transactions using their mobile phones or any other device equipped with internet access, wherein the users need to provide the relevant details such as payment card number, expiry date, Card Verification Value (CVV), one-time password (OTP) details, billing details and the like. 
     In the above payment transaction methods, the user is required to either carry the physical payment card and/or should have corresponding payment applications present in his mobile phone with adequate internet connectivity to carry out the payment transaction. However, sometimes, the user may not have the payment card with him, or his mobile phone may not be equipped with payment applications or with adequate internet bandwidth, while visiting a merchant facility. In such scenarios, the user may not be able to make payment transactions. Also, keeping the cash, physical payment card and payment card details/applications in the mobile phone may not be safe all the times, and can lead to compromise in the overall personal and financial security. Further, making an online transaction at the online merchant interface requires remembering and inputting a lot of payment card details and billing details by the user, leading to a frustrating experience. 
     Accordingly, there is a need for techniques that can allow the users to carry out payment transactions at merchant facilities without using the physical payment card, or without need to include a lot of payment card details in the online merchant interface for the completion of the financial transaction. 
     SUMMARY 
     This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. Aspects and embodiments of the disclosure are set out in the accompanying claims. 
     Various embodiments of the present disclosure provide systems, methods, electronic devices and computer program products to pay using unique string to the merchants. 
     In an embodiment, a method for facilitating a payment transaction from an issuer account of a user to an acquirer account of a merchant without swiping or entering card details of a payment card at a merchant interface of the merchant is disclosed. The method includes receiving, by a server system associated with a payment network, a payment transaction request. The payment transaction request includes at least a payment string uniquely associated with the payment card linked with the issuer account and a transaction amount to be paid to the merchant. The method includes verifying a validity of the payment string based on at least one rule set. Upon successful validation of the payment string, the method includes retrieving issuer account information associated with the issuer account based on at least a part of the payment string. Furthermore, the method includes facilitating the payment transaction based at least on the retrieved issuer account information from the issuer account to the acquirer account. 
     In another embodiment, a server system configured to facilitate a payment transaction from an issuer account of a user to an acquirer account of a merchant without swiping or entering card details of a payment card at a merchant interface of the merchant is provided. The server system includes a communication interface configured to receive a payment transaction request comprising at least a payment string uniquely associated with the payment card linked with the issuer account and a transaction amount to be paid to the merchant. The server system further includes at least one processor in operative communication with the communication interface. The at least one processor is configured to verify a validity of the payment string based on at least one rule set. Upon successful validation of the payment string, the at least one processor is further configured to retrieve issuer account information associated with the issuer account based on at least a part of the payment string. The at least one processor is further configured to facilitate the payment transaction based at least on the retrieved issuer account information from the issuer account to the acquirer account. 
     In yet another embodiment, a server system configured to facilitate a payment transaction from an issuer account of a user to an acquirer account of a merchant without swiping or entering card details of a payment card at a merchant interface of the merchant is provided. The server system includes a database comprising a mapping table. The mapping table is configured to store mapping of a plurality of predefined length alphanumeric codes and a plurality of issuer account information associated with a plurality of users. The server system includes a communication interface configured to receive a payment transaction request comprising at least a payment string uniquely associated with the payment card linked with the issuer account and a transaction amount to be paid to the merchant. The payment string includes a predefined length alphanumeric code of the plurality of predefined length alphanumeric codes. The server system includes a memory comprising executable instructions and a processor communicably coupled to the communication interface and the database. The processor is configured to execute the instructions to cause to the server system to verify a validity of at least the predefined length alphanumeric code of the payment string based on at least one rule set. Upon successful validation of the predefined length alphanumeric code, the server system is further caused to retrieve an issuer account information associated with the issuer account based on matching the predefined length alphanumeric code in the mapping table. The server system is further caused to facilitate the payment transaction based at least on the retrieved issuer account information from the issuer account to the acquirer account. 
     Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. With that said, for a more complete understanding of example embodiments of the present technology, reference is now made to the following descriptions taken in connection with the accompanying drawings in which: 
         FIG. 1  illustrates an example representation of an environment, related to at least some example embodiments of the present disclosure; 
         FIG. 2  illustrates an example representation of a payment string generated for facilitating a payment transaction, in accordance with an example embodiment of the present disclosure; 
         FIG. 3  represents a sequence flow diagram representing a completion of a payment transaction using a payment string at a POS terminal, in accordance with an example embodiment; 
         FIG. 4  represents a sequence flow diagram representing a completion of a payment transaction using a payment string at a POS terminal, in accordance with another example embodiment; 
         FIG. 5  represents a simplified schematic representation depicting a mapping table stored in a payment server for verifying a payment string for a completion of a payment transaction, in accordance with an example embodiment; 
         FIG. 6  represents a simplified block diagram representation of generation of a Human Generated Password (HGP) by a user, in accordance with an example embodiment; 
         FIG. 7  illustrates a flow diagram of a method for carrying out payment transaction using payment string, in accordance with an example embodiment; 
         FIG. 8  is a simplified block diagram of a server system used for payment transaction using payment string, in accordance with one embodiment of the present disclosure; 
         FIG. 9  is a simplified block diagram of a POS terminal used for payment transaction using payment string, in accordance with one embodiment of the present disclosure; 
         FIG. 10  is a simplified block diagram of an issuer server for payment transaction using payment string, in accordance with one embodiment of the present disclosure; 
         FIG. 11  is a simplified block diagram of an acquirer server used for payment transaction using payment string, in accordance with one embodiment of the present disclosure; 
         FIG. 12  is a simplified block diagram of a payment server used for payment transaction using payment string, in accordance with one embodiment of the present disclosure; and 
         FIG. 13  shows simplified block diagram of a user device capable of implementing at least some embodiments of the present disclosure. 
     
    
    
     The drawings referred to in this description are not to be understood as being drawn to scale except if specifically noted, and such drawings are only exemplary in nature. 
     Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION 
     Embodiments will be described, by way of example only, with reference to the drawings. The description and specific examples included herein are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
     In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. It will be apparent, however, to one skilled in the art that the present disclosure can be practiced without these specific details. 
     Reference in this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. The appearance of the phrase “in an embodiment” in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Moreover, various features are described which may be exhibited by some embodiments and not by others. Similarly, various requirements are described which may be requirements for some embodiments but not for other embodiments. 
     Moreover, although the following description contains many specifics for the purposes of illustration, anyone skilled in the art will appreciate that many variations and/or alterations to said details are within the scope of the present disclosure. Similarly, although many of the features of the present disclosure are described in terms of each other, or in conjunction with each other, one skilled in the art will appreciate that many of these features can be provided independently of other features. Accordingly, this description of the present disclosure is set forth without any loss of generality to, and without imposing limitations upon, the present disclosure. 
     The term “payment account”, used throughout the description, refers to a financial account that is used to fund the financial transaction (interchangeably referred to as “payment transaction”). Examples of a payment account include, but are not limited to a savings account, a credit account, a checking account and a virtual payment account. The payment account may be associated with an entity such as an individual person, a family, a commercial entity, a company, a corporation, a governmental entity, a non-profit organization and the like. In some scenarios, a payment account may be a virtual or temporary payment account that can be mapped or linked to a primary payment account, such as those accounts managed by PayPal®, and the like. 
     The term “payment network”, used throughout the description, refers to a network or collection of systems used for transfer of funds through use of cash-substitutes. Payment networks may use a variety of different protocols and procedures in order to process the transfer of money for various types of transactions. Transactions that may be performed via a payment network may include product or service purchases, credit purchases, debit transactions, fund transfers, account withdrawals, etc. Payment networks may be configured to perform transactions via cash-substitutes, which may include payment cards, letters of credit, checks, financial accounts, etc. Examples of networks or systems configured to perform as payment networks include those operated by MasterCard®, VISA®, Discover®, American Express®, etc. 
     The term “payment card”, used throughout the description, refers to a physical or virtual card linked with a financial or payment account that may be used to fund a financial transaction to a merchant or any such facility via the associated payment account. Examples of the payment card include, but are not limited to, debit cards, credit cards, prepaid cards, virtual payment numbers, virtual card numbers, forex cards, charge cards and stored-value cards. A payment card may be a physical card that may be presented to the merchant for funding the payment. Alternatively, or additionally, the payment card may be embodied in form of data stored in a user device, where the data is associated with payment account such that the data can be used to process the financial transaction between the payment account and a merchant&#39;s financial account. 
     Various example embodiments of the present disclosure provide methods, systems, user devices and computer program products for making payment using unique payment strings in facilities such as supermarkets, restaurants, hotels, ticket counters, e-commerce websites and the like, thereby eliminating the need to carry physical payment cards, cash or the mobile phone for processing the payment transaction. 
     In various example embodiments, the present disclosure provides a merchant interface that can be used by the user/customer to enter a unique payment string to process a payment transaction. A server system is configured to receive the payment transaction request that includes a payment string associated with a payment card linked with an issuer account of a user and the transaction amount. The server system is configured to verify the payment string based on predefined rule sets. The payment string includes a combination of a user generated password (hereinafter referred to as human generated password (HGP)), a predefined length alphanumeric code (hereinafter referred to as chord) and a personal identification number (PIN) associated with the payment card of the user. The HGP is a three digit long dynamic password configured to change based on a predefined pattern such as based on days of months, days of weeks and the like. The chord (e.g., 404 chord) is six character long alphanumeric code (A-Z, 0-9) unique to the payment card of the user. The PIN is a four-digit number and may be verified by the server system. All three parts of the unique string can be bundled together, and it can be parsed by one or more server systems to extract relevant information such as issuer account information for effecting payment transaction from the issuer account to the acquirer account. 
     In one embodiment, the user enters the unique payment string at the POS terminal or any other merchant interface such as online merchant interface, the POS terminal (or the online merchant interface) sends a payment transaction request to an acquirer server (an example of the server system) associated with an acquirer bank of the merchant. The payment transaction request comprises the payment string and the transaction amount, among other data. The acquirer server sends the payment string along with other payment details such as transaction amount to an interchange server (i.e., a payment server, an example of the server system). The payment server checks for the validity of the format of the unique payment string, and parses the payment string to extract the issuer account information of the user. More specifically, the payment server extracts the alphanumeric part i.e., the chord of the payment string, and retrieves the issuer account information associated with the issuer account from a mapping table accessible to the payment server. 
     Once, the payment server has the issuer account details, the payment server sends the HGP, transaction amount and the issuer account information to an issuer server (an example of the server system) associated with an issuer bank of the user. The issuer server verifies the HGP (and optionally PIN) of the payment string and processes the payment transaction. It is noted that verifying the HGP at the issuer server acts as an added layer of security for the payment transaction. In some embodiments, the issuer server can verify the PIN that is a part of the string before realizing the payment from the issuer account to the acquirer account. Alternatively, the PIN can also be verified at the payment server, and the payment server only provides the HGP part of the payment string and the issuer account information to the issuer server. Once the HGP part and the PIN are verified, the payment transaction is completed from the issuer account to the acquirer account. 
       FIG. 1  illustrates an example representation of an environment  100 , in which at least some example embodiments of the present disclosure can be implemented. In the illustrated embodiment, a facility  105  is shown. Examples of the facility  105  may include any retail shop, supermarket or establishment, government and/or private agencies, ticket counters, or any such place or establishment where users visit for performing financial transaction in exchange of any goods and/or services or any transaction that requires financial transaction between the user and the facility  105 . 
     As can be seen from the environment  100 , a customer  115  (hereinafter referred to as user  115 ) is standing near a payment desk  120  to make the financial transaction to a merchant  110  for a product purchased by the user  115  from the facility  105 . The facility  105  also includes a merchant interface  125 . Examples of the merchant interface  125  include a point of sale device or a point of sale terminal  125  (hereinafter interchangeably referred to as ‘POS terminal  125 ’) placed on the payment desk  120  where the payment transaction can be initiated. In various embodiments, the merchant interface  125  can be a merchant telephone, merchant computer system. Alternatively or additionally, the merchant interface  125  can also be an online merchant interface such as a merchant website, mobile or desktop applications, or third party websites or applications using which the user  115  may purchase goods or service from a remote location or with in-store presence. 
     Various embodiments of the present disclosure provide mechanisms such that the user  115  is only required to enter a payment string (such as the payment string  125   a ) at the merchant interface such as the POS terminal  125  instead of carrying the physical payment cards to the facility  105  and swiping the payment card at the POS terminal  125 . Accordingly, the user  115  needs to spend relatively less time at the POS terminal  125  for completing the payment transaction, which leads to reduction in overall time required for completing the payment transaction. As shown in the environment  100 , the user  115  is entering a unique payment string  125   a  (exemplarily depicted as **** . . . ) (hereinafter alternatively referred to as string  125   a ) using the POS terminal  125 . Alternatively, in the embodiment of the merchant interface being the online merchant interface, the user  115  may use his mobile phone or any other electronic device while purchasing a product online from the merchant website using the internet and be requested to enter the string  125   a  to initiate the payment transaction. 
     In a non-limiting example, verification of the string  125   a  and authentication of the user&#39;s bank account with sufficient funds for making a transaction of ‘X’ amount to complete the payment transaction is performed by a combination of an issuer server  135 , an acquirer server  130  and a payment server  140 . In one embodiment, the payment server  140  is associated with a payment network  145 . The payment network  145  may be used by payment cards issuing authorities as a payment interchange network. Examples of payment interchange network include, but not limited to, Mastercard® payment system interchange network. The Mastercard® payment system interchange network is a proprietary communications standard promulgated by Mastercard International Incorporated® for the exchange of financial transaction data between financial institutions that are members of Mastercard International Incorporated®. (Mastercard is a registered trademark of Mastercard International Incorporated located in Purchase, N.Y.). 
     The issuer server  135  is associated with a financial institution normally called an “issuer bank” or “issuing bank” or simply “issuer”, in which the user  115  may have an account, which issues a payment card, such as a credit card or a debit card. The issuer server  135  also facilitates unique string based electronic payment transaction facility to the user  115 , described in various embodiments of the present disclosure. The unique payment strings (i.e., the string  125   a ) are linked to payment cards associated with the user  115 . The user  115 , being the cardholder, can use any of the payment strings associated with the payment cards to tender payment for a purchase from the merchant  110 . 
     To accept payment using the payment string based electronic payment transaction, the merchant  110  must normally establish an account with a financial institution that is part of the financial payment system. This financial institution is usually called the “merchant bank” or the “acquiring bank” or “acquirer bank” or simply “acquirer”. The acquirer server  130  is associated with the acquirer bank. 
     Using the payment network  145 , the computers of the acquirer/the acquirer server  130  or the merchant processor will communicate with the computers of the issuer/the issuer server  135  to determine whether the user&#39;s account is in good standing and whether the purchase is covered by the user&#39;s available account balance. Based on these determinations, authorization of the payment transaction is declined or accepted. When the authorization is accepted, the available balance of user&#39;s account  112  is decreased. Normally, a charge is not posted immediately to a user&#39;s account because bankcard associations, such as Mastercard International Incorporated®, have promulgated rules that do not allow a merchant to charge, or “capture,” a transaction until goods are shipped or services are delivered. When the merchant  110  ships or delivers the goods or services, the merchant  110  captures the transaction by, for example, appropriate data entry procedures on the POS terminal  125 . If the user  115  cancels a transaction before it is captured, a “void” is generated. If the user  115  returns goods after the transaction has been captured, a “credit” is generated. 
     After a transaction is captured, the transaction is settled between the merchant  110 , the acquirer and the issuer. Settlement refers to the transfer of financial data or funds between the merchant&#39;s account, the acquirer, and the issuer, related to the transaction. Usually, transactions are captured and accumulated into a “batch”, which is settled as a group. 
     A user device (e.g., a mobile phone or desktop computer of the user  115 ), the merchant device (e.g., the POS terminal  125 ) associated with the merchant interface, the issuer server  135 , the acquirer server  130  and the payment server  140  communicate with one another using a network  150 . Examples of the network  150  may include any type of wired network, wireless network, or a combination of wired and wireless networks. A wireless network may be a wireless local area network (“WLAN”), a wireless wide area network (“WWAN”), or any other type of wireless network now known or later developed. Additionally, the network  150  may be or include the Internet, intranets, extranets, microwave networks, satellite communications, cellular systems, personal communication services (“PCS”), infrared communications, global area networks, or other suitable networks, etc., or any combination of two or more such networks. 
     Since the user  115  is needed to only enter the payment string  125   a  for making a payment to the merchant  110 , the overall transaction flow is effortless for completing the payment transaction. In existing payment transaction methods (i.e., not in accordance with the present disclosure), the user  115  is required to carry his physical payment card for purchasing an item from the merchant  110 , so that the user  115  can swipe the payment card into the POS terminal  125 , or user  115  is required to enter details such as payment card number, date of expiry, CVV details, etc., in case of online transaction. In contrast to existing payment transaction methods, by using the embodiments of the present disclosure, the user  115  is only required to enter the string  125   a  in the POS terminal  125  or on the online merchant interface, to process the payment transaction. Hence, the user  115  needs not to worry about keeping the payment cards with him so that theft related issues get eliminated in addition to faster transaction time, using various techniques of the present disclosure. Some non-exhaustive example embodiments of completing payment transactions using payment strings are described with reference to the following description, particularly with reference to  FIGS. 2 to 6 . 
       FIG. 2  illustrates an example representation  200  of a payment string  225  generated for facilitating a payment transaction, in accordance with an example embodiment of the present disclosure. As shown, the payment string  225  (hereinafter alternatively referred to as string  225 ) is exemplarily depicted as ‘0012151AZ2151’. The string  225  is an example of the string  125   a  as entered by the user  115  of  FIG. 1  at the facility  105 . In one embodiment, the string  225  comprises 3 unique parts, for example, a human generated password (HGP)  205  (see, 001), a chord  210  (see, 2151AZ) and a personal identification number (PIN)  215  (see, 2151). In an example embodiment, the HGP  205  is runtime generated dynamic password. The HGP  205  can be a predefined code based on a particular pattern, where the pattern can be set by a user (such as the user  115 ) by accessing an interface provided by the issuer sever  135 . In one embodiment, an HGP generation is facilitated by the issuer server  135  associated with the issuer bank of the user in which the user holds a payment account. Generation of the HGP is explained later with reference to  FIG. 6 . 
     The chord  210  is a six character long alpha-numeric chord that is uniquely generated for the payment card of user for completion of payment transaction using the string  225 . In one embodiment, the chord  210  is generated by the payment server  140  associated with the payment network  145 . The payment server  140  is configured to store the unique chord associated with each user in a mapping table. The mapping table further includes issuer account information of the user&#39;s payment card, where the issuer account information is mapped to the unique chord. The issuer account information is retrieved from the mapping table, when the string  225  is received by the payment server  140 . The mapping table is explained in detail with reference to  FIG. 5  later. 
     The PIN  215  is a four-digit identification code issued by the issuer bank of the user while registering for electronic payment transactions or while issuing the payment card to the user. For example, the PIN  215  may be issued for swipe based transactions, mobile banking, internet banking, payment string based transaction and the like. The PIN  215  is needed to be verified for authentication of the user&#39;s identity and association with the issuer bank to process the payment transaction. In an example embodiment, the payment server  140  is configured to verify the PIN  215 . Alternatively or additionally, the issuer server  135  is configured to verify the PIN  215 . As shown by a box  220 , all the three parts such as the HGP  205 , the chord  210  and the PIN  215  are combined/bundled together to form the unique payment string  225 . The verification of the payment string  225  is performed by a combination of servers such as the payment server  140  and the issuer server  135 , and is explained hereinafter. 
       FIG. 3  represents a sequence flow diagram  300  representing a completion of a payment transaction using a payment string (e.g., the payment string  225  or  125   a ) at a POS terminal  125 , in accordance with an example embodiment. 
     As a user (e.g., the user  115 ) purchases a product from a merchant (e.g., the merchant  110 ) and reaches the POS terminal for making the payment transaction, the POS terminal prompts a user interface (UI) asking the user to enter unique payment string for making the payment transaction. 
     At  305 , the user enters a payment string using a POS terminal (e.g., the POS terminal  125 ). The user or the merchant (e.g., the merchant  110 ) can enter a transaction amount (e.g., $50) to be paid by the user for performing the financial transaction using the POS terminal  125 . The transaction amount may be determined by scanning products that are bought at the facility  105 . Alternatively, the mobile phone of the user may be equipped with some suitable applications to scan the bar code or price tag so as to be able to decide upon the transaction amount. In an example, the POS terminal may have a POS ID and is associated with an acquirer account of the merchant. In some alternate embodiments, the user may use an online merchant interface such as a merchant website or a third party website offering merchant&#39;s products or services. In these embodiments, the user may be asked to enter the unique payment string in a form field provided in the online merchant interface to initiate the payment transaction. 
     At  310 , the payment string and the transaction amount i.e., the payment transaction request is sent from the merchant facility to the acquirer server  130  for further processing. As described with reference to  FIG. 2 , the string can have three parts i.e., HGP  205 , the chord  210  and the PIN  215 . Without departing from the scope of present disclosure, the string may include only two parts such as the HGP and the chord, or the chord  210  and the PIN  215  and still the payment transaction can be facilitated. 
     At  315 , the acquirer server  130  sends the payment transaction request to the payment server  140  for verification of the payment string. The acquirer server  130  also determines the acquirer account of the merchant and sends the acquirer account details to the payment server  140 . 
     At  320 , the payment server parses the payment string to retrieve the HGP, the chord, and the PIN parts from the payment string. One or more dedicated algorithms may be utilized by the payment server  140  to retrieve the chord from the payment string, as described further with reference to  FIG. 5 . 
     At  325 , the payment string is validated by the payment server  140 , based on at least one rule set. Examples of the rule set may include a format of the payment string, an order of parts of the payment string, and overall length of the payment string, or length of individual parts of the payment string. In an embodiment, the payment server  140  only validates the chord part of the payment string based on the rule sets. For instance, the chord is validated based on rule sets such as predefined formats set for the chord. In an example, length (i.e., number of characters) and format (such as allowable characters used for the chord) of the chord is checked by the payment server  140 . In some embodiments the operation  320  may be performed after the step  325 . 
     The payment server  140  includes a mapping table stored in its database. The mapping table includes one or more lookup tables configured to provide required information. One example representation of the mapping table is shown in  FIG. 5 , where the mapping table includes a lookup table 1, which is used by the payment server  140  to retrieve hashed value associated with the chord. The hashed values are generated by hash algorithms stored in the payment server  140 . 
     At  330 , upon successful validation of the chord, the payment server  140  is configured to re-parse the chord to retrieve the user account information associated with the user. For example, the payment server  140  may utilize a lookup table-2 of the mapping table that includes the hashed values associated with the chord and corresponding issuer account information of the user. Some non-exhaustive examples of the issuer account information include bank identifier code (BIC), account number, payment card number and the like. 
     At  335 , the payment server  140  verifies the PIN part of the payment string. as explained earlier, the PIN is issued by the issuer bank of the user for authentication the payment transactions. If the user has entered an incorrect PIN, the transaction may fail and the user and the merchant may be notified for the same. The user may also be requested to re-enter the payment string at the POS terminal  125 . Similarly, if the chord part of the string is not validated, the user may be requested to re-enter the string to process the payment transaction further. 
     At  340 , the payment server sends the retrieved HGP, the transaction amount and the retrieved issuer account information to the issuer server  135 . At  345 , the issuer server  135  validates the HGP of the user from an HGP database stored therein. The HGP can be generated and modified from time to time using various communication channels of the issuer such as using net banking, by physically visiting the bank, by calling the customer care of the bank or using an ATM. This is explained later in detail with reference to  FIG. 6 . 
     At  350 , the issuer server  135  verifies the balance/funds in the payment account of the user (i.e., issuer account) against the received transaction amount. Upon verifying enough funds present in the issuer account, the issuer server  135  may debit the transaction amount from the issuer account of the user. (see,  355 ). 
     At  360 , the issuer server  135  notifies the acquirer server  130  about the debiting of the transaction amount from the issuer account. More specifically, using the payment network  145  (i.e., the payment server  140 ), the issuer server  135  communicates with the acquirer server  130  after determining at operation  350 , whether the user&#39;s account is in good standing and whether the purchase is covered by the user&#39;s available credit line or account balance. Based on these determinations, the available credit line or available balance of the user&#39;s account is decreased at operation  355  and thereafter the acquirer server  130  is notified about the debiting. 
     At  365 , the acquirer server  130  credits the transaction amount in the merchant account. Thereafter, the acquirer server  130  sends the transaction status to the POS terminal  125  or to the online merchant interface (in case of user using online payment to the merchant) at  370 . The transaction status may include successful, failure or pending. For example, If the HGP is not validated at operation  345 , the issuer server  135  may notify the payment server  140  and thereby to the acquirer server  130  of the same. The acquirer server  130  may notify the failed transaction status to the POS terminal  125  for display to the user. The merchant may request the user to re-enter the payment string as a reattempt to process the payment transaction using the payment string. The payment transaction completes at operation  375 . In this manner, the primary benefits of the present disclosure are to achieve a deep fall in frauds related to payment card based payment transactions, security against theft and simplicity using cashless and card-less transactions. 
       FIG. 4  represents a sequence flow diagram  400  representing a completion of a payment transaction using a payment string  225 /a payment string  125   a  at a POS terminal  125 , in accordance with another example embodiment. At  405 , the POS terminal  125  receives the payment string from the user and the transaction amount from the user or the merchant. At  410 , the payment transaction request is sent to the acquirer server  130 . At  415 , the payment transaction request is received by the payment server  140  from the acquirer server  130 . The payment server  140  is configured to verify and validate the payment string received from the acquirer server  130 . At  420 , the payment server  140  parses the string to retrieve its parts such as the HGP, the chord and the PIN. The retrieved chord is validated by the payment server  140  using the at least one rule set such as  404  pay chord standard. At  430 , upon successful validation of the chord, the payment server  140  retrieves associated issuer account information from the mapping table accessible to the payment server  140 . 
     The retrieved issuer account information, the PIN, the HGP and the transaction amount are sent to the issuer server  135  at operation  435 . At  440 , the issuer server  135  is configured to validate the HGP part of the string associated with the user from a corresponding HGP database. At  445 , the issuer server verifies the PIN part of the string. Upon successful verification of the PIN, at  445 , the issuer server  135  verifies whether the user&#39;s payment account (i.e., the issuer account) is in good standing and whether the prospective purchase is covered by the user&#39;s available credit line or account balance. If the account holds enough balance amount, the issuer server  135  debits the exact number of transaction amount from the account at operation  455 . At  460 , the issuer server  135  notifies the acquirer server  130  about the debiting of the transaction amount from the issuer account using the payment network  145 . At  465 , the acquirer server  130  credits the debited transaction amount to the merchant account. At  470 , the acquirer server  130  notifies the POS terminal  125  (or message is displayed on the online merchant interface) and thereby the merchant and the user of the transaction status. At  475 , the payment transaction completes. 
       FIG. 5  represents a simplified schematic representation  500  including payment strings and a mapping table stored in the payment server  140  for verifying payment strings for completion of payment transactions, in accordance with an example embodiment. The representation  500  includes some examples of the payment strings (see,  505 ), which is parsed to retrieve the corresponding chord value. The mapping table can be represented by a combination of two tables such as a lookup table-1 (see,  550   a ) and a lookup table-2 (see,  550   b ). The columns of the table  550   a  represent titles a chord  510 , a key to re-hash value  515  and a hashed value  520 . The rows of the table  550   a  represent corresponding information associated with the columns. For example, row  560   a  represents a chord ‘2151AZ’, key to re-hash value ‘Key 1’ and a hashed value ‘xxxx1’. The table  550   a  includes details of a plurality of chords (predefined length alphanumeric codes) and associated hashed values. For instance, each row (e.g., the row  560   a , the row  560   b , through the row  560   n ) represents a chord, a key to re-hash value and a hashed value for the chord. 
     As explained with reference to operation  350  of the flow diagram  300  of  FIG. 3 , the payment server  140  is configured to parse the payment string to retrieve unique parts of the string. For example, the payment server  140  is configured to retrieve chord ‘3551AZ’ from the payment string ‘0213351AZ1111’, and the retrieved chord is matched with the chords  510  stored in the table  550   a . Each chord is assigned a key such as ‘Key 2’ and a corresponding hashed value is generated such as ‘3456vu’ as represented by the row  560   b . In one embodiment, the key is used to re-hash the hashed value for retrieving corresponding issuer account information from the lookup table-2 (see,  550   b ). For example, the hashed value ‘3456vu’ is re-parsed by the payment server  140  using one or more hashing algorithms to further retrieve the issuer account information. 
     The lookup table-2 (see,  550   b ) includes columns with titles a hashed value  520 , a bank identifier code (BIC)  525  and account/card number  530 . The table  550   b  includes details of a plurality of issuer account information associated with a plurality of users. For instance, each row such as the rows  580   a ,  580   b  through  580   n  represent corresponding issuer account information associated with the hashed value. For example, row  580   b  represents hashed value ‘3456vu’, corresponding BIC ‘AAAAA125’ and corresponding account number ‘5178987325’. As explained with reference to operation  340  of the flow diagram  300  of  FIG. 3 , the account number ‘5178987325’ and BIC ‘AAAAA125’ (i.e., the issuer account information) retrieved from the chord ‘3551AZ’ (retrieved from the payment string ‘0213351AZ1111’), is sent to the issuer server  135  for processing the payment transaction. The issuer server  135  identifies the issuer bank using BIC ‘AAAAA125’ and verifies the funds in the issuer account of the user using the account number ‘5178987325’, as explained with reference to operation  350  of the flow diagram  300  of  FIG. 3 . 
       FIG. 6  represents a simplified block diagram representation  600  of generation of a Human Generated Password (HGP) by a user, in accordance with an example embodiment. More specifically, the representation  600  depicts two aspects related to HGP, one for a new user enrollment for a user  605  and another for update/change in the HGP for an existing user  610 . An issuer server  135  is shown to include (or has access of) a database such as the HGP database  615  to maintain the HGP records. The issuer server  135  can be reached by the users  605 ,  610  via one or more communication channels such as an ATM  625 , a physical bank visit (see,  630 ), an internet banking  635  and a helpline call service  640 . The users  605 ,  610  can utilize any of the communication channels to generate a new HGP or update the existing HGP, respectively. For example, the user  605  can physically visit the bank premises for registering a new HGP for utilizing the payment string based payment transactions. As another example, the user  610  can modify the HGP using internet banking applications or websites provided linked to the issuer server  135  on his/her personal electronic device. As yet another example, the users  605 ,  610  can update/generate the HGP using the ATM  625  or by utilizing the helpline call service  640 . 
     In one embodiment, the HGP database  615  stores each HGP associated with each enrolled user. Further, the HGP database  615  updates the modified HGPs in real time or periodically as required. The HGP is a runtime generated dynamic password. The user may be enabled to generate HGP based on predefined patterns. For example, the user may set the HGP based on days of a week i.e., 001, 002, 003, 004, 005, 006 and 007. Alternatively, the user can set/modify the HGP based on days of month i.e., 001 . . . 030, 031. Yet alternatively, the user may define a pattern of combination of days of month and week i.e., 101, 002, 012 etc. The user may be enabled to change the HGP daily or even multiple times a day. In an example embodiment, the user may be requested to select a type of question provided by the issuer server  135  and depending on the complexity of the question, the issuer may generate an HGP with matching level of complexity for the user to use while making payment using payment string. In an example, if the user has selected the HGP as per the day of the week, the user will enter “001” as part of the payment string, when making a payment transaction on any Monday. Similarly, the user will enter “002” as part of the payment string, when making a payment transaction on any Tuesday, and so on. 
       FIG. 7  illustrates a flow diagram of a method  700  for carrying out payment transaction using payment string, in accordance with an example embodiment. More specifically, a method  700  for facilitating a payment transaction from an issuer account of a user to an acquirer account of a merchant without swiping or entering card details of a payment card at a merchant interface of the merchant is disclosed. The method  700  depicted in the flow diagram may be executed by, for example, the at least one server system such as the acquirer server  130 , the issuer server  135  and the payment server  140  explained with reference to  FIG. 1 . Operations of the flow diagram  700 , and combinations of operation in the flow diagram  700 , may be implemented by, for example, hardware, firmware, a processor, circuitry and/or a different device associated with the execution of software that includes one or more computer program instructions. The operations of the method  700  are described herein with help of the server systems  130 ,  135  or  140 . It is noted that the operations of the method  700  can be described and/or practiced by using a system other than these server systems. The method  700  starts at operation  702 . 
     At  702 , the method  700  includes receiving, by a server system (e.g., the acquirer server  130 ) associated with a payment network, a payment transaction request. The payment transaction request includes at least a payment string (e.g., the payment string  125   a ) uniquely associated with the payment card linked with the issuer account and a transaction amount to be paid to the merchant. 
     At  704 , the method  700  includes, verifying a validity of the payment string based on at least one rule set. For example, the payment server  140  may be configured to verify the validity of the payment string by checking format of the payment string received as part of the payment transaction request. 
     At  706 , the method  700  includes retrieving issuer account information associated with the issuer account based on at least a part of the payment string upon successful validation of the payment string. In one embodiment, the issuer account information may be retrieved by matching a predefined length alphanumeric code (chord  510 ) in a mapping table from a database. The predefined length alphanumeric code is a part of the payment string. 
     At  708 , the method  700  includes facilitating the payment transaction based at least on the retrieved issuer account information from the issuer account to the acquirer account. It should be appreciated that the operations  702 - 708  are performed without the need of the user to carry his payment cards, cash, the mobile phone or the payment card details at the merchant facility. Since the user is only required to enter the unique string, and the server systems are required to validate only a part of the payment string separately and in parallel, the overall time to complete the payment transaction reduces adequately. Such arrangement further leads to more secure payment transactions and better user experience to the user, as he/she is given the flexibility of not remembering to carry his wallet all the time. 
       FIG. 8  is a simplified block diagram of a server system  800  used for payment transaction using payment string, in accordance with one embodiment of the present disclosure. The server system  800  is an example of a server system that is a part of the payment network  145 . Examples of the server system  800  includes, but not limited to, the acquirer server  130 , the issuer server  135  and the payment server  140 . The server system  800  includes a computer system  805  and a database  810 . 
     The computer system  805  includes at least one processor  815  for executing instructions. Instructions may be stored in, for example, but not limited to, a memory  820 . The processor  815  may include one or more processing units (e.g., in a multi-core configuration). 
     The processor  815  is operatively coupled to a communication interface  825  such that computer system  805  is capable of communicating with a remote device such as a merchant device  840  (e.g., the POS terminal  125 ) or a user device  835  or communicating with any entity within the payment network  145 . For example, the communication interface  825  may receive the payment transaction request such as the payment string uniquely associated with a user and a transaction amount from a merchant device  840 , via the Internet. 
     The processor  815  may also be operatively coupled to the database  810 . The database  810  is any computer-operated hardware suitable for storing and/or retrieving data, such as, but not limited to, transaction data generated as part of sales activities conducted over the bankcard network including data relating to merchants, account holders or customers, and purchases. The database  810  may also store information related to a plurality of user&#39;s payment accounts. Each user account data includes at least one of a user name, a user address, an account number, PIN, HGP, and other account identifiers. The database  810  may also store merchant data including a merchant identifier that identifies each merchant registered to use the payment network, and instructions for settling transactions including merchant bank account information (e.g., a plurality of payment accounts related to POS terminals associated with merchants). The database  810  may further include a mapping table composed of one or more lookup tables which include payment strings and associated issuer account information. The database  810  may include multiple storage units such as hard disks and/or solid-state disks in a redundant array of inexpensive disks (RAID) configuration. The database  810  may include a storage area network (SAN) and/or a network attached storage (NAS) system. 
     In some embodiments, the database  810  is integrated within computer system  805 . For example, computer system  805  may include one or more hard disk drives as database  810 . In other embodiments, database  810  is external to computer system  805  and may be accessed by the computer system  805  using a storage interface  830 . The storage interface  830  is any component capable of providing the processor  815  with access to the database  810 . The storage interface  830  may include, for example, an Advanced Technology Attachment (ATA) adapter, a Serial ATA (SATA) adapter, a Small Computer System Interface (SCSI) adapter, a RAID controller, a SAN adapter, a network adapter, and/or any component providing processor  815  with access to the database  810 . 
     The processor  815  is configured to perform verification of the payment string and the transaction amount by communicating with the database  810 . For instance, the processor  815  is configured to facilitate the authentication by validating the chord part of the payment string from corresponding information stored in the database  810 . For example, the processor  815  can verify the payment card number, account number, PIN, HGP etc. by accessing respective information from the database  810 . The processor  815  is further configured to approve the transaction amount by verifying against the available balance in the issuer account of the user, as stored in the database  810 . Thereafter, the processor  815  is configured to complete the payment transaction of the transaction amount from issuer account to the acquirer account. The processor  815  is configured to notify the user device  835  and merchant device  840  of the transaction status via the communication interface  825 . 
       FIG. 9  is a simplified block diagram of a POS terminal  900  used for payment transaction using payment string, in accordance with one embodiment of the present disclosure. The POS terminal  900  as explained herein is only one example of the merchant device  840 . In various embodiments, the merchant device  840  can be a merchant mobile phone, a kiosk, a PDA, a merchant facilitated e-commerce website interface running on a computing device and the like. The POS terminal  900  is an example of the POS terminal  125  of  FIG. 1  in terms of functionalities and features. The POS terminal  900  includes at least one processor  905  communicably coupled to a database  910 , an Input/Output (I/O) interface  915 , a communication interface  920 , a memory  925  and an HGP module  940 . The components of the POS terminal  900  provided herein may not be exhaustive, and that the POS terminal  900  may include more or fewer components than that of depicted in  FIG. 9 . Further, two or more components may be embodied in one single component, and/or one component may be configured using multiple sub-components to achieve the desired functionalities. Some components of the POS terminal  900  may be configured using hardware elements, software elements, firmware elements and/or a combination thereof. 
     The I/O interface  915  is configured to receive inputs from and provide outputs to the end-user (i.e., the merchant and/or the customer) of the POS terminal  900 . For instance, the I/O module  915  may include at least one input interface and/or at least one output interface. Examples of the input interface may include, but are not limited to, a keyboard, a mouse, a joystick, a keypad, a touch screen, soft keys, a microphone, and the like. Examples of the output interface may include, but are not limited to, a UI display (such as a light emitting diode display, a thin-film transistor (TFT) display, a liquid crystal display, an active-matrix organic light-emitting diode (AMOLED) display, etc.), a speaker, a ringer, a vibrator, and the like. 
     The memory  925  can be any type of storage accessible to the processor  905 . For example, the memory  925  may include volatile or non-volatile memories, or a combination thereof. In some non-limiting examples, the memory  925  can be four to sixty four MegaBytes (MB) of Dynamic Random Access Memory (“DRAM”) or Static Random Access Memory (“SRAM”). In addition, some examples may include supplementary flash memory installed via a PCMCIA slot. 
     The database  910  is capable of storing and/or retrieving data, such as, but not limited to, smart card insertions, user/customer information, merchant information, payment strings uniquely associated with each user, card swipes, touch-screen key depressions, keypad key depressions, number of dots printed by the slip and roll printers, check read errors, and the like. Such information can be accessed by the processor  905  using the communication interface  920  to determine potential future failures and the like. 
     The POS terminal  900  is capable of communicating with one or more POS peripheral devices such as the POS peripheral deice  935  and external server system such as an acquirer server  930  (an example of the acquirer server  130  of  FIG. 1 ) via the communication interface  920  over a communication network such as the network  150  of  FIG. 1 . The POS peripheral device  935  can provide functionality, which is used by a consumer at a merchant facility, such as PIN entry, payment string entry, clear text entry, signature capture, and the like. Some non-exhaustive examples of the peripheral device  935  include barcode scanner, cash drawer, magnetic stripe reader, receipt printer, PIN pad, signature capture device, touchscreen, keyboard, portable data terminal, card reader, customer pole display and the like. In some embodiments, the POS terminal  900  may be mounted near a cash register at a check-out counter in merchant facility, while the POS peripheral device  935  may be mounted on the check-out counter such that it is accessible to the users. In this way, both the merchant and the user/customer can interact with similar devices to process the payment transaction. 
     The communication interface  920  is further configured to cause display of user interfaces on the POS terminal  900 . For example, using a corresponding UI, the communication interface  920  may display a new payment option such as the payment using based payment transaction. The user may select the option displayed on the POS terminal  900  to initiate the payment transaction using the payment string. In one embodiment, the communication interface  220  includes a transceiver for wirelessly communicating information to, or receiving information from, the acquirer server  930  or other suitable display device, and/or another type of remote processing device. In another embodiment, the communication interface  920  is capable of facilitating operative communication with the remote devices and a cloud server using Application Program Interface (API) calls. The communication may be achieved over a communication network, such as the network  150 . 
     The processor  905  is capable of sending the payment transaction request received from the end-user via the communication interface  920  to the acquirer server  930  for processing the payment transaction. For example, the processor  905  is configured to receive the payment string and the transaction amount entered by the end-user using the Uls. The processor  905  can access the database  925  to retrieve the user information and merchant information that are required to be sent along with the payment transaction request to the acquirer server  930 . 
     Additionally, the POS terminal  900  can include an operating system and various software applications that can provide various functionality to the POS terminal  900 . For example, in some embodiments, the POS terminal  900  is addressable with an Internet protocol and includes a browser application. In such embodiments, the processor  905  includes software adapted to support such functionality. In some embodiments, the processor  905  executes software to support network management. In particular, this capacity allows software to be downloaded to a plurality of such systems to provide new applications such as applications for enabling payment string based payment transactions using POS terminals and/or updates to existing applications. The operating system and software application upgrades are distributed and maintained through communication to the POS terminal  900  over the communication network  150 . For example, existing POS terminals may be adapted to download a new HGP module such as the HGP module  940  of the POS terminal  900  that supports new functionalities for enabling payment string based payment transactions. Using the program instructions stored in the HGP module  940 , the processor  905 , may be configured to facilitate the end user to pay using the payment string, where the entered payment string is communicated to the acquirer server  1100 . 
       FIG. 10  is a simplified block diagram of an issuer server  1000  for payment transaction using payment string, in accordance with one embodiment of the present disclosure. The issuer server  1000  is an example of the issuer server  135  of  FIG. 1 , or may be embodied in the issuer server  135 . The issuer server  1000  is associated with an issuer bank/issuer, in which a user may have an account, which provides a payment string based electronic payment transaction facility. The issuer server  1000  includes a processing module  1005  operatively coupled to a storage module  1010 , a verification module  1015 , an HGP generation module  1020 , and a communication module  1025 . The components of the issuer server  1000  provided herein may not be exhaustive, and that the issuer server  1000  may include more or fewer components than that of depicted in  FIG. 10 . Further, two or more components may be embodied in one single component, and/or one component may be configured using multiple sub-components to achieve the desired functionalities. Some components of the issuer server  1000  may be configured using hardware elements, software elements, firmware elements and/or a combination thereof. 
     The storage module  1010  is configured to store machine executable instructions to be accessed by the processing module  1005 . Additionally, the storage module  1010  stores information related to, contact information of the user, bank account number, BICs, payment card details, HGP and any updates in the HGP (such as stored in the HGP database  615  of  FIG. 6 ), internet banking information, PIN, mobile personal identification number (MPIN) for mobile banking and the like. This information is retrieved by the processing module  1005  for cross-verification during payment transactions. 
     The HGP generation module  1020  is configured to facilitate a user to register/enroll for payment string based payment transactions by generating an HGP. The HGP generation module  1020  includes logics to pre-define one or more patterns based on which the user can generate/update the HGP from time to time as explained with reference  FIG. 6  earlier. The HGPs generated by the HGP generation module  1020  are stored in the storage module  1010  for later retrieval by the processing module  1005  for verification purposes. 
     The processing module  1005 , in conjunction with the verification module  1015 , is configured to verify the HGP (e.g., whether the three-digit password is set as per the predefined pattern), the PIN (e.g., whether the four-digit numeric code matches the PIN issued by the issuer), the sufficient funds in the issuer account, payment card details and the like. Upon successful verification only, the payment transaction is processed further by the processing module  1005  by debiting the transaction amount from the issuer account of the user. The processing module  1005  is further configured to communicate with one or more remote devices such as the remote device  1030  using the communication module  1025  over a network such as the network  150  or the payment network  145  of  FIG. 1 . The examples of the remote device  1030  include, the merchant device  840 , the user device  835 , the payment server  140 , the acquirer server  130 , other computing systems of issuer and payment network  145  and the like. The communication module  1025  is capable of facilitating such operative communication with the remote devices and cloud servers using API (Application Program Interface) calls. 
       FIG. 11  is a simplified block diagram of an acquirer server  1100  used for payment transaction using payment string, in accordance with one embodiment of the present disclosure. The acquirer server  1100  is associated with the acquirer bank of a merchant where the merchant has established an account to accept payment using the payment string. The acquirer server  1100  is an example of the acquirer server  130  of  FIG. 1 , or may be embodied in the acquirer server  130 . Further, the acquirer server  1100  is configured to facilitate payment string based payment transaction with the issuer server  1000  using the payment network  145  of  FIG. 1 . The acquirer server  1100  includes a processing module  1105  communicably coupled to a merchant database  1110  and a communication module  1115 . The components of the acquirer server  1100  provided herein may not be exhaustive, and the acquirer server  1100  may include more or fewer components than that of depicted in  FIG. 11 . Further, two or more components may be embodied in one single component, and/or one component may be configured using multiple sub-components to achieve the desired functionalities. Some components of the acquirer server  1100  may be configured using hardware elements, software elements, firmware elements and/or a combination thereof. 
     The merchant database  1110  includes data related to merchant, such as, but not limited to, a merchant primary account number (PAN), a merchant name, a merchant category code (MCC), a merchant city, a merchant postal code, a merchant brand name, a merchant ID and the like. The processing module  1105  is configured to use the merchant ID to identify the merchant during the normal processing of payment transactions, adjustments, chargebacks, end-of-month fees and so forth. The merchant ID is different than other merchant account numbers, particularly those that identify merchants to the equipment (e.g., the POS terminals or any other merchant electronic devices) they use for processing transactions. A merchant with a single merchant processing account number may use several terminals at one location, resulting in one merchant ID and several terminal identification numbers (TIDs). The processing module  1105  may be configured to store and update such merchant information in the merchant database  1110  for later retrieval. 
     In an embodiment, the communication module  1115  is capable of facilitating operative communication with the remote device  1120  (e.g., the POS terminal  900 , the issuer server  1000 , the merchant device  840  and/or the payment server  140 ) using API calls. The communication may be achieved over a communication network, such as the network  150 . For example, the processing module  1105  may receive the payment string and the transaction amount from the POS terminal  900  using the communication module  1115 . Further, the processing module  1105  is configured to receive the debited transaction amount from the payment server  140  or the issuer server  135  (or the issuer server  1000 ) using the communication module  1115 . Thereafter, the processing module  1105  may retrieve merchant PAN from the database  1110  to credit the transaction amount in the acquirer account of the merchant. Further, the processing module  1105  may be configured to send the transaction status to the POS terminal  900  of the merchant. 
       FIG. 12  is a simplified block diagram of a payment server  1200  used for payment transaction using payment string, in accordance with one embodiment of the present disclosure. The payment server  1200  may correspond to the payment server  140  of  FIG. 1 . As explained with reference to  FIG. 1 , the payment server  140  is associated with a payment network  145 . The payment network  145  may be used by issuer server  1000  and acquirer server  1100  as a payment interchange network. Examples of payment interchange network include, but not limited to, Mastercard® payment system interchange network. The payment server  1200  includes a processing system  1205  configured to extract programming instructions from a memory  1210  to provide various features of the present disclosure. The components of the payment server  1200  provided herein may not be exhaustive, and that the payment server  1200  may include more or fewer components than that of depicted in  FIG. 12 . Further, two or more components may be embodied in one single component, and/or one component may be configured using multiple sub-components to achieve the desired functionalities. Some components of the payment server  1200  may be configured using hardware elements, software elements, firmware elements and/or a combination thereof. 
     Via a communication interface  1220 , the processing system  1205  receives a payment string and transaction amount from a remote device  1235  such as the POS terminal  900  or the acquirer server  1100 . The communication may be achieved through API calls, without loss of generality. A parsing module  1225  is operatively coupled to the processing system  1205 . The parsing module  1225  includes one or more parsing algorithms capable of parsing the payment string and thereby extracting the chord. The chord retrieved from the payment string is validated by the processing system  1205  using a validation module  1230  that includes a predefined rule set to be used for validation purposes. Without loss of generality, a mapping table  1240  stored in a database  1215  includes a lookup table-1 (see,  1240   a ) and a lookup table-2 (see,  1240   b ) to be utilized by the processing system  1205  to retrieve issuer account information. As explained with reference to  FIG. 5 , the processing system  1205  is configured to include one or more hashing algorithms to re-parse the chord to generate hashed values. The hashed values are stored in the mapping table  1240  and are associated with issuer account information of each user. Apart from the mapping table  1240 , the database  1215  stores the PIN, the HGP, the transaction amount, acquirer account information, transaction records, merchant account information, and the like. Upon successful validation of the PIN and the chord, the processing system  1205  sends the HGP to the issuer server  1000  for verification and completion of the payment transaction via the communication interface  1220 . 
       FIG. 13  shows simplified block diagram of a user device  1300  for example a mobile phone or a desktop computer capable of implementing the various embodiments of the present disclosure. For example, the user device  1300  may correspond to the user device  835  of  FIG. 8 . The user device  1300  is depicted to include one or more applications  1306 . 
     It should be understood that the user device  1300  as illustrated and hereinafter described is merely illustrative of one type of device and should not be taken to limit the scope of the embodiments. As such, it should be appreciated that at least some of the components described below in connection with that the user device  1300  may be optional and thus in an example embodiment may include more, less or different components than those described in connection with the example embodiment of the  FIG. 13 . As such, among other examples, the user device  1300  could be any of a mobile electronic device, for example, cellular phones, tablet computers, laptops, mobile computers, personal digital assistants (PDAs), mobile televisions, mobile digital assistants, or any combination of the aforementioned, and other types of communication or multimedia devices. 
     The illustrated user device  1300  includes a controller or a processor  1302  (e.g., a signal processor, microprocessor, ASIC, or other control and processing logic circuitry) for performing such tasks as signal coding, data processing, image processing, input/output processing, power control, and/or other functions. An operating system  1304  controls the allocation and usage of the components of the user device  1300  and support for one or more payment transaction applications programs (see, applications  1306 ), that implements one or more of the innovative features described herein. In addition, the applications  1306  may include common mobile computing applications (e.g., telephony applications, email applications, calendars, contact managers, web browsers, messaging applications) or any other computing application. 
     The illustrated user device  1300  includes one or more memory components, for example, a non-removable memory  1308  and/or removable memory  1310 . The non-removable memory  1308  and/or removable memory  1310  may be collectively known as database in an embodiment. The non-removable memory  1308  can include RAM, ROM, flash memory, a hard disk, or other well-known memory storage technologies. The removable memory  1310  can include flash memory, smart cards, or a Subscriber Identity Module (SIM). The one or more memory components can be used for storing data and/or code for running the operating system  1304  and the applications  1306 . The user device  1300  may further include a user identity module (UIM)  1312 . The UIM  1312  may be a memory device having a processor built in. The UIM  1312  may include, for example, a subscriber identity module (SIM), a universal integrated circuit card (UICC), a universal subscriber identity module (USIM), a removable user identity module (R-UIM), or any other smart card. The UIM  1312  typically stores information elements related to a mobile subscriber. The UIM  1312  in form of the SIM card is well known in Global System for Mobile Communications (GSM) communication systems, Code Division Multiple Access (CDMA) systems, or with third-generation (3G) wireless communication protocols such as Universal Mobile Telecommunications System (UMTS), CDMA9000, wideband CDMA (WCDMA) and time division-synchronous CDMA (TD-SCDMA), or with fourth-generation (4G) wireless communication protocols such as LTE (Long-Term Evolution). 
     The user device  1300  can support one or more input devices  1320  and one or more output devices  1330 . Examples of the input devices  1320  may include, but are not limited to, a touch screen/a display screen  1322  (e.g., capable of capturing finger tap inputs, finger gesture inputs, multi-finger tap inputs, multi-finger gesture inputs, or keystroke inputs from a virtual keyboard or keypad), a microphone  1324  (e.g., capable of capturing voice input), a camera module  1326  (e.g., capable of capturing still picture images and/or video images) and a physical keyboard  1328 . Examples of the output devices  1330  may include, but are not limited to a speaker  1332  and a display  1334 . Other possible output devices can include piezoelectric or other haptic output devices. Some devices can serve more than one input/output function. For example, the touch screen  1322  and the display  1334  can be combined into a single input/output device. 
     A wireless modem  1340  can be coupled to one or more antennas (not shown in the  FIG. 13 ) and can support two-way communications between the processor  1302  and external devices, as is well understood in the art. The wireless modem  1340  is shown generically and can include, for example, a cellular modem  1342  for communicating at long range with the mobile communication network, a Wi-Fi compatible modem  1344  for communicating at short range with an external Bluetooth-equipped device or a local wireless data network or router, and/or a Bluetooth-compatible modem  1346 . The wireless modem  1340  is typically configured for communication with one or more cellular networks, such as a GSM network for data and voice communications within a single cellular network, between cellular networks, or between the user device  1300  and a public switched telephone network (PSTN). 
     The user device  1300  can further include one or more input/output ports  1350 , a power supply  1352 , one or more sensors  1354  for example, an accelerometer, a gyroscope, a compass, or an infrared proximity sensor for detecting the orientation or motion of the user device  1300  and biometric sensors for scanning biometric identity of an authorized user, a transceiver  1356  (for wirelessly transmitting analog or digital signals) and/or a physical connector  1360 , which can be a USB port, IEEE 1294 (FireWire) port, and/or RS-232 port. The illustrated components are not required or all-inclusive, as any of the components shown can be deleted and other components can be added. 
     The disclosed methods with reference to  FIGS. 3 and 4 , or one or more operations of the flow diagram  700  may be implemented using software including computer-executable instructions stored on one or more computer-readable media (e.g., non-transitory computer-readable media, such as one or more optical media discs, volatile memory components (e.g., DRAM or SRAM), or nonvolatile memory or storage components (e.g., hard drives or solid-state nonvolatile memory components, such as Flash memory components) and executed on a computer (e.g., any suitable computer, such as a laptop computer, net book, Web book, tablet computing device, smart phone, or other mobile computing device). Such software may be executed, for example, on a single local computer or in a network environment (e.g., via the Internet, a wide-area network, a local-area network, a remote web-based server, a client-server network (such as a cloud computing network), or other such network) using one or more network computers. Additionally, any of the intermediate or final data created and used during implementation of the disclosed methods or systems may also be stored on one or more computer-readable media (e.g., non-transitory computer-readable media) and are considered to be within the scope of the disclosed technology. Furthermore, any of the software-based embodiments may be uploaded, downloaded, or remotely accessed through a suitable communication means. Such suitable communication means include, for example, the Internet, the World Wide Web, an intranet, software applications, cable (including fiber optic cable), magnetic communications, electromagnetic communications (including RF, microwave, and infrared communications), electronic communications, or other such communication means. 
     Although the invention has been described with reference to specific exemplary embodiments, it is noted that various modifications and changes may be made to these embodiments without departing from the broad spirit and scope of the invention. For example, the various operations, blocks, etc., described herein may be enabled and operated using hardware circuitry (for example, complementary metal oxide semiconductor (CMOS) based logic circuitry), firmware, software and/or any combination of hardware, firmware, and/or software (for example, embodied in a machine-readable medium). For example, the apparatuses and methods may be embodied using transistors, logic gates, and electrical circuits (for example, application specific integrated circuit (ASIC) circuitry and/or in Digital Signal Processor (DSP) circuitry). 
     Particularly, the server systems  130 ,  135  and  140  its various components such as the computer system  805  and the database  810  may be enabled using software and/or using transistors, logic gates, and electrical circuits (for example, integrated circuit circuitry such as ASIC circuitry). Various embodiments of the invention may include one or more computer programs stored or otherwise embodied on a computer-readable medium, wherein the computer programs are configured to cause a processor or computer to perform one or more operations. A computer-readable medium storing, embodying, or encoded with a computer program, or similar language, may be embodied as a tangible data storage device storing one or more software programs that are configured to cause a processor or computer to perform one or more operations. Such operations may be, for example, any of the steps or operations described herein. In some embodiments, the computer programs may be stored and provided to a computer using any type of non-transitory computer readable media. Non-transitory computer readable media include any type of tangible storage media. Examples of non-transitory computer readable media include magnetic storage media (such as floppy disks, magnetic tapes, hard disk drives, etc.), optical magnetic storage media (e.g. magneto-optical disks), CD-ROM (compact disc read only memory), CD-R (compact disc recordable), CD-R/W (compact disc rewritable), DVD (Digital Versatile Disc), BD (BLU-RAY® Disc), and semiconductor memories (such as mask ROM, PROM (programmable ROM), EPROM (erasable PROM), flash memory, RAM (random access memory), etc.). Additionally, a tangible data storage device may be embodied as one or more volatile memory devices, one or more non-volatile memory devices, and/or a combination of one or more volatile memory devices and non-volatile memory devices. In some embodiments, the computer programs may be provided to a computer using any type of transitory computer readable media. Examples of transitory computer readable media include electric signals, optical signals, and electromagnetic waves. Transitory computer readable media can provide the program to a computer via a wired communication line (e.g., electric wires, and optical fibers) or a wireless communication line. 
     Various embodiments of the invention, as discussed above, may be practiced with steps and/or operations in a different order, and/or with hardware elements in configurations, which are different than those which, are disclosed. Therefore, although the invention has been described based upon these exemplary embodiments, it is noted that certain modifications, variations, and alternative constructions may be apparent and well within the spirit and scope of the invention. 
     Although various exemplary embodiments of the invention are described herein in a language specific to structural features and/or methodological acts, the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as exemplary forms of implementing the claims. 
     With that said, and as described, it should be appreciated that one or more aspects of the present disclosure transform a general-purpose computing device into a special-purpose computing device (or computer) when configured to perform the functions, methods, and/or processes described herein. In connection therewith, in various embodiments, computer-executable instructions (or code) may be stored in memory of such computing device for execution by a processor to cause the processor to perform one or more of the functions, methods, and/or processes described herein, such that the memory is a physical, tangible, and non-transitory computer readable storage media. Such instructions often improve the efficiencies and/or performance of the processor that is performing one or more of the various operations herein. It should be appreciated that the memory may include a variety of different memories, each implemented in one or more of the operations or processes described herein. What&#39;s more, a computing device as used herein may include a single computing device or multiple computing devices. 
     In addition, the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. And, again, the terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed. 
     When a feature is referred to as being “on,” “engaged to,” “connected to,” “coupled to,” “associated with,” “included with,” or “in communication with” another feature, it may be directly on, engaged, connected, coupled, associated, included, or in communication to or with the other feature, or intervening features may be present. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     Although the terms first, second, third, etc. may be used herein to describe various features, these features should not be limited by these terms. These terms may be only used to distinguish one feature from another. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first feature discussed herein could be termed a second feature without departing from the teachings of the example embodiments. 
     It is also noted that none of the elements recited in the claims herein are intended to be a means-plus-function element within the meaning of 35 U.S.C. § 112(f) unless an element is expressly recited using the phrase “means for,” or in the case of a method claim using the phrases “operation for” or “step for.” 
     Again, the foregoing description of exemplary embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.