Patent Publication Number: US-2020302447-A1

Title: Systems and methods employing searches for known identifiers of sensitive information to identify sensitive information in data

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 13/149,579, filed on May 31, 2011 and titled SYSTEMS AND METHODS EMPLOYING SEARCHES FOR KNOWN IDENTIFIES OF SENSITIVE INFORMATION TO IDENTIFY SENSITIVE INFORMATION IN DATA (“the &#39;579 Application”), now U.S. Pat. No. 10,679,218, issued Jun. 9, 2020. The &#39;579 Application included a claim for the benefit of priority to the to the May 28, 2010, filing date of U.S. Provisional Patent Application 61/349,809, titled “SYSTEMS FOR DETERMINING WHETHER BATCHES OF DATA INCLUDE STRINGS THAT CORRESPOND TO SENSITIVE INFORMATION (“the &#39;809 Provisional Application”), was made pursuant to 35 U.S.C. § 119(e). The entire disclosures of the &#39;809 Provisional Application and &#39;579 Application are hereby incorporated herein. 
    
    
     TECHNICAL FIELD 
     The present invention relates generally to methods and systems for scanning systems that collect and disseminate sensitive information (e.g., merchants&#39; systems that process transactions with payment cards, etc.) and, more specifically, to methods and systems for recognizing sensitive information (e.g., payment card account numbers, etc.) in large groups of data. 
     RELATED ART 
     Credit card and debit card, or “payment card,” processing involves a number of parties, including a card association, an issuer, a cardholder, an acquirer, and a merchant. 
     When a potential cardholder, such as an individual or an organization, wants a payment card, they approach an issuer. The issuer is a financial institution. If the potential cardholder meets certain requirements (e.g., credit rating, account balance, income, etc.), the issuer may choose to issue a payment card to the cardholder. The payment card contains sensitive information about the cardholder, including the cardholder&#39;s identity and account information, which enables the cardholder to transfer funds from an account held by the issuer or to draw against a corresponding line of credit provided by the issuer. 
     A cardholder makes a purchase, or initiates a transaction, with the payment card by presenting the same to a merchant. Information obtained from the payment card by the merchant is then processed. The information may be processed using equipment that may be provided by an acquirer, which is a financial institution with which the merchant has an established relationship. As the information is processed, it is transferred to a card association (e.g., VISA, MASTERCARD, etc.), either directly from the merchant or through the acquirer. The card association transmits the information about the transaction to the issuer. The issuer then authorizes or declines the transaction. If the transaction is authorized, the issuer funds the transaction by transferring money to the acquirer through the card association. When a debit card is used, funds are transferred from the cardholder&#39;s account with the issuer to the acquirer. When the cardholder uses a credit card, the cardholder incurs a debt with the issuer, for which the cardholder must eventually reimburse the issuer. 
     Whenever a cardholder uses a payment card to make a purchase, the merchant obtains information, including the account number, from the payment card. While that information may be obtained in a number of ways, the merchant typically uses some type of electronic processing equipment to transmit the information, by way of a communication element (e.g., an Internet connection, etc.) to its acquirer or a card association. Sometimes the information is stored in memory associated with the processing equipment. That information may be stored in groups that include long strings of data. 
     Since the processing equipment includes a communication element, any memory associated with the processing equipment may be subject to hacking. Thus, any information stored in memory associated with processing equipment may be subject to theft. When payment card information is stolen, that information may be used to make unauthorized purchases. 
     DISCLOSURE 
     In one aspect, a method of the present invention includes various embodiments of methods and systems for identifying potentially sensitive information (e.g., account numbers for payment cards, etc.). In one embodiment, strings of consecutive bytes with values that correspond to characters of interest (e.g., decimal numerals or numeric digits (i.e., a character having a value that corresponds to a base-ten, or Arabic, numeral), etc.) and with lengths that correspond to a length of sensitive information of interest (e.g., a payment card account number, etc.) are identified as including potentially sensitive information. Such a string of bytes may be referred to as a “tagged string.” 
     Once potentially sensitive information (e.g., an account number for a payment card, etc.) has been identified, the potentially sensitive information may be subjected to further evaluation to determine, with an increased likelihood, whether or not the potentially sensitive information is likely to actually comprise sensitive information. 
     In one embodiment, a tagged string that includes potentially sensitive information (e.g., an account number for a payment card, etc.) may be evaluated to determine whether or not it includes (e.g., begins with, etc.) a known identifier of sensitive information (e.g., a known bank identification number (BIN), etc). Searching may be “ordinal” (e.g., one byte searching, then two byte searching (both little endian (LE) and big endian (BE)), then four byte searching (both LE and BE), etc.) to enable the search algorithm to identify data of interest across a plurality of Unicode Transformation Formats (UTFs), or regardless of the particular type of UTF, in which the data may be encoded (e.g., UTF-8, UTF-16LE, UTF-16BE, UTF-32LE, UTF-32BE). For the sake of simplicity, the term “byte,” as used herein, includes a single byte in UTF-8 encoding, an adjacent pair of bytes in UTF-16 encoding, and an adjacent set of four bytes in UTF-32 encoding. 
     A search for a known identifier that incorporates teachings of the present invention may include an analysis of a fixed number of bytes (e.g., four, six, etc.) in (e.g., at the beginning of, etc.) a tagged string. These bytes may be evaluated in a so-called “trie” algorithm, in which a first byte is analyzed at a first node of the “trie.” If the value of the first byte does not correspond to a first value present in a known identifier (e.g., a BIN, etc.), the known identifier search may be terminated and the tagged string is no longer considered to include potentially sensitive information. If, in the alternative, the value of the first byte does match with a corresponding first value of a known identifier, the search proceeds to a second node of the trie. The value of a second byte of the tagged string is then compared with one or more second values of a known identifier that also includes the first value (i.e., a database of a group of second values that are known to follow the identified first value in a group of known identifiers). Again, if the value of the second byte does not correspond to the second value of a known identifier, the search may be terminated and the tagged string may no longer be considered to comprise potentially sensitive information. If the value of the second byte corresponds to the second value of a known identifier, the process continues to a third node of the trie, where the process is repeated. If, following conclusion of the analysis, all of the evaluated bytes match a corresponding combination of values of a known identifier, the tagged string may be subjected to further analysis. 
     In another embodiment, such further evaluation may include a delimiter search, in which the bytes adjacent to the beginning and end of the string of bytes that correspond to a tagged string of data are evaluated to determine whether a known delimiter character has been used to set a string of bytes that may corresponding to sensitive information apart from adjacent data. 
     One or more of the evaluation processes of the present invention, including, but not limited to, searching for a known identifier, may be used to provide an increased level of confidence that the bytes of a particular data string correspond to characters of potentially sensitive information of interest. Any tagged strings that are unlikely to include the potentially sensitive information of interest may be disregarded. In some embodiments, the further evaluation comprises a much less intensive process and, thus, less time to complete, than a final process for verifying whether a data string actually includes sensitive information of interest. Thus, quicker processes may be used to disregard, or weed out, the majority of data within a group, while the more intensive final process may be reserved for data strings that are likely to include the sensitive information of interest. 
     In some embodiments, known processes may be used to verify that a tagged string includes sensitive information (e.g., an account number for a payment card, etc.). In a specific embodiment, a known validation or “checksum” algorithm, such as the Luhn algorithm, may be used to determine whether or not a tagged string encodes an actual payment card account number. 
     A system of the present invention may execute one or more of the processes that have been described above. The above-described processes may be implemented in the form of a program that may be executed by processing element (e.g., computer processor, etc.) or that evaluates, or scans, stored data. The data may be stored in memory associated with the processing element, on in memory of a separate electronic device. The processing element may access the stored data by way of a suitable communication element, such as circuitry and/or wiring within the same electronic device (e.g., computer, etc.) as the processing element, a wired communication link between the electronic device of which the processing element is a part and a separate electronic device of which the memory is a part, or remotely (e.g., over an Internet connection, etc.). 
     Other aspects, as well as features and advantages of various aspects, of the present invention will become apparent to those of ordinary skill in the art through consideration of the ensuing description, the accompanying drawings, and the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a schematic representation of an embodiment of an evaluation system of the present invention, which includes a collection system and a scanning device for evaluating the collection system; 
         FIG. 2  is a diagram that illustrates an embodiment of a network in which sensitive information, such as account information corresponding to payment cards, may be collected and disseminated, and in which searches for sensitive information may be conducted; 
         FIG. 3  is a flow chart that illustrates an embodiment of a process by which data is evaluated to determine whether any sensitive information of interest has been stored therein; 
         FIG. 4  is a flow chart that depicts an embodiment in which various bytes of a tagged string of data are analyzed to determine whether their values match with corresponding values of a known identifier of sensitive data; and 
         FIGS. 4A and 4B  are schematic representations of the evaluation depicted by  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION 
     The present invention includes various embodiments of systems for evaluating data to determine whether or not the data includes potentially sensitive information.  FIG. 1  schematically depicts an embodiment of such an evaluation system  10 , in which an electronic device, referred to here is a “scanning device  20 ,” is configured to communicate with and scan data stored by a component of another electronic device that collects sensitive information, which is referred to herein as a “collection system  40 .” 
     The collection system  40  includes a memory device (e.g., a hard drive, etc.), or “memory  42 ” for the sake of simplicity, that stores data  44 , which potentially includes sensitive information. In addition to memory  42 , a collection system  40  of an evaluation system  10  of the present invention may include or be associated with a processing element  22 , such as a microprocessor, a microcontroller, or the like. 
     The scanning device  20  is programmed to determine whether the data  44  stored by the memory  42  of the collection system  40  includes any potentially sensitive information. Programming of the scanning device  20 , which may be in the form of software or firmware, controls operation of a processing element  22  of the scanning device  20 . Some embodiments of processing elements  22  that may be included in a scanning device  20  of an evaluation system  10  of the present invention include, without limitation, microprocessors, microcontrollers, and elements that may be configured to execute a particular program. In embodiments where a scanning device  20  of an evaluation system  10  of the present invention is configured for direct connection to a collection system  40 , the scanning device  20  may be portable (e.g., a laptop computer; a hand-held computer, such as a so-called “smart phone,” etc.; a dedicated scanner; etc.). In embodiments where a scanning device  20  is configured to remotely scan one or more collection systems  40 , the scanning device  20  may comprise a server, or a device (e.g., a dedicated scanning device, a smart phone, etc.) that may connect remotely to the collection system  40  (e.g., through a cellular telephone data connection, etc.). 
     Communication between the memory  42  of the collection system  40  and a processing element  22  of the scanning device  20  may be established in any suitable manner known in the art. In embodiments where both the scanning device  20  and the collection system  40  comprise electronic devices, a communication link between the scanning device  20  and the collection system  40  may be direct or indirect. A direct connection may include a physical, or “wired,” coupling between the scanning device  20  and the collection system  40 , or it may include a close proximity wireless connection (e.g., a Bluetooth connection, a wireless local area network (WLAN) (e.g., a WiFi network operating in accordance with an IEEE 802.11 standard, etc.). An indirect connection may be established more remotely (e.g., over the Internet, etc.). In some embodiments where an indirect connection is established between the scanning device  20  and the collection system  40 , the scanning device  20  of an evaluation system  10  that incorporates teachings of the present invention may be located at a central location, and may be configured to selectively communicate with a plurality of different collection systems  40  at a plurality of different locations. 
     An evaluation system  10  may be used in a variety of contexts or environments where sensitive information (e.g., account numbers, usernames and associated passwords, Social Security numbers or similar identifiers, etc.) is used. In a specific embodiment, the evaluation system  10  is configured to scan for and identify potential credit card numbers and debit card numbers, which are collectively referred to herein as “payment card numbers.” The scanning device  20  in such an embodiment may comprise a server under control of an approved scanning vendor (ASV), which is a party that has been authorized to access and evaluate the systems (i.e., the collection systems  40 , such as card readers, associated computers, etc.) employed by one or more merchants to acquire information from a consumer&#39;s payment card. 
     The relationships between the various parties that may be involved in payment card transactions are illustrated by the schematic representation of  FIG. 2 . More specifically,  FIG. 2  depicts a network  100  that includes a card association  110 ; an issuer  120 ; a cardholder, or consumer  130 ; a merchant  140 ; and an acquirer  150 . 
     The card association  110  is generally recognized as the entity whose identity appears most prominently on a payment card  132 . Examples of card associations  110  include, but are certainly not limited to, Visa, Master Card, American Express, and Discover. As depicted, the card association  110  may act as a gateway between an issuer  120  and an acquirer  150 , enabling the authorization and funding of a consumer  130 ′s transactions. In some embodiments, a card association  110  (e.g., American Express, Discover, etc.) may also serve as the issuer  120 , as depicted by box  150  in  FIG. 2 . 
     The issuer  120  may be a financial institution. As  FIG. 2  schematically represents, there is a direct relationship between the issuer  120  and each of its consumers  130 : the issuer  120  provides each of its consumers  130  with a payment card  132 . In so doing, the issuer  120  may determine whether or not each of its consumers  130  meets certain qualifications, such as credit history, income or revenue, available funds, employment status, and other indicators of the ability of a particular consumer  130  to pay for transactions that will be enabled by use of the payment card  132 . 
     The consumer  130  may be an individual, a business, or any other entity. Each consumer  130  should assume responsibility for its payment card  132 , as well as the information on or otherwise associated with the payment card  132 . 
     Each merchant  140  is a party that provides goods or services to a variety of consumers  130 . In the network  100 , a merchant  140  provides consumers  130  with the option to use payment cards  132  to complete transactions for the merchant  140 ′s goods or services. When a consumer  130  chooses to use a payment card  132  to complete a transaction, the merchant  140  uses a collection system  40  ( FIG. 1 ) to obtain account information  134  (e.g., an account number, an expiration date, information about the consumer  130 ′s identity, etc.) from the payment card  132 . That account information  134  is then transmitted, along with information about the transaction, or “transaction information  136 ,” by the collection system  40  to the card association  110 . The transaction information  136  may include data indicative of the point of sale, the date and time of the transaction, goods or services purchased as part of the transaction, the monetary amount of the transaction, and the like. 
     The account information  134  and the corresponding transaction information  136  may be transmitted to the card association  110  either directly or through the acquirer  150 , which is a financial institution (e.g., a bank, etc.) with which the merchant  140  has an established relationship. 
     The card association  110  then transmits the account information  134  and the corresponding transaction information  136  to the issuer  120 , which authorizes or declines the transaction. If the transaction is authorized, the issuer  120  funds the transaction. Where an acquirer  150  is involved, the issuer  120  transfers money  138  to the acquirer  150  through the card association  110 . When the payment card  132  is a debit card, funds are transferred from the cardholder&#39;s account with the issuer  120  to the acquirer  150 . When the consumer  130  uses a credit card, the consumer  130  incurs a debt with the issuer  120 , for which the consumer  130  must eventually reimburse the issuer  120 . 
     The Payment Card Industry (PCI), an organization that governs the network  100 , sets standards for the collection, storage, and transmission of account information  134  within the network  100 . These standards are known as PCI&#39;s Data Security Standards (DSS). In view of the ever-increasing danger that sensitive account information  134  will be stolen, the PCI often modifies, typically increasing, the DSS. 
     Each merchant  140  within the network  100  (i.e., each merchant  140  that accepts payment cards  132  from its consumers  130 ) must comply with the current version of the DSS or risk fines from PCI. In addition, a merchant  140  that does not comply with the current DSS may be liable to its consumers  130  for the misappropriation of their sensitive account information  134 . 
     In order to ensure that the merchants  140  within the network  100  comply with the current DSS, the network  100  may also include one or more approved scanning vendors  160  (ASVs). An ASV  160  is an entity that has been certified by PCI to evaluate the systems (e.g., collection systems  40 ) that are used within the network  100  to collect and transmit account information  134 , and to determine whether or not those systems are DSS compliant. Each ASV  160  may be employed by one or more merchants  140 , by one or more acquirers  150 , or by a card association  110 . 
     With returned reference to  FIG. 1 , an ASV  160  ( FIG. 2 ) may use a scanning device  20  to verify whether or not a merchant&#39;s collection systems  40  are DSS compliant. Communication may be established between the processing element  22  of the scanning device  20  and various components of a merchant  140 ′s collection system  40 , including, but not limited to, its memory  42 . Communication between the processing element  22  and the collection system  40  may be direct or remote, and may be established by any suitable technique or protocol. 
     In determining whether or not a merchant&#39;s collection system  40  is DSS compliant, the processing element  22  of the ASV  160 ′s ( FIG. 2 ) scanning device  20  operates under control of one or more programs (e.g., computer programs, etc.) to evaluate certain aspects of the collection system  40 . Various embodiments of programs that control operation of the processing element  22 , as well as the processes that are effected by such programs in accordance with teachings of the present invention, are described hereinafter. 
     In a specific embodiment, a process or program of the present invention may cause the processing element  22  of a scanning device  20  to evaluate data  44  stored by one or more components (e.g., memory  42 , etc.) of a merchant  140 ′s ( FIG. 2 ) collection system  40  to determine whether the data  44  includes account information  134  that corresponds to one or more payment cards  132  ( FIG. 2 ). More specifically, a program of the present invention may be configured to effect a process in which data  44  is evaluated to determine whether it includes any data strings that are likely to comprise payment card account numbers. Such a process  200  is illustrated by the diagram of  FIG. 3 . 
     In  FIG. 3 , at reference  210 , data  44  stored by memory  42  associated with a merchant&#39;s collection system  40  ( FIG. 1 ) is evaluated. Specifically, the data  44  is evaluated to determine whether or not it includes any strings of data that might comprise sensitive information, such as a payment card account number or the like. Without limiting the scope of the present invention, a payment card account number may be thirteen (13) to sixteen (16) digits long. In memory, or the data  44 , a payment card account number may comprise a number of consecutive bytes (e.g., thirteen (13) to sixteen (16) in UTF-8 (8-bit Unicode Transformation Format) encoding, twenty-six (26) to thirty-two (32) in UTF-16 (16-bit Unicode Transformation Format) encoding, fifty-two (52) to sixty-four (64) in UTF-32 (32-bit Unicode Transformation Format) encoding, etc.) that correspond to thirteen (13) to sixteen (16) numeric digits. 
     Any suitable technique may be used to identify each string of data within the data  44  ( FIG. 1 ) that includes the appropriate number of consecutive bytes that correspond to thirteen (13) to sixteen (16) numeric digits. One embodiment of such a method includes an “interval scanning” technique, in which a string of data is evaluated in intervals. When such a method is used, bytes of data in periodic sequence (e.g., every thirteenth byte for UTF-8 encoding, two sequential bytes of every twenty-six bytes for UTF-16 encoding, four sequential bytes of every fifty-two bytes for UTF-32 encoding, etc.) are evaluated, while the bytes in between are initially ignored. To enable the search algorithm to identify data of interest across a plurality of formats, or regardless of the particular type of format, in which the data may be encoded (e.g., ASCII/UTF-8, UTF-16LE, UTF-16BE, UTF-32LE, UTF-32BE), a so-called “ordinal” search (e.g., one byte searching for a numeric digit, then two byte searching (both little endian (LE) and big endian (BE)) for a numeric digit, then four byte searching (both LE and BE) for a numeric digit, etc.) may be conducted. 
     If the value of the byte corresponds to a decimal numeral (i.e., 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9), that byte is identified as a tagged numeric byte, from which a byte-by-byte analysis, or sequential search, may then commence. In the sequential search, bytes adjacent to both “sides” of the tagged numeric byte may be evaluated to determine whether or not they also correspond to decimal numerals. The sequential search may continue until a determination is made that the number of sequential bytes that correspond to decimal numerals is too short (e.g., &lt;13 digits, etc.) or too long (e.g., &gt;16 digits, etc.) to comprise an account number for a credit card or debit card. 
     With returned reference to  FIG. 3 , at reference  250 , an embodiment of a preliminary evaluation process that is referred to herein as a “delimiter search” may be conducted. In a delimiter search, a pair of bytes that surround a tagged string that comprises possible data of interest may be analyzed. If a delimiter search reveals that delimiters surround a tagged string, the tagged string may be identified as a “suspected sensitive data string.” Further analysis of a suspected sensitive data string may be conducted at reference  270  of  FIG. 3 . 
     At reference  270  of  FIG. 3 , a tagged string or a suspected sensitive data string may be evaluated to determine whether it includes a known identifier of sensitive data. The evaluation of a tagged string or a suspected sensitive data string to detect any known identifiers of sensitive data may be effected in any suitable manner. Such an evaluation may be conducted in an ordinal fashion (e.g., one byte searching, then two byte searching (both little endian (LE) and big endian (BE)), then four byte searching (both LE and BE), etc.). In embodiments where the data is being evaluated to identify potential account numbers for payment cards, the known identifier may comprise a bank identification number (BIN). As known in the art, BINs include four to six consecutive numeric digits, which typically comprise the first digits in an account number. 
     A BIN search that incorporates teachings of the present invention may include an analysis of a fixed number of bytes that correspond to digits (e.g., four, six, etc.) of (e.g., at the beginning of, at the end of, in the middle of, scattered throughout, etc.) a potential account number for a payment card. These bytes may be analyzed in a so-called “trie” algorithm, in which a first byte is evaluated at a first node of the “trie.” If the value of the first byte does not correspond to a first digit that is known to be present in a BIN, the BIN search may be terminated and the string of data is no longer considered to be a potential account number. If, in the alternative, the value of the first byte is equal to, or matches, a first digit of a known BIN, the search proceeds to a second node of the trie that corresponds to the identified value of the first digit (i.e., a database of a group of second digits that are known to follow the identified first digit in a group of known BINs). Again, if the second analyzed byte does not have a value equal to the second digit of any known BIN that also includes the first digit, the search may be terminated and the string of data may no longer be considered to comprise a potential account number. If the value of the second analyzed byte is equal to the second digit of a known BIN, the process continues to a third node of the trie, where the BIN search continues. If, following conclusion of the BIN search, the values of all of the analyzed bytes match the corresponding digits of a known BIN, the potential account number may be subjected to further analysis. 
       FIGS. 4, 4A, and 4B  depict a specific embodiment of a method in which a trie algorithm is used to determine whether a suspected sensitive data string includes an identifier of sensitive data. 
     At reference  272  of  FIG. 4 , the value of a selected first byte B 1  of a tagged string or a suspected sensitive data string is identified. At reference  274 , the value of the first byte B 1  is compared with a set of possible first values ID 1  of known identifiers of the type of data (e.g., BINs, etc.) being searched for. Each value is represented as a circle in  FIG. 4B . If the value of the first byte B 1  does not match a possible first value ID 1  for that particular type of data, it is apparent that the tagged string or suspected sensitive data string does not actually include the type of sensitive data for which the search is being conducted, the tagged string or suspected sensitive data string is disregarded, and the search is terminated, at reference  276 . 
     If the value of the first byte B 1  equals one of the possible first values ID 1 , process flows to reference  278 , where a group of second values ID 2  is selected that correspond to (e.g., may follow, etc.) that possible first value ID 1  in a known identifier. The value of a second byte B 2  of the tagged string or suspected sensitive data string is then identified, at reference  280 , and compared, at reference  282  with the second values ID 2 . If the value of the second byte B 2  does not match a possible second value ID 2  for that particular type of sensitive data, the tagged string or suspected sensitive data string does not include the type of sensitive data for which the search is being conducted, and the search is terminated, at reference  276 . 
     If the value of the second byte B 2  equals one of the possible second values ID 2 , process flows to reference  284 , where a group of third values ID 3  is selected that correspond to the combination of the possible first value ID 1  and second value ID 2  in a known identifier of sensitive data. The value of a third byte B 3  of the tagged string or suspected sensitive data string is then identified, at reference  286 , and compared, at reference  288 , with each of the third values ID 3 . If the value of the third byte B 3  does not match a possible third value ID 3  for a particular type of sensitive data, the tagged string or suspected sensitive data string does not include the type of sensitive data for which the search is being conducted, and the search may be terminated at reference  276 . 
     In some embodiments, if the value of the third byte B 3  matches one of the possible third values ID 3  of a known identifier of sensitive data (e.g., in embodiments where three matches to characters of the known identifier of sensitive data provides a high level of confidence (e.g., 90% or more, 95% or more, 99% or more, 100%, etc.) that the known identifier is present in the tagged string or suspected sensitive data string, etc.), the process flows to reference  290 , where the tagged string or the suspected sensitive data string may be identified as a “likely sensitive data string.” Thereafter, the process may proceed back to reference  300  of  FIG. 3 . 
     In other embodiments, further analysis may be required to provide a desired level of confidence that the known identifier of sensitive data is present in the tagged string or suspected sensitive data string. In such embodiments, the values of one or more additional bytes of the tagged string or the suspected sensitive data string (e.g., a fourth byte B 4 , a fifth byte B 5 , etc.) may be identified and compared with values of additional digits of a known identifier that includes each of the previously identified digit values (i.e., values that correspond to values of each of the first through third bytes B 1 -B 3 , values that correspond to values of each of the first through fourth bytes B 1 -B 4 , etc.). When the known identifier is a BIN, the process may continue on to a fourth byte and, in some embodiments, to a fifth byte or even a sixth byte. If the desired level of confidence (e.g., 100%, etc.) that the tagged string or suspected sensitive data string includes the known identifier of sensitive data cannot be achieved, the process flows to reference  276 , where the tagged string or suspected sensitive data string is disregarded. 
     In  FIG. 4B , the search for a known identifier of sensitive data follows the path of the solid arrows. The broken arrows identify the other groups of values that correspond to a particular value (represented as a circle) from a previous, or higher, level, or generation. 
     If, in the alternative, the analyzed bytes of the tagged string or suspected sensitive data string match with a desired level of confidence to a known identifier, process flows to reference  290 . At reference  290 , the tagged string or suspected sensitive data string is identified as a “likely sensitive data string” and the process may then flow to reference  300  of  FIG. 3 . 
     In some embodiments, the bytes B 1 , B 2 , etc., of a tagged string or a suspected sensitive data string that are analyzed in accordance with the method depicted by  FIG. 3  may comprise a series of consecutively arranged bytes that correspond to consecutively arranged digits in a known identifier. In a more specific embodiment, the analyzed bytes B 1 , B 2 , etc., may comprise the first bytes of the tagged string of the suspected sensitive data string. In other embodiments, the analyzed bytes B 1 , B 2 , etc., may be non-consecutively arranged and correspond to a parallel pattern of non-consecutively arranged digits in a known identifier. 
     In instances where the evaluation is terminated at reference  276 , process may flow to back to  FIG. 3 . The part of the process of  FIG. 3  to which the process returns may depend upon the manner in which data is being evaluated. In embodiments where the evaluation progresses completely in series; i.e., when a tagged string is subjected to further evaluation immediately after the tagged string is identified as including possible data of interest, process may flow back to reference  210  of  FIG. 3 . At reference  210 , the data  44  ( FIG. 1 ) may be searched for more possible data of interest. 
     In embodiments where further processing is not conducted until all of the data  44  has been evaluated for possible data of interest, and in which all further evaluation of a tagged string is conducted before any further processing is conducted on another tagged string, the evaluation progresses partially in series. When the evaluation progresses partially in series, the process flow may return to reference  250  of  FIG. 3 , where further evaluation of another tagged string may be initiated. 
     In embodiments where further evaluation occurs in parallel; i.e., one mode of further evaluation is conducted on all candidates (e.g., tagged strings, suspected sensitive data strings, likely sensitive data strings, etc.) before the next mode of further evaluation of conducted on remaining candidates, the process flow may return to reference  270  of  FIG. 3 . 
     Returning reference again to  FIG. 3 , at reference  300 , a likely sensitive data string that has been subjected to and has passed, or survived, at least one of the above-described evaluation processes may then be subjected to further verification. In some embodiments, known processes may be used to determine the likelihood that a string of decimal numerals is an account number for a credit card or debit card. In a specific embodiment, a known validation or “checksum” algorithm, such as the Luhn algorithm, may be used to determine whether or not a potential account number is an actual account number. 
     Once the evaluation at reference  300  is complete, the process flow may return to another location on  FIG. 3 . The location to which the process flow returns (e.g., reference  210 ,  250 ,  270 , or  300 ) depends, of course, upon whether the evaluation progresses completely in series, partially in series, or in parallel. 
     While the above-described systems and processes have been described in terms of searches for potential credit card or debit card account numbers, they are also applicable to searches for other sensitive types of information, including bank account numbers, Social Security numbers, drivers license numbers, and the like. 
     Although the foregoing description contains many specifics, these should not be construed as limiting the scope of the invention or of any of the appended claims, but merely as providing information pertinent to some specific embodiments that may fall within the scopes of the invention and the appended claims. Features from different embodiments may be employed in combination. In addition, other embodiments of the invention may also be devised which lie within the scopes of the invention and the appended claims. The scope of the invention is, therefore, indicated and limited only by the appended claims and their legal equivalents. All additions, deletions, and modifications to the invention, as disclosed herein, that fall within the meaning and scopes of the claims are to be embraced by the claims.