Abstract:
A magnetic interface card appears to be a payment card conventionally provided with an electromagnetic stripe and magnetic data tracks. A magnetic emissive element is disposed in the magnetic interface card body under the magnetic data tracks that can emit a variety of ISO-7813 track- 2  data strings. A photo-sensor is included to receive a series of optically encoded flashes from a personal trusted device (PTD) smartphone screen that securely communicate one-time-use account information and operational parameters from a financial transaction server. The large installed base of legacy point-of-sale magnetic card readers can continue to be used without any hardware or software modifications, and card security is improved by the change to one-time-use access numbers.

Description:
COPENDING APPLICATION 
       [0001]    This application is a Continuation-in-Part of U.S. patent application Ser. No. 12/752,390, filed Apr. 1, 2010, and titled MAGNETIC EMISSIVE USE OF PRELOADED SECRET-KEY ENCRYPTED USE-ONCE PAYMENT CARD ACCOUNT NUMBERS, by the present inventor, Kerry D. Brown. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to magnetic track payment cards compatible with existing point-of-sale card readers, and more particularly to payment cards that can receive account security data optically from user smartphones and laptops and use it to magnetically output ISO-7813 track data. 
         [0004]    2. Description of Related Art 
         [0005]    Conventional credit cards, debit cards, and other payment cards use a single account number that is open for all to see (and duplicate). Any fraudster that has been handed the magnetic interface card, read it, or otherwise managed to record the account number had little trouble in running charges up against the account. So merchants and banks started requiring identification, billing addresses, expiration dates, holograms, signature panels, and now security codes before completing a transaction. But loose enforcement of these measures has not really put much of an obstacle in the fraudsters&#39; paths. 
         [0006]    Use-once account numbers are an excellent way to control these types of fraud, but the use-once number needs to be magnetically readable by a legacy card reader or presented on a user display. These both require the inclusion of active electronics in the magnetic interface cards that raises the unit costs of the magnetic interface cards themselves and that often depend on batteries for their continued operation. 
         [0007]    The technology required to put dynamic electromagnetic stripes on payment cards is very challenging. It would be desirable to have all the bits in every magnetic data track be programmable by the magnetic interface card itself so the use-once account numbers could be freely updated. Current magnetic device technology is further not up to the challenge of the high bit recording densities needed on track-1 of the typical payment card at a cost acceptable to the card issuers and payment associations. 
         [0008]    User account data is recorded on the electromagnetic stripes of conventional payment cards using industry-standard formats and encoding like ISO-7810, ISO-7811(−1:6), and ISO-7813, available from American National Standards Institute (NYC, NY). Such standards specify the physical characteristics of the magnetic interface cards, how to do the embossing, the electromagnetic stripe media characteristics for low-coercivity, the permissible locations for any embossed characters, the location of data tracks 1-3, any high-coercivity electromagnetic stripe media characteristics, etc. 
         [0009]    A typical Track-1, as defined by the International Air Transport Association (IATA), as being seventy-nine alphanumeric 7-bit characters recorded at 210-bits-per-inch (bpi) with 7-bit encoding, Track-2, as defined by the American Bankers Association (ABA), is forty numeric characters at 75-bpi with 5-bit encoding, and Track- 3  (ISO-4909) is typically one hundred and seven numeric characters at 210-bpi with 5-bit encoding. Each track includes starting and ending sentinels, and a longitudinal redundancy check character (LRC). The Track-1 format can include user primary account information, user name, expiration date, service code, and discretionary data. Conventional payment card magnetic tracks conform to the ISO/IEC Standards 7810, 7811-1-6, and 7813, and other formats. 
         [0010]    The ISO 7810/7816 specifications and ABA/IATA stripe data fields describe a “discretionary field”, and “other data field” that can be used exclusively for the issuing bank. The discretionary fields can be used for status bits and other operators. 
         [0011]    Authentication factors are pieces of information that can be used to authenticate or verify the identity of a cardholder. Two-factor authentication employs two different authentication factors to increase the level of security beyond what is possible with only one of the constituents. For example, one kind of authentication factor can be what-you-have, such as electromagnetic stripe credit card or the SIM card typical to many mobile devices and personal trusted device (PTD). The second authentication factor can be what-you-know, such as the PIN code that you enter at an ATM machine. Using more than one authentication factor is sometimes called “strong authentication” or “multi-factor authentication,” and generally requires the inclusion of at least one of a who-you-are or what-you-have authentication factor. 
         [0012]    What is needed is a payment card that can magnetically provide use-once account numbers to legacy card readers. Especially payment cards that can receive card data updates from a PTD, in effect allowing the PTD to access ubiquitous magnetic-swipe point-of-sale (POS) terminals without actually having to modify the terminals themselves. 
       SUMMARY OF THE INVENTION 
       [0013]    Briefly, a payment card embodiment of the present invention appears to be conventionally provided with an electromagnetic stripe and magnetic data tracks. A magnetic emissive element is disposed in the magnetic interface card body under the magnetic data tracks that can emit a variety of track data strings. A photo-sensor is included to receive a series of optically encoded flashes from a personal trusted device, such as smartphone screen, that securely communicate one-time-use account information and operational parameters from a financial transaction server. The large installed base of legacy point-of-sale magnetic card readers can continue to be used without any hardware or software modifications, and card security is improved by the change to one-time-use access numbers. 
         [0014]    The above and still further objects, features, and advantages of the present invention will become apparent upon consideration of the following detailed description of specific embodiments thereof, especially when taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIGS. 1A and 1B  are functional block diagrams of payment system embodiments of the present invention in which account and control data downloaded by a personal trusted device by optical, audio, or near field communication (NFC) wireless links; 
           [0016]      FIGS. 2A-2C  are a schematic diagram of a financial payment system embodiment of the present invention, and back and front views of a payment card that divides the magnetic data tracks into a first half and a second half to control inter-channel crosstalk.  FIG. 2B  illustrates the back of the payment card and shows how two magnetic data tracks can be divided into partial data tracks to control crosstalk.  FIG. 2C  illustrates the magnetic interface card front and shows a way to place two swipe sensors and a photosensor; 
           [0017]      FIG. 3  is a flowchart diagram of financial payment system embodiment of the present invention that uses symmetric key encryption of account numbers, expiry numbers, and sequence numbers for use once cryptograms in payment cards; 
           [0018]      FIG. 4  is a perspective diagram showing how an inductive coil can be placed under the track-2 area of a electromagnetic stripe and read by a legacy card reader; 
           [0019]      FIG. 5A  is a schematic diagram of a two track implementation of inductive coils placed under the track-1 and track-2 areas of a electromagnetic stripe and read by a legacy card reader; 
           [0020]      FIG. 5B  is a schematic diagram of a two track implementation of a conventional magnetic data track and an inductive coil placed under the track-1 and track-2 areas of a electromagnetic stripe and read by a legacy card reader; 
           [0021]      FIG. 5C  is a schematic diagram of a two track implementation of a conventional magnetic data track and an inductive coil placed under partial track track-1 and track-2 areas of a electromagnetic stripe and read by a legacy card reader; 
           [0022]      FIG. 6  is a functional block diagram of an access card embodiment of the present invention with an emissive coil element; 
           [0023]      FIG. 7  is a functional block diagram of a thin-client access card embodiment of the present invention with an emissive coil element with an acoustic modem and piezoelectric device; and 
           [0024]      FIG. 8  is a functional block diagram of autonomous access card embodiment of the present invention with an emissive coil element and a display. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0025]    Embodiments of the present invention provide an interface card that is used like a conventional credit or debit card in any magnetic card reader used by point-of-sale (POS) merchants throughout the world. These magnetic interface cards are trademarked by Cryptite, Inc. as INTERPOSER™ CARDS and give the appearance of being an ordinary payment card. They are periodically charged up with use-once account numbers by a smartphone or other personal trusted device (PTD) and fully autonomous thereafter. 
         [0026]    In effect, such INTERPOSER cards extend the computing reach of a PTD to magnetic-swipe POS terminals and overcome the severe limitations of conventional magnetic cards caused by their fixed and unchangeable magnetic data payloads. The fixed nature of these conventional cards has been a serious security flaw. A complete system therefore comprises both the PTD and the INTERPOSER card. 
         [0027]      FIG. 1A  represents an improved payment system embodiment of the present invention, and is referred to herein by general reference numeral  100 . System  100  uses a bank  102 , trusted service manager (TSM), or other payment card issuer, to pre-compute user account numbers and corresponding cryptograms  104 . These are encrypted, e.g., with a secret key using a symmetric-key algorithm. The secret keys are used by the bank&#39;s symmetric-key algorithms for both encrypting and decrypting partial or complete account numbers into corresponding cryptograms  104  that represent control and account data. The account data in corresponding cryptograms  104  are each typically used only once. 
         [0028]    The Internet and a wireless connection  106 , such as Wi-Fi/3G/4G, etc., are used to communicate control and account data  108  after being authenticated with a smartphone or other personal trusted device (PTD)  110 . More than a user&#39;s ID and password can be used to authenticate PTD  110  to bank  102 , the “IEM” or “UDID” serial number of a smartphone and the “SIM” card data can be included as well to strengthen security. The iPhone Unique Device Identifier (UDID) is a hash of several different hardware identifiers pulled from the chips on the phone. It&#39;s not a software-generated identifier for a software object. Colorgrams and other external tokens can also be effectively included. 
         [0029]    Typical PTD&#39;s have enough processing power available to engage in strong authentication sessions. It&#39;s not practical to put such computing capabilities in a smartcard with today&#39;s technology, and the costs to do it are prohibitive. The control and account data  108  is translated by a magnetic interface application (app) program  111  into a series of encoded flashes  112  that are presented on a display screen  114 . Account and operational data  115  are communicated by the series of encoded flashes  112  and includes some or all of the information in the control and account data  108 , as well as other information that may need to be inserted by PTD  110 . 
         [0030]    The Apple iPhone may not presently be able to accurately and precisely sequence encoded flash data to its screen. But this may not be true with Android, and other types of smartphones. The asynchronous communication methods mentioned herein may not be necessary in future. Synchronous communications may be simple to do in other devices, or in the iPhone itself in the near future. As more devices use screen communications, their operating systems will no doubt be improved to accommodate good synchronous communications. 
         [0031]    A magnetic interface card  116  is typically laid down by the user right over the display screen  114  to receive the series of encoded flashes  112  with an embedded one-bit photosensor. The flashes presented can be white light. Colors may be used in special applications and color filters can be used in front of the embedded one-bit photosensors to discriminate between applications. Spectral emission amplitude and frequency/color may also be included to assist in a mutual authentication of the PTD-magnetic interface system. 
         [0032]    The typical user would not ordinarily see the screen flashes when the magnetic interface card is laid flat on the display screen. A button or some other mechanism can be used to signal the magnetic interface card  116  when it should wake up to accept the optical download. Once a download is completed, magnetic interface card  116  may audibly signal the user and/or the PTD through its microphone that the download succeeded. An encoded audio signal can also be sent to the PTD related to health issues, battery life, etc. 
         [0033]    Once loaded, the magnetic interface card  116  becomes completely autonomous and can be used, at least a few times, as an ordinary payment card in a standard merchant magnetic card reader. The security advantage is a stolen magnetic interface card  116  would quickly run out of valid charge numbers and if it were reported stolen quickly those charge numbers that were still unused could be instantly invalidated. 
         [0034]    There are at least three operational advantages in having the magnetic interface card  116  laid down flat on the display screen  114  to receive the series of encoded flashes  112  with an embedded one-bit photosensor. The first is that ambient light can be blocked and not allowed to interfere with the embedded one-bit photosensor. The second is only a small spot on the display screen  114  corresponding in position to the embedded one-bit photosensor need be dedicated for use by the series of encoded flashes  112 . For example, the emissive area on the display screen  114  can be less than 0.25″ square. The third advantage is the series of encoded flashes  112  are not visible to others and cannot be intercepted and misused. 
         [0035]    The account and operational data  115  accepted by magnetic interface card  116  is used to build “softcards” that are stored in a non-volatile cache memory. Softcards are virtual credit and payment cards stored in electronic form. Each softcard can represent a particular payment account from VISA, MASTERCARD, AMEX, DISCOVER, etc. Here, each softcard is a one-time-use account, and each can be accompanied by more than enough to last a typical user a few days of shopping. The remaining data is used for various housekeeping chores. 
         [0036]    PTD  110  is configured by its magnetic interface application program  111  to translate “softcard” digital data received from an issuer  102  or other source to video that can be presented on display screen  114 . For example, live motion can be represented at a conventional thirty frames-per-second (FPS). But the control and account data  108  being translated into account and operational data  115  may require work to synchronize the data with the frame rate by the PTD&#39;s operating system (OS). However, overhead processes, multi-tasking, screen graphic drivers limitations, screen “persistence” and capacitive affects can all interfere with efforts to synchronize the display for optical bit-at-a-time reading by magnetic interface card  116 . 
         [0037]    One solution to such a synchronization work overload problem would be to package data  108  into a MPEG-4 movie file for presentation on display screen  114 . Conventional movie files often have their own sync coding sync methods to produce smooth data frame sequences. Another solution is to configure magnetic interface card  116  to be capable of asynchronous serial data reception from display screen  114 . The data rate may vary considerably, 10-60 FPS, but the data bit rate within a data frame sequence should be accurately clocked, e.g., within 10-20%. Prototypes that were built transmitted at 30-FPS, and included about twenty-five bits for each frame. These bits had to be accurate within the frame in order to distinguish a digital “1” from a “0”. 
         [0038]    PTD  110  can add data to the discretionary fields in the magnetic payment card track data to communicate cryptogram version levels, origination of cryptograms, location of download system for cryptograms, MAC address or UUID/UDID address of device used to download cryptograms, etc. 
         [0039]    Account and operational data  115  typically includes at least some of the track-1 or track-2 data, and variable data sets or cryptograms that enable use-once card functions. The data transmission from the PTD may also include softcard identifiers in the event the magnetic interface card includes more than a single instance of a payment card type, issuer, card association, or similar. Card types include debit, credit, rewards, loyalty, etc. The card can also assemble data transmitted to the PTD for multiple card types, associations, issuers, debit/credit, etc. 
         [0040]    A battery  118  inside magnetic interface card  116  allows preloaded account and operational data  115  to be retained for a reasonable time, and to operate autonomously in several financial transactions with a conventional magnetic-stripe merchant card reader  120 . The number of autonomous transactions allowed can be software defined to suit the users or issuers. 
         [0041]    An electromagnetic stripe  122  generates a magnetic data readout  124  whenever magnetic interface card  116  is swiped in the merchant card reader  120 . Such magnetic data readout  124  will include some data that was originally transmitted in the control and account data  108 . Bank  102  can thereafter be queried by the merchant card reader  120  to authenticate the magnetic interface card  116  using the magnetic readout  124  it received. 
         [0042]      FIG. 1B  represents an alternative payment system embodiment of the present invention that uses near field communications (NFC), and is referred to herein by general reference numeral  130 . Here, a PTD  130  includes an NFC transceiver  132  that is used to communicate the account and operational data  115  to the magnetic interface card  116  over an NFC wireless link  134 . The advantage of NFC wireless link  134  is it is two-way and the PTD  130  and magnetic interface card  116  can use it to mutually authenticate one another. The operation and use of magnetic interface card  116  is otherwise the same as in  FIG. 1A . At present, only a small minority of mobile devices can support NFC, while the vast majority of them have display screens that can be used to support the series of encoded flashes described in  FIG. 1A . 
         [0043]      FIGS. 2A-2C  represent an improved payment system embodiment of the present invention, and is referred to herein by the general reference numeral  200 . A bank  202  or other payment card issuer sends precomputed cryptogram tables  204  to a personalization bureau  206 . A blank magnetic interface card  208  is loaded with the precomputed cryptogram tables  204  and personalized for specific users before being issued and distributed. 
         [0044]    Magnetic interface card  208  includes a electromagnetic stripe  210  with four partial tracks  211 - 214  divided longitudinally by a gap  216 . Partial tracks  211 - 212  lie in a Track-1 recognized by magnetic card reader  120 , for example, and partial tracks  213 - 213  lie in a Track-2. Any of partial tracks  211 - 214  can be implemented as conventional magnetic recordings, or implemented with an inductor that emits serially time encoded electro-magnetic fields to mimic those of a conventional magnetic recording being swiped past a read head, e.g., in legacy card reader  120 . A pair of swipe detectors  218  and  219  are provided, and can be implemented with piezo-electric sensors. A photosensor  220  is embedded to support the optical communication functions described in  FIG. 1A . 
         [0045]    Piezo-electric devices when used as sensors can also be used as beepers, giving the card the ability to provide users with audio feedback in the form of beeps. The beeps can be a simple user notification of successful programming, or they can be encoded so a PTD microphone can receive interactive acknowledgements. 
         [0046]    An issued magnetic interface card  222  can therefore provide magnetic data  224  that simulates all the static data normally provided in Track-1 and Track-2 of conventional payment cards and is compatible with a legacy magnetic card reader  226 . The difference is the inductors can dynamically change the data they transmit to accommodate use-once cryptograms and account numbers that must be changed for every transaction. 
         [0047]    In conventional payment cards, magnetic bit data is laid out on a standard electromagnetic stripe in three tracks. A electromagnetic stripe card may have any of these tracks, or a combination of the three tracks. Magnetic interface cards  208  and  222  use only track-1 and track-2. 
         [0048]    Track-1 was standardized by the International Air Transportation Association (IATA) and is still reserved for their use. It is 210-bpi with room for seventy-nine 7-bit characters, six data bits plus one parity bit in ASCII. Track- 3  may be used for purposes defined by the card associations, the issuers, etc. 
         [0000]                              TABLE I               Track 1 Fields                                Start sentinel   1 byte (the % character)       Format code   1 byte alpha (The standard for financial           institutions specifies format code is “B”)       Primary Account   Up to nineteen characters. American Express       number   inserts space characters in here in the same           places the digits are broken up on the face of           the magnetic interface card.       Separator   1 byte (the {circumflex over ( )} character)       Country code   3 bytes, if used. (The United States is 840)           This is only used if the account number begins           with “59.”       Surname       Surname   (the / character)       separator       First name or       initial       Space   (when followed by more data)       Middle name or       initial       Period   (when followed by a title)       Title   (when used)       Separator   1 byte ({circumflex over ( )})       Expiration date   4 bytes (YYMM) or the one byte separator if a -       or separator   non-expiring card.       Discretionary   Optional data can be encoded here by the       data   issuer.       End Sentinel   1 byte (the ? character)       Longitudinal   1 byte. The LRC is made up of parity bits for       Redundancy Check   each “row” of bytes, making the total even.       (LRC)   That means that the total of all the bit ones           of each byte has to come out to an even number.           Same for bit 2, etc. The LRC&#39;s parity bit is           not the sum of the parity bits of the message,           but only the parity bit for the LRC character           itself. (It&#39;s odd, just like any other single           byte&#39;s parity bit.)                    
Track 2 was developed by the American Bankers Association (ABA) for on-line financial transactions. It is 75-bpi with room for forty 5-bit numeric characters, four data bits plus one parity bit.
 
         [0000]    
       
         
               
             
               
               
               
             
           
               
                 TABLE II 
               
               
                   
               
               
                 Track-2 Fields 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Start sentinel 
                 1 byte (0x0B, or a; in ASCII) 
               
               
                   
                 Primary Account 
                 Up to 19 bytes 
               
               
                   
                 Number 
               
               
                   
                 Separator 
                 1 byte (0x0D, or an = in ASCII) 
               
               
                   
                 Country code 
                 3 bytes, if used. (The United States is 
               
               
                   
                   
                 840) This is only used if the account 
               
               
                   
                   
                 number begins with “59.” 
               
               
                   
                 Expiration date or 
                 4 bytes (YYMM) or the one byte separator 
               
               
                   
                 separator 
                 if a non-expiring card 
               
               
                   
                 Discretionary data 
                 Optional data can be encoded here by the 
               
               
                   
                   
                 issuer. 
               
               
                   
                 End Sentinel 
                 1 byte (0x0F, or a ? in ASCII) 
               
               
                   
                 Longitudinal 
                 1 byte. 
               
               
                   
                 Redundancy Check 
               
               
                   
                 (LRC) 
               
               
                   
                   
               
             
          
         
       
     
         [0049]    Track- 3  is also occasionally used for financial transactions. The difference is in its ability to read/write. It also is 210-bpi, but with room for one hundred and seven numeric digits. Track 3 is used to store the enciphered PIN, country code, currency units, amount authorized, subsidiary account information, and other account restrictions. Track- 3  has the same properties as track-1, e.g., start and end sentinels and an LRC byte. But there is no standard for the data content or format. Track- 3  is not currently used by any national bank card issuer, but could be used in any of the embodiments of the present invention described here. 
         [0050]    Electromagnetic stripe  122  can be employed in credit cards, time and attendance, personnel identification, ATM cards, bank cards (credit and debit cards including VISA and MasterCard), gift cards, loyalty cards, driver&#39;s licenses, telephone calling cards, membership cards, electronic benefit transfer cards, and other applications. Examples of cards which intentionally ignore ISO standards include hotel key cards, most subway and bus cards, and some national prepaid calling cards in which the balance is stored and maintained directly on the stripe and not retrieved from a remote database. 
         [0051]    There are two types of static magnetic encoding materials standards, high-coercivity (HiCo) at 4000 Oe, and low-coercivity (LoCo) at 300 Oe but it is not unusual to have intermediate values at 2750 Oe. Coercivity is the measure of magnetic intensity that must be applied to a material to remove the residual magnetism when it has been magnetized to saturation. A magnetic interface card encoded with high-coercivity is less at risk of being accidentally erased than a low-coercivity encoded card. Most card systems support both types of media, but high-coercivity is generally recommended, especially for ID badges. 
         [0052]    In practical terms, low coercivity electromagnetic stripes are usually a light brown color, and high coercivity stripes are nearly black. Exceptions include a proprietary silver-colored formulation on transparent American Express cards. High coercivity stripes are resistant to damage from most magnets likely to be owned by consumers. Low coercivity stripes are easily damaged by even a brief contact, e.g., with a magnetic purse strap or fastener. Virtually all bank cards are therefore encoded with high coercivity stripes despite the slightly higher cost per unit. 
         [0053]      FIG. 3  represents a financial payment system  300 , in an embodiment of the present invention. It provides strong authentication of a user and their payment during a financial transaction. At a card issuing bank, association, or trusted service manager, an account number from a generator  302 , an expiry date  304 , and a sequence number from a generator  306  are grouped into tables. Symmetric encryption  308  and a secret key  310  are used to build cryptogram tables  311 - 315  for corresponding individual user magnetic interface cards  321 - 325 . These can include full or partial data, and are communicated with NFC, optically, by audio tones, or a feature connector cable. 
         [0054]    For example, when a particular individual user magnetic interface card  325  is used in successive financial transactions with a merchant, a card swipe  326  by a legacy card reader  328  will sequentially collect use-once, non-predictable table values  331 - 334 . A particular use-once, non-predictable table value  331 , for example, will be forwarded to a merchant point-of-sale (POS) terminal  340 . A second authentication factor  342  may be collected, such as a personal identification number (PIN) or card verification value (CVV 2 ) that would only be known to the user or someone actually in possession of magnetic interface card  325 . An electronic request  344  is forwarded to a payment processor  346  for transaction authorization. The particular use-once, non-predictable table value  331  is forwarded in a message  348  for symmetric decryption  350  using what should be secret key  310 . The decryption will reconstruction the user account number, the expiry, and the sequence number. Tests  352 ,  354 , and  356  check that these are correct, or within expected bounds. A transaction approval decision  358  is formulated. An approval depends on a check  360  of the second authentication factor  342 . A signal  362  is returned as a reply  364  to the POS terminal  340 . 
         [0055]      FIG. 4  represents a magnetic data reading system  400 , in an embodiment of the present invention. A electromagnetic stripe  402  is similar to electromagnetic stripes  122  ( FIGS. 1A-1B ),  210  ( FIG. 2B ), and on magnetic interface cards  321 - 325  ( FIG. 3 ). There are three magnetic data tracks, track-1  404 , track-2  405 , and track- 3   406 , similar to tracks  211 - 214  in  FIG. 2B . Tracks  404  and  406  are conventional, track-2  405  is one embodiment of the present invention. A read head  410  is conventional and is a usual part of a legacy card reader, such as  120  in  FIGS. 1A-1B ,  2 A, and  3 . 
         [0056]    Static magnetic bits are defined with two sub-intervals, the clock and the data sub-interval. The static magnetic stripe data is oriented in North-South sub-intervals to signify transitions from one sub-interval to another. It is these transitions that are decoded by the POS read head. The embodiments herein rely on the ability of the POS read head to distinguish sub-interval transitions. Either by the changing flux fields via North-South magnetic pole switching, or by an emissive coil producing a square wave that emulates these transitions. The transitions are not required to be zero-crossing. They only need to be inductively coupled to the head for a period of time, followed by a reduction of the head flux to nearly zero. 
         [0057]    A deposited-film inductive coil  420  is shown highly simplified in  FIG. 4 , and is driven by a logic device  422  used as a driver. When a swipe of read head  410  on electromagnetic stripe  402  is detected, a swipe data signal  424  and a bit rate clock  426  will commence. The result will be to spoof read head  410  into accepting track-2  405  data that appears to be conventional. Of course, inductive coils could also be used under either or both of track-1  404  and track- 3   406 . 
         [0058]      FIG. 5A  represents a fully dynamic two track configuration  500 , in an embodiment of the present invention that places two fully emissive inductive loops  502  and  504  side-by-side in tracks- 1  and track-2 in a electromagnetic stripe mounted on a magnetic interface card. A two-track read transducer  506  in a conventional legacy card reader has a first gap  508  that reads track-1  502 , and a second gap  510  that reads track-2  504 . A track-1 encoder  512  formats a serial digital stream for loop driver  514  that conforms to IATA, 210-bpi, 79 seven-bit character standards. A track-2 encoder  516  formats a serial digital stream for loop driver  518  that conforms to ABA, 75-bpi, 40 five-bit character standards. 
         [0059]      FIG. 5B  represents a mixed conventional track-1 and a fully dynamic track-2 configuration  520 , in an embodiment of the present invention that places fully emissive inductive loop  504  alongside a conventional track-1 in a electromagnetic stripe mounted on a magnetic interface card. A conventional two-track read transducer  506  in a legacy card reader has a first gap  508  that reads track-1  522 , and a second gap  510  that reads track-2  504 . As in  FIG. 5A , track-2 encoder  516  formats a serial digital stream for loop driver  518  that conforms to ABA, 75-bpi, 40 five-bit character standards. 
         [0060]      FIG. 5C  represents a reduced channel cross talk configuration  540 , in an embodiment of the present invention that staggers a fully emissive track-1 inductive loop  542  with respect to a foreshortened, but otherwise conventional track-2 in a magnetic stripe mounted on a magnetic interface card. In the context of  FIG. 2B , these would be partial tracks  214  and  211 , respectively. As before, conventional two-track read transducer  506  in a legacy card reader has a first gap  508  that reads track-1  544 , and a second gap  510  that reads track-2  546 . A track-2 encoder  546  formats a serial digital stream for loop driver  548  that conforms to ABA, 40 five-bit character standards, but at a square wave frequency of up to 15 kbps. Inductively coupled emissive data does not have to conform to a standard BPI level, since most POS readers accept data rates up, and even beyond, 7-kps. For this reason, the emissive element active area can remain short. When an emissive element is placed under a permanently recorded magnetic stripe, its length must be as long as the data recording length or have means to interface static magnetic data with the dynamic emissive data start and end points. 
         [0061]    Industry standard card body sizes are 3.375″ long by 2.125″ wide by about 0.031″ thick. ISO Standard 7810 relates to the Physical characteristics of credit card size document; 7811-1 Embossing; 7811-2 Electromagnetic stripe-low coercivity; 7811-3 Location of embossed characters; 7811-4 Location of tracks 1 &amp; 2; 7811-5 Location of track 3; 7811-6 Electromagnetic stripe-high coercivity; and, 7813 Financial transaction cards. 
         [0062]      FIG. 6  represents an access card  600  that includes a card body  602  with an emissive element  604 , electronic signal conditioners  606 , a swipe sensor  608 , and audio output device  609  for user or PTD communications, and a cable  610  that is attached as a peripheral to a mobile device  612 . 
         [0063]    Audio output device  609  is used in many embodiments of the present invention for sounding out feedback data in tones and/or indicating a process within the magnetic interface card has concluded. For example, it may be included in the access cards described in  FIGS. 7-8  as well. 
         [0064]    No battery or PIC is ordinarily needed in peripheral access card  600  since it relies on the mobile device  612  to do decryption and security management and to output an audio signal with coded pulses that can be signal conditioned and directly introduced for reading through the emissive element  604  by a legacy card reader. The access card  600  is a thin-client, and simply an interface device to a legacy card reader in a compatible card format. The emissive element  604  can be a deposited-film inductive coil with predefined intra-track and inter-track spacings that correspond to particular data recording tracks, and that have zero persistence after a transfer of data. 
         [0065]      FIG. 7  represents an access card  700  that includes a card body  702  with an emissive element  704 , electronic signal conditioners  706 , a swipe sensor  708 , and an acoustic modem  710  that couples to an earphone or speaker of a mobile device  712 . A battery wouldn&#39;t be needed if a piezo-electric battery-generator  714  were included in peripheral access card  700 . Mobile device  712  could also be relied on to do decryption and security management. 
         [0066]      FIG. 8  represents a magnetic interface card  800  with a card body  802 , a battery  804 , a microcontroller or peripheral interface controller (PIC)  806  with a cryptogram storage, a photosensor  808 , a pair of swipe sensors  810 , and an inductive element  812 . PIC  806  can be a PIC1650 by Microchip Technology (Chandler, Ariz.). Inductive element  812  magnetically couples to a merchant POS card reader, via one, two, or all three magnetic tracks  814 - 816 . The three tracks  814 - 816  are formatted as ABA, IATA, and a proprietary track. The IATA track can be an ISO or ANSI track, according to bank association and issuer requirements. 
         [0067]    Magnetic interface card  800  implements all the magnetic bit elements as programmable and dynamic on either or both of track-1 and track-2. A one-way optical link  820  uses light flashes to download encoded credit and payment “softcards” from a mobile personal trusted device  822 . Such light flashes can be monochromatic, visible, or infrared (IR) type light, but will usually consist of the ordinary light produced by a color cellphone display screen. Magnetic interface card  800  can further include a digital display  824  to show coupons, personal information, authentication tokens for online usage, etc. 
         [0068]    Access card  800  is an independent autonomous card that can be used for up to three years in the field, and has dynamic data elements, similar to those previously described by the present inventor, Kerry D. Brown in various issued United States Patents and published Patent Applications. 
         [0069]    When a softcard in a cache within a magnetic interface card is used, the issuer is notified of its use through the transaction processing network. An alert may be returned to the PTD to the user if their cache of softcards is running low. The user or issuer/association may decide, e.g., in a softcard application settings menu, to maintain the cache of softcards either in the PTD and/or the magnetic interface card. Alternatively, the user can be required to request of a new softcard number for each transaction. 
         [0070]    Having fewer softcard numbers stored in the magnetic interface card improves security because fewer unauthorized transactions of a misused or stolen card would be possible. Fewer softcard numbers stored means more frequent PTD authentications and log-ins would occur, increasing security. Card usage notifications may be returned just prior to battery expiration, along with other card maintenance and monitoring data. 
         [0071]    Store loyalty cards, such as Macy&#39;s, Bloomingdales, etc., that are promoted by merchants to buyers of merchandise can be maintained for the magnetic interface card. A merchant/clerk will ask if the buyer would like to apply to a loyalty card with some percentage discount on their present purchase. They will be advised they can log on to a certain site, perhaps transmitted to their phone by SMS from the clerk/merchant, and a loyalty app (Bloomingdale&#39;s, Macy&#39;s, etc.) will be loaded onto their PTD. The softcard data will be sent when their application is approved, and loyalty coupons will be managed by the app. The user/owner/buyer will also be advised of loyalty partner programs, and may be given a magnetic interface card when their application is approved. The magnetic interface card may be cobranded (Sears and Visa), or loyalty partner branded (Macy&#39;s and their partner group), or just be a PayPal account with multiple links to cards registered with PayPal (e.g. Visa debit, MC credit, AMEX credit, etc.). The novelty is that you can now register multiple cards with PayPal for use on the magnetic interface card, which in and of itself is agnostic. Each magnetic interface card assembles the PTD data with the corresponding card types registered in the within. 
         [0072]    The piezo-electric swipe sensors  218  and  219  ( FIG. 2C ) can be configured to do double duty as miniature speakers so the magnetic interface card can be made to “beep”, e.g., when it has completed being programmed by the PTD  110 . PTD  110  can be configured to beep/vibrate when a programming cycle is complete. For example, to provide the user and/or the PTD microphone with an audio indication an operation has completed or was successful. 
         [0073]    A magnetic interface card is “programmed” using various pieces of softcard data that must be forwarded by the PTD. The PTD receives important parts of account data from the issuer/card association/cloud/TSM/etc. The data is assembled and check-summed. Each card must be matched to its user, and the corresponding PTD. Someone else&#39;s PTD and its softcard data cannot be high-jacked on the magnetic interface card, thus providing a low-level form of mutual authentication. 
         [0074]    An alternative version of the magnetic interface card configured for merchants stores no data at all. If a user with the right application on their own PTD needs to, they can use the merchants card for temporary transactions on the magnetic swipe POS. The advantage is similar to signing up people for credit cards at Sears, or other stores, at the time of purchase. The merchant may offer 5% discount if they sign up for the Sears PTD card application. They could then receive authorization to download the app, the newly issued Sears softcard, and make a purchase at the terminal. 
         [0075]    The potential marketing opportunities for the PTD application and this novel card are along the same lines as present marketing operations for promoting branded credit cards. The magnetic interface card can automatically clear itself of any stored partial softcard data when an attempt to program it by another PTD is made. 
         [0076]    magnetic interface cards are extensions of mobile PTD eWallet applications. The PTD offers receipts for purchases, purchase notifications, coupon/groupon storage, web-based purchase capability (Amazon, etc.), OTP number generation, a screen for display (hence no need for a display on the magnetic interface card, at least in the primary embodiment), and a host of features that an interface card, or normal payment card, can&#39;t offer. 
         [0077]    A PTD in combination with a magnetic interface card can be used at any magnetic-swipe POS. Embodiments with the optical interfaces to the magnetic interface card, and that use partial softcard data, provide better security than an NFC type. The data sent by PTD&#39;s to their respective magnetic interface cards is only partial data to a parsed dynamic/cryptogram. 
         [0078]    A fraudster can press an NFC terminal up against a wallet to surreptitiously acquire transaction data. NFC uses radio frequency (RF) signals that are suspected to be harmful. Optical programming interfaces use no RF. 
         [0079]    Piezo-crystal elements can be used for the swipe detectors, but other devices and methods can be used as well. One novel method discriminates a real card swipe from other kinds of vibrations, card flexing, and other “noise”. Two swipe sensor crystal elements are connected to a basic full-wave diode bridge to rectify their outputs. The output signals from the bridge are input into a microcontroller to sense physical activity. Common mode vibrations like hitting, dropping, sitting on the magnetic interface card, etc., would result in both piezo crystals generating similar voltages, resulting in a nulling out of their common-mode vibrations. A strong signal from one piezo crystal, and a weak/no voltage from the other crystal would produce a high differential voltage. When the amplitude exceeds a threshold, a trigger to a state-machine causes softcard data, for example, to be transmitted to the magnetic emissive element. 
         [0080]    Piezo-electric crystals may be used as swipe detectors and also as an audible communication device for the user and the PTD. It, or another audible device, can be used to provide the closed loop system feedback, e.g., from issuer to the PTD, to the card, and back to PTD and issuer. Such feedback can be very important and used to validate the entire system security. 
         [0081]    An advantage of the present embodiment in using optical transmission is that it is not susceptible to surreptitious acquisition or interrogation typical of NFC cards. The magnetic interface card will not be “awake” until it is swiped, or a swipe sensor is pressed. By pressing the magnetic interface card against the screen of a PTD, the magnetic interface card will first transmit data, and then it will “look” for optical communications within a certain period of time, receive any data, and then go back to sleep. The optical emissions must be within a certain intensity and baud rate, and filters can be used for spectral discrimination. 
         [0082]    In general, embodiments of the present invention include both device and system applications. The magnetic interface cards are fairly “dumb” interfaces, e.g., between a powerful smartphone and more than forty million magnetic swipe terminals throughout the world. Each interface card acts as an extension of the smartphone, to bring to bear all the great financial applications available on smartphones and not available to unmodified POS terminals. The magnetic interface cards can communicate to the user with tones, beeps or even synthesized stored voice statements. These are receivable by smartphones via their built-in microphones. 
         [0083]    A smartphone app can be included to program the magnetic interface card and to “listen” for encoded tones, or synthesized voices. It can be used to acknowledge successful data communications, maintenance, monitoring data, battery condition, etc. 
         [0084]    Although particular embodiments of the present invention have been described and illustrated, such is not intended to limit the invention. Modifications and changes will no doubt become apparent to those skilled in the art, and it is intended that the invention only be limited by the scope of the appended claims.