Registers – Coded record sensors – Particular sensor structure
Reexamination Certificate
2003-05-01
2004-12-14
Stcyr, Daniel (Department: 2876)
Registers
Coded record sensors
Particular sensor structure
C235S493000
Reexamination Certificate
active
06830183
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a new and improved device for reading, modifying and writing information on a storage medium, and more particularly to a method and apparatus for authenticating the medium and information stored on the medium by performing spatial measurements using a divided track transducer head.
2. Description of the Related Art
In many instances, it is desirable to provide a method and apparatus for storing and transporting information. In particular, many ways have been devised for encoding information on a medium which can be conveniently carried about by a person during the normal course of business. For example, credit cards, debit cards, electronic purse cards, decrementing value cards, checks, driver's licenses, identification cards, access control cards, magnetic tapes and disc, and many other such media which are small enough to be conveniently carried in a person's handbag or wallet are ubiquitous today. However, in many of the applications in which these media are intended to be used, security is an important concern. That is, it is important that only authorized organizations are capable of modifying the information stored thereon. One very common way for information to be stored on such a medium is by magnetically encoding the information.
Techniques for encoding information on magnetic media have been available for many years and are now relatively inexpensive. Other techniques include optical storage techniques and printed information using relative light and dark areas, such as the uniform purchasing codes (UPCs) which are printed on the packaging of most products today. For simplicity sake, only magnetic techniques are discussed in detail. However, it will be understood that the following discussion applies equally well to other techniques for storing information.
Cards which have a magnetic stripe attached thereto are ubiquitous in modem society. That is, nearly everyone carries one of the following cards, each of which typically has a magnetic stripe attached thereto: credit cards, bank cards (ATM cards), debit cards, identification cards, driver's licenses, security access cards, check cashing cards, etc. Data is typically represented on magnetic medium by polarizing magnetic particles of the magnetic medium in one of two magnetic states. When magnetic medium is swiped across an inductive read head the moving magnetic field induces a magnetic field in the head core structure which in turn induces an electric current in the head read coil.
Alternately the change in magnetic field states can be directly measured using a magnastritive (MR) head. Either voltage waveform is converted to pulses with a peak detector. When reading the data from the magnetic medium, transitions between the two magnetic field states induce a voltage in the magnetic head read coil. A peak detector circuit translates this voltage into binary states. The head coil voltage is amplified by a differential amplifier then a dual edge peak detector switches between ground and VCC states each time the input changes polarity. The output of the peak detector is buffered by comparator with hysteresis to improve noise immunity. The states generated are detected as pulse durations; one pulse duration is approximately double in length to the other. The longer pulse duration represents a bit cell time and data value of zero, two consecutive pulse of the shorter duration also represent bit cell and in this case a data bit value of one.
Magnetically encoded information can easily be copied or transferred from one magnetic information storage medium to another. Unless special provisions are made to secure the information, information can be altered and re-encoded back onto the original medium or a duplicate of the original medium. If the information is used in a system for organizing financial transactions or for personal identification, then such copying, altering, and duplicating makes the person for whom the information was intended, and the organization who operates the system, vulnerable to fraud.
For example, if a magnetic stripe affixed to a debit card is used to indicate how much money is currently in a personal account, modifications to that information can be used to increase the apparent balance in order to purchase goods which have a higher value than actually exists in the account. Additionally, if the card is duplicated, the same account could be used by more than one person. It should be clear that fraud could occur in a number of ways if sensitive information is not properly secured. In fact fraud due to copying and modification of information magnetically encoded on portable media, such as magnetic stripe cards, is growing at an alarming rate. For example, it is estimated that the cost of fraud to the credit card industry alone will exceed one billion dollars per year before the end of the century.
A number of techniques have been proposed to authenticate both the information, and the medium on which the information is stored (commonly referred to as a “document”), in order to prevent fraud. For example, U.S. Pat. No. 4,023,204 issued to Lee, discloses using a unique magnetic coating with pre-determined alignment of the magnetic particles as the basis for authentication measurements. Thus, a code which can not be altered can be implanted into the document to authenticate the document. U.S. Pat. No. 5,336,871 issued to Colgate, discloses the use of a hologram to authenticate a substrate on which a magnetic stripe is affixed. U.S. Pat. No. 5,354,097 issued to Tel, discloses the use of overlays to authenticate information.
U.S. Pat. No. 4,628,195, issued to Baus, discloses generating a security code number determined by the relative spatial positions of corresponding data in two different forms of encoded data on a card. In particular, Baus discloses using a conventional magnetic stripe as the first means for encoding data, and using embossed characters as a second means for encoding data. The relative position of the magnetic information with respect to the embossed information is used ti) generate a numeric security code. In addition, dyes or absorbers incorporated in a magnetic stripe have been used to attempt to encode a security identifier into the document on which the information resides.
However, each of these methods requires the use of special materials in the security process. Accordingly, none of the old documents would be usable, and all of the documents currently in use would have to he recalled and reissued using the new security process. Recalling and replacing all of the documents that are currently in use would be very costly and has hampered the widespread implementation of such technologies.
In the case of the technique disclosed by Baus, both an automatic reading method for reading the magnetic stripe, and also an automatic reading method for reading the embossed characters, are required. Therefore, there are two sub-systems required by this technique. Furthermore, readers used at the point-of-sale must preserve the spatial relationship between the magnetically stored information and the embossed characters. This is a cumbersome and expensive process which is very difficult to perform at the point-of-sale. Accordingly, it may be difficult to maintain reliable operation of systems which conform to the Baus technique.
Others have attempted to overcome the above limitations when the document is a magnetic medium by employing characteristics of the magnetic signals used to store the information to authenticate both the document and the information stored thereon. For example, U.S. Pat. No. 4,837,426 issued to Pease, discloses a method for authenticating documents by analyzing the amplitude of the magnetic signals. U.S. Pat. Nos. 5,408,505 and 5,428,683, each issued to Indeck, et al. disclose a method for authenticating documents using “noise” in the saturation region of the magnetic data. U.S. Pat. Nos. 5,235,166, and 5,430,279, each issued to Fernandez, and U.S. Pat. No. 5,254,843 iss
Mos Robert J.
von Mueller Clay
Clarke Richard D.
Semtek Innovative Solutions, Inc.
Stcyr Daniel
LandOfFree
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