Patent US5235166A successfully refreshed from Google Patents.
US5235166A
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US
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Data verification method and magnetic media therefor
Assignee: XTec Inc
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Filing: 1991-02-14
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Granted: 1993-08-10
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Expires: 2011-02-14
Abstract
Abstract Magnetic media containing data and method for data verification are disclosed. The data verification method utilizes the relative position of specific features of magnetic media signals, such as, peak zero crossings, the ratio of preselected amplitudes, the locii of preselected points along the signal, the RMS value of the waveform and the like. In the preferred embodiment, the ratio of the separation of adjacent pulses in the signal is employed. The deviation of the precise location of the placement of the peak points in the signal waveform is referred to as "jitter". This "jitter" is enhanced to provide a pattern of "jitter" or a magnetic "signature" that is random, non-reproducible and that can be used to positively identify a particular specimen of magnetic media and the associated data. The magnetic jitter pattern or security signature can be separate from or an integral part of the data recorded on the magnetic media. The data verification method and magnetic media have particular application in the field of credit cards.
Inventors
- 👤 Alberto J. Fernadez
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 22:24
CPC Classifications
G; G06; G06K; G06K5/00; G06K5/02; G06K1/00; G06K1/12; G06K1/125; G06K5/04; G06K7/00; G06K7/08; G06K7/082; G06K7/083; G06K7/084
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
98 words
A method for generating a magnetic security signature on a magnetically recordable medium comprising the steps of: A. producing a data representative signal to be recorded on said magnetically recordable medium; and, B. recording the data representative signal on the magnetically recordable medium while controlling the rate of change of the recording signal to extend the length of time that the magnetic flux transition remains on the most curved portion of the hysteresis loop of the magnetically recordable medium, whereby the magnetic security signature is enhanced by increasing the hysteresis during the recording of the data representative signal.
Claim 2
Independent Claim
98 words
A method for generating a magnetic security signature on a magnetically recordable medium comprising the steps of: A. producing a data representative signal to be recorded on said magnetically recordable medium; and, B. recording the data representative signal on the magnetically recordable medium while controlling the rate of change of the recording signal to extend the length of time that the magnetic flux transition remains on the most curved portion of the hysteresis loop of the magnetically recordable medium, whereby the magnetic security signature is enhanced by increasing the hysteresis during the recording of the data representative signal.
Claim 3
Dependent Claim
47 words
The method of claim 1 further comprising the steps of: A. determining a pattern of jitter in the recorded data representative signal; B. generating data representative of said pattern of jitter; and C. recording on said magnetically recordable medium said data representative of said pattern of jitter.
Claim 4
Independent Claim
129 words
A method for identifying magnetically recordable medium having a data representative signal recorded thereon, said method comprising the steps of: A. determining an existing pattern of jitter by precisely determining relative time positions of specific signal variations in at least a portion of the recorded data representative signal; B. generating data representative of said existing pattern of jitter based on the determination of said relative time positions; C. determining subsequently a subsequently existing pattern of jitter in said at least a portion of the recorded data representative signal; D. generating data representative of said subsequently existing patter of jitter; E. comparing the data representative of said existing pattern of jitter and data representative of said subsequently existing pattern of jitter; and, F. utilizing the results of said data comparison,
Claim 5
Independent Claim
129 words
A method for identifying magnetically recordable medium having a data representative signal recorded thereon, said method comprising the steps of: A. determining an existing pattern of jitter by precisely determining relative time positions of specific signal variations in at least a portion of the recorded data representative signal; B. generating data representative of said existing pattern of jitter based on the determination of said relative time positions; C. determining subsequently a subsequently existing pattern of jitter in said at least a portion of the recorded data representative signal; D. generating data representative of said subsequently existing patter of jitter; E. comparing the data representative of said existing pattern of jitter and data representative of said subsequently existing pattern of jitter; and, F. utilizing the results of said data comparison,
Claim 6
Dependent Claim
54 words
The method of claim 3 wherein said data representative of said existing pattern of jitter is recorded on the particular magnetically recordable medium so that the comparison of Step E is made between the recorded data representative of said existing pattern of jitter and said data representative of said subsequently existing pattern of jitter.
Claim 7
Independent Claim
145 words
A method for generating a magnetic security signature on a magnetically recordable medium comprising the steps of: A. pre-biasing the magnetically recordable medium by recording a pre-bias signal thereon that produces random saturated flux transitions on the magnetically recordable medium; B. recording a data representative signal on the pre-biased magnetically recordable medium to produce a composite signal containing jitter with at least a portion of the jitter being attributable to the effect of the pre-biasing of the magnetically recordable medium; and C. controlling during recording the rate of change of the recording data representative signal to extend the length of time that the magnetic flux transition remains on the most curved portion of the hysteresis loop of the magnetically recordable medium to further enhance the jitter, whereby the magnetic security signature is enhanced by increasing the hysteresis during the recording of the data representative signal.
Claim 8
Independent Claim
145 words
A method for generating a magnetic security signature on a magnetically recordable medium comprising the steps of: A. pre-biasing the magnetically recordable medium by recording a pre-bias signal thereon that produces random saturated flux transitions on the magnetically recordable medium; B. recording a data representative signal on the pre-biased magnetically recordable medium to produce a composite signal containing jitter with at least a portion of the jitter being attributable to the effect of the pre-biasing of the magnetically recordable medium; and C. controlling during recording the rate of change of the recording data representative signal to extend the length of time that the magnetic flux transition remains on the most curved portion of the hysteresis loop of the magnetically recordable medium to further enhance the jitter, whereby the magnetic security signature is enhanced by increasing the hysteresis during the recording of the data representative signal.
Claim 9
Independent Claim
180 words
A method for generating a magnetic security signature on a magnetically recordable medium comprising the steps of: A. pre-biasing the magnetically recordable medium by recording a pre-bias signal thereon that produces random saturated flux transitions on the magnetically recordable medium; B. recording a data representative signal on the pre-biased magnetically recordable medium to produce a composite signal containing jitter with at least a portion of this jitter being attributable to the effect of the pre-biasing of the magnetically recordable medium; C. controlling during recording the rate of change of the recording data representative signal to extend the length of time that the magnetic flux transition remains on the most curved portion of the hysteresis loop of the magnetically recordable medium to further enhance the jitter; D. determining a pattern of the jitter in the composite signal; E. generating data representative of said pattern of jitter; and F. recording on said magnetically recordable medium said data representative of said pattern of jitter, whereby the magnetic security signature is enhanced by increasing the hysteresis during the recording of the data representative signal.
Claim 10
Independent Claim
180 words
A method for generating a magnetic security signature on a magnetically recordable medium comprising the steps of: A. pre-biasing the magnetically recordable medium by recording a pre-bias signal thereon that produces random saturated flux transitions on the magnetically recordable medium; B. recording a data representative signal on the pre-biased magnetically recordable medium to produce a composite signal containing jitter with at least a portion of this jitter being attributable to the effect of the pre-biasing of the magnetically recordable medium; C. controlling during recording the rate of change of the recording data representative signal to extend the length of time that the magnetic flux transition remains on the most curved portion of the hysteresis loop of the magnetically recordable medium to further enhance the jitter; D. determining a pattern of the jitter in the composite signal; E. generating data representative of said pattern of jitter; and F. recording on said magnetically recordable medium said data representative of said pattern of jitter, whereby the magnetic security signature is enhanced by increasing the hysteresis during the recording of the data representative signal.
Claim 11
Independent Claim
73 words
A method for generating a magnetic security signature on a magnetically recordable medium comprising the steps of: A. determining a pattern of jitter by precisely determining relative time positions of specific signal variations in a recorded data representative signal; B. generating data representative of said pattern of jitter based on the determination of said relative time positions; and C. recording on said magnetically recordable medium said data representative of said pattern of jitter.
Claim 12
Independent Claim
73 words
A method for generating a magnetic security signature on a magnetically recordable medium comprising the steps of: A. determining a pattern of jitter by precisely determining relative time positions of specific signal variations in a recorded data representative signal; B. generating data representative of said pattern of jitter based on the determination of said relative time positions; and C. recording on said magnetically recordable medium said data representative of said pattern of jitter.
Claim 13
Independent Claim
141 words
A method for identifying magnetically recordable medium having a first data representative signal recorded thereon, said method comprising the steps of: A. determining an existing pattern of jitter by precisely determining relative time positions of specific signal variations in at least a portion of the magnetically recordable medium in which the first recorded data representative signal is recorded; B. generating data representative of said existing pattern of jitter based on the determination of said relative time positions; C. writing a second data representative signal over the first data representative signal in said portion of the magnetically recordable medium to reflect a change of the data; D. determining subsequent to the writing of said second data a subsequently existing pattern of jitter in said portion of the magnetically recordable medium; and E. generating data representative of said subsequently existing pattern of jitter.
Claim 14
Independent Claim
141 words
A method for identifying magnetically recordable medium having a first data representative signal recorded thereon, said method comprising the steps of: A. determining an existing pattern of jitter by precisely determining relative time positions of specific signal variations in at least a portion of the magnetically recordable medium in which the first recorded data representative signal is recorded; B. generating data representative of said existing pattern of jitter based on the determination of said relative time positions; C. writing a second data representative signal over the first data representative signal in said portion of the magnetically recordable medium to reflect a change of the data; D. determining subsequent to the writing of said second data a subsequently existing pattern of jitter in said portion of the magnetically recordable medium; and E. generating data representative of said subsequently existing pattern of jitter.
Claim 15
Dependent Claim
57 words
The method of claim 8 further comprising the steps of writing an additional data representative signal over the previously existing data signal each time a change of data occurs; F. determining subsequent to each said writing of additional data a new existing pattern of jitter; and G. generating representative data for each new existing pattern of jitter.
Claim 16
Dependent Claim
32 words
The method of claim 8 further comprising the step of encoding a signal representative said data representative of said existing pattern of jitter on a second portion of the magnetically recordable medium.
Claim 17
Dependent Claim
21 words
The method of claim 8 further comprising the step of encoding said data representative of said subsequently existing pattern of jitter.
Claim 18
Dependent Claim
40 words
The method of claim 10 further comprising the steps of redetermining the existing pattern of jitter prior to writing said second data representative signal; retrieving the encoded signal; and comparing the encoded signal and the redetermined existing pattern of jitter.
References Cited (Backward Citations)
US4650978A
Cited
US4837426A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-08-09 | 1997-02-08 | 1997-08-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-08-09 | 2001-02-08 | 2001-08-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-08-09 | 2005-02-08 | 2005-08-10 | $7700.00 | Window Closed / Lapsed |