US5644636A
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US
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Method and apparatus for securing data stored in semiconductor memory cells
Assignee: XTec Inc
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Filing: 1994-12-30
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Granted: 1997-07-01
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Expires: 2014-12-30
Abstract
Abstract A method and apparatus for securing data stored in semiconductor memory cells of a semiconductor device is described. A reference fingerprint corresponding to numerical representations of a measurement of the levels of charges trapped in the memory cells is generated and stored. The measurement is performed immediately after programming data to the memory cells. The reference fingerprint is then compared to a measurement of numerical representations of the levels of charges trapped in the memory cells of a memory device that has been presented to a reader. If a match occurs, then the data stored in the memory device is authenticated. An intentional offset error voltage may be applied when writing data to the memory cells to enhance the security of the data. The reference fingerprint may also be encrypted prior to storage for added security. Lastly, fuzzy logic techniques may be used to compensate for environmental and hardware related fluctuations in the levels of trapped charges of the programmed memory cells.
Inventors
- 👤 Alberto J. Fernandez
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:34
CPC Classifications
G; G11; G11C; G11C16/00; G11C16/02; G11C16/06; G11C16/22
Claims Analysis
Total Claims: 40
Claim 1
Independent Claim
81 words
A method for securing data in a semiconductor memory cell of a semiconductor memory device, comprising the steps of: programming data in the memory cell by applying a voltage which causes charges to be trapped in the memory cell; making a measurement of the level of trapped charges in the memory cell after the memory cell is programmed; generating a numerical representation of the level of trapped charges as a reference fingerprint of the memory cell; and storing the numerical representation.
Claim 2
Independent Claim
81 words
A method for securing data in a semiconductor memory cell of a semiconductor memory device, comprising the steps of: programming data in the memory cell by applying a voltage which causes charges to be trapped in the memory cell; making a measurement of the level of trapped charges in the memory cell after the memory cell is programmed; generating a numerical representation of the level of trapped charges as a reference fingerprint of the memory cell; and storing the numerical representation.
Claim 3
Dependent Claim
16 words
The method of claim 1, wherein the numerical representation is written onto the semiconductor memory device.
Claim 4
Dependent Claim
15 words
The method of claim 1, wherein the numerical representation is written to an external device.
Claim 5
Dependent Claim
12 words
The method of claim 3, wherein the external device is a database.
Claim 6
Dependent Claim
19 words
The method of claim 1, wherein the step of generating the numerical representation further comprises: encrypting the numerical representation.
Claim 7
Independent Claim
124 words
A method for authenticating data stored in a plurality of semiconductor memory cells in a semiconductor memory device, comprising the steps of: programming data to the plurality of memory cells by applying a plurality of voltages such that charges are trapped in each of the memory cells; measuring the levels of the trapped charges in the plurality of memory cells after the memory cells are programmed; generating numerical representations of the measured levels of trapped charges as a reference fingerprint; storing the reference fingerprint; and, comparing the reference fingerprint to numerical representations of a subsequent measurement of the levels of trapped charges in the memory cells defining an authentication fingerprint, in order to determine whether the data stored in the memory cells is authentic.
Claim 8
Independent Claim
124 words
A method for authenticating data stored in a plurality of semiconductor memory cells in a semiconductor memory device, comprising the steps of: programming data to the plurality of memory cells by applying a plurality of voltages such that charges are trapped in each of the memory cells; measuring the levels of the trapped charges in the plurality of memory cells after the memory cells are programmed; generating numerical representations of the measured levels of trapped charges as a reference fingerprint; storing the reference fingerprint; and, comparing the reference fingerprint to numerical representations of a subsequent measurement of the levels of trapped charges in the memory cells defining an authentication fingerprint, in order to determine whether the data stored in the memory cells is authentic.
Claim 9
Dependent Claim
48 words
The method of claim 6, wherein fuzzy logic techniques are utilized to generate the reference fingerprint and the authentication fingerprint to compensate for variations in the numerical representations of the measured levels of trapped charges in the memory cells which are caused by environmental and hardware related factors.
Claim 10
Dependent Claim
16 words
The method of claim 6, wherein the reference fingerprint is written onto the semiconductor memory device.
Claim 11
Dependent Claim
15 words
The method of claim 6, wherein the reference fingerprint is written to an external device.
Claim 12
Independent Claim
12 words
The method of claims 9, wherein the external device is a database.
Claim 13
Dependent Claim
19 words
The method of claim 6, wherein the step of generating the reference fingerprint further comprises: encrypting the reference fingerprint.
Claim 14
Dependent Claim
27 words
The method of claim 6, wherein the step of programming the memory cells further comprises: introducing intentional random offsets to each of the applied plurality of voltages.
Claim 15
Dependent Claim
160 words
A secure semiconductor memory cell apparatus comprising: first and second semiconductor cells; a data out line selectively connected to the first and second semiconductor memory cells upon which voltages are applied for programming data to the first and second semiconductor memory cells, causing charges to be trapped in the first and second memory cells; and an analog out line selectively connected to the first and second semiconductor memory cells for selective connection to a measurement apparatus for making an analog measurement of the levels of trapped charges in the first and second memory cells, wherein said second memory cells are utilized for storing a reference fingerprint generated from numerical representations of the levels of trapped charges measured in the first memory cells, such that a comparison of the stored reference fingerprint to numerical representations of a subsequent measurement of the levels of trapped charges in the first memory cells provides for authenticating the data stored in the first memory cells.
Claim 16
Dependent Claim
160 words
A secure semiconductor memory cell apparatus comprising: first and second semiconductor cells; a data out line selectively connected to the first and second semiconductor memory cells upon which voltages are applied for programming data to the first and second semiconductor memory cells, causing charges to be trapped in the first and second memory cells; and an analog out line selectively connected to the first and second semiconductor memory cells for selective connection to a measurement apparatus for making an analog measurement of the levels of trapped charges in the first and second memory cells, wherein said second memory cells are utilized for storing a reference fingerprint generated from numerical representations of the levels of trapped charges measured in the first memory cells, such that a comparison of the stored reference fingerprint to numerical representations of a subsequent measurement of the levels of trapped charges in the first memory cells provides for authenticating the data stored in the first memory cells.
Claim 17
Dependent Claim
15 words
The apparatus of claim 13, wherein the memory cells are included in an integrated circuit.
Claim 18
Dependent Claim
59 words
The apparatus of claim 13, further comprising: an analog to digital converter comprising an input and an output, wherein the analog out line connects the input to the memory cells, and wherein the analog to digital converter converts any analog signals detected on the analog out line to digitized numerical representations and provides said numerical representations at the output.
Claim 19
Dependent Claim
20 words
The apparatus of claim 15, wherein the microcontroller and the analog to digital converter are fabricated on an integrated circuit.
Claim 20
Dependent Claim
106 words
The apparatus of claim 15, further comprising: a microcontroller for providing applied voltages on the data out line for programming the first memory cells and the second memory cells, wherein the microcontroller further comprises a processor and a memory, wherein the processor stores in the memory the numerical representations of the measured levels of trapped charges of the first memory cells, and wherein the processor generates the reference fingerprint from the stored numerical representations obtained from the measurements involving the first memory cells and regenerates the reference fingerprint from measurements of the second memory cell, if the reference fingerprint is stored in the second memory cells.
Claim 21
Dependent Claim
26 words
The apparatus of claim 17, wherein the processor provides voltage signals on the data out line for writing the reference fingerprint to the second memory cells.
Claim 22
Dependent Claim
31 words
The apparatus of claim 17, wherein the processor provides voltage signals at an input and output port of the microcontroller for purposes of storing the reference fingerprint on an external device.
Claim 23
Dependent Claim
12 words
The apparatus of claim 19, wherein the external device is a database.
Claim 24
Dependent Claim
42 words
The apparatus of claim 17, wherein the processor compares the reference fingerprint to numerical representations of a subsequent measurement of the trapped charge levels in the first memory cells to determine the authenticity of the data stored in the first memory cells.
Claim 25
Dependent Claim
24 words
The apparatus of claim 17, wherein the processor introduces an intentional random offset to the respective voltages applied for programming the first memory cells.
Claim 26
Dependent Claim
14 words
The apparatus of claim 17, wherein the processor encrypts and stores the reference fingerprint.
Claim 27
Dependent Claim
26 words
The apparatus of claim 23, wherein the processor provides voltage signals on the data out line for writing the reference fingerprint to the second memory cells.
Claim 28
Dependent Claim
30 words
The apparatus of claim 23, wherein the processor provides voltage signals at an input and output port of the microcontroller for storage of the reference fingerprint on an external device.
Claim 29
Dependent Claim
23 words
The apparatus of claim 17, wherein the microcontroller, the analog to digital converter and the memory cells are fabricated on an integrated circuit.
Claim 30
Independent Claim
167 words
A method for authenticating data stored in a plurality of first semiconductor memory cells in a first semiconductor memory device to prevent counterfeiting comprising the steps of: programming the data to the plurality of first memory cells by applying a plurality of voltages, respectively, which cause charges to be trapped in the plurality of the first memory cells; measuring the levels of the trapped charges in the plurality of first memory cells after programming the first memory cells; generating numerical representations of the measured levels of trapped charges as a reference fingerprint; measuring the levels of the trapped charges in a plurality of second memory cells in a second semiconductor memory device which is presented to a semiconductor memory device reader; generating numerical representations of the measured levels of trapped charges in the second memory cells as an authentication fingerprint; retrieving the stored reference fingerprint; and comparing the reference fingerprint to the authentication fingerprint to determine whether the data stored in the second memory cells are authentic.
Claim 31
Independent Claim
167 words
A method for authenticating data stored in a plurality of first semiconductor memory cells in a first semiconductor memory device to prevent counterfeiting comprising the steps of: programming the data to the plurality of first memory cells by applying a plurality of voltages, respectively, which cause charges to be trapped in the plurality of the first memory cells; measuring the levels of the trapped charges in the plurality of first memory cells after programming the first memory cells; generating numerical representations of the measured levels of trapped charges as a reference fingerprint; measuring the levels of the trapped charges in a plurality of second memory cells in a second semiconductor memory device which is presented to a semiconductor memory device reader; generating numerical representations of the measured levels of trapped charges in the second memory cells as an authentication fingerprint; retrieving the stored reference fingerprint; and comparing the reference fingerprint to the authentication fingerprint to determine whether the data stored in the second memory cells are authentic.
Claim 32
Dependent Claim
17 words
The method of claim 27 wherein the reference fingerprint is written onto the first semiconductor memory device.
Claim 33
Dependent Claim
15 words
The method of claim 27, wherein the reference fingerprint is written onto an external device.
Claim 34
Dependent Claim
12 words
The method of claim 29, wherein the external device is a database.
Claim 35
Dependent Claim
19 words
The method of claim 27, wherein the step of storing the reference fingerprint further comprises: encrypting the reference fingerprint.
Claim 36
Dependent Claim
29 words
The method of claim 27, wherein the step of programming the first memory cells further comprises: introducing an intentional random offset to each of the applied plurality of voltages.
Claim 37
Independent Claim
91 words
A method for securing data in a semiconductor memory cell of a semiconductor memory device, comprising the steps of: programming data in the memory cell by applying a voltage which causes charges to be trapped in the memory cell, said step of programming data in the memory cell further comprising introducing an intentional random offset to the applied voltage; measuring the level of trapped charges in the memory cell after the memory cell is programmed; generating a numerical representation of the level of trapped charges measured; and storing the numerical representation.
Claim 38
Independent Claim
91 words
A method for securing data in a semiconductor memory cell of a semiconductor memory device, comprising the steps of: programming data in the memory cell by applying a voltage which causes charges to be trapped in the memory cell, said step of programming data in the memory cell further comprising introducing an intentional random offset to the applied voltage; measuring the level of trapped charges in the memory cell after the memory cell is programmed; generating a numerical representation of the level of trapped charges measured; and storing the numerical representation.
Claim 39
Independent Claim
112 words
A method for securing data in a semiconductor memory cell of a semiconductor memory device, comprising the steps of: programming data in the memory cell by applying a voltage which causes charges to be trapped in the memory cell; measuring the level of trapped charges in the memory cell after the memory cell is programmed; generating a numerical representation of the level of trapped charges measured; storing the numerical representation; comparing the stored numerical representation to a numerical representation of a subsequent measurement of the level of trapped charges in the memory cell; and authenticating the data stored in the memory cell if the stored numerical representation matches the second numerical representation.
Claim 40
Independent Claim
112 words
A method for securing data in a semiconductor memory cell of a semiconductor memory device, comprising the steps of: programming data in the memory cell by applying a voltage which causes charges to be trapped in the memory cell; measuring the level of trapped charges in the memory cell after the memory cell is programmed; generating a numerical representation of the level of trapped charges measured; storing the numerical representation; comparing the stored numerical representation to a numerical representation of a subsequent measurement of the level of trapped charges in the memory cell; and authenticating the data stored in the memory cell if the stored numerical representation matches the second numerical representation.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-06-30 | 2000-12-30 | 2001-07-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-06-30 | 2004-12-30 | 2005-07-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-06-30 | 2008-12-30 | 2009-07-01 | $7700.00 | Window Closed / Lapsed |