USO0RE43658E
(19) United States (12) Reissued Patent Guthery (54)
(10) Patent Number: US (45) Date of Reissued Patent:
Sep. 11, 2012
ANALOG PHYSICAL SIGNATURE DEVICES
7,280,970 B2 *
10/2007
Tamir et a1. ................. .. 704/273
AND METHODS AND SYSTEMS FOR USING SUCH DEVICES TO SECURE THE USE OF COMPUTER RESOURCES
7,299,189 B1 *
11/2007
Sato .......... ..
7,415,126 B2* 7,454,620 B2 *
2002/0154893 A1 2005/0203841 A1* 2006/0095778 A1*
(75) Inventor: Scott B. Guthery, Chestnut Hill, MA (Us)
11/2008
704/500
382/100
Bruekers et a1. ............ .. 713/176
10/2002 Tanaka et a1. 9/2005 5/2006
Hoffman et a1. .............. .. 705/39 He et a1. ...................... .. 713/180
Ravikanth Pappu et al., “Physical One-Way Functions”, Science Magazine, v01. N0. 297, pp. 2026-2030, Sep. 20, 2002.
(Continued)
(21) Appl. No.: 12/985,302 Filed:
8/2008 Breed et a1.
OTHER PUBLICATIONS
(73) Assignee: Momin Development Fund LLC, Wilmington, DE (U S)
(22)
RE43,658 E
Jan. 5, 2011
Primary Examiner * Samson Lemma
(Under 37 CFR 1.47)
(57)
Related US. Patent Documents
Jan. 6, 2009
A method for binding a computer program to an analog physi cal signature device to form an interactive system for control ling the use of the computer program, the method comprising
Appl. No.:
10/700,369
the steps of providing instructions comprising the computer
Filed:
Nov. 3, 2003
Reissue of:
(64)
ABSTRACT
Patent No.:
7,475,255
Issued:
program, the instructions implementing an intended func
tionality, providing the analog physical signature device to
(51)
Int. Cl.
Field of Classi?cation Search ................ .. 713/176,
Which the computer program is to be bound, the analog physi cal signature device being operative, in response to an analog input, to transform the analog input into a consequent, depen dent analog output, and replacing at least one code segment of
713/168,180,187
the instructions representing a program expression, With an
H04L 9/00
(52) (58)
(2006.01)
US. Cl. ....................... .. 713/187; 713/168; 713/180
alternative code segment, the alternative code segment de?n ing a predetermined digital input that is causally related to a predetermined analog input by means of the interactive sys tem, the alternative code segment being operative, When encountered during execution of the instructions comprising the computer program, to cause the predetermined analog input to be communicated to the bound analog physical sig
See application ?le for complete search history. (56)
References Cited U.S. PATENT DOCUMENTS
3,829,838 4,412,208 4,599,489 4,763,066 4,924,175 5,123,045 5,570,091 5,574,787
A A A A A A A A
5,596,280 A
6,246,803 6,327,378 6,327,652 6,584,214 7,146,498
*
8/1974
Lewis et a1. ................. .. 345/419
10/1983 Akazawa et a1.
7/1986 Cargile *
8/1988
nature device by means of the interactive system, the bound
Yeung et a1. ............... .. 324/731
analog physical signature device being operative to transform
5/ 1990 Clinton
the predetermined analog input to a consequent, dependent analog output that is causally related to a consequent, depen dent digital output by means of the interactive system, the alternative code segment being operative to perform program
6/1992 Ostrovsky et a1. 10/1996 Noro et a1. *
11/1996
Ryan ........................... .. 380/201
1/1997 Riggio 6/2001
Gauch ......................... .. 382/276
functionality dependent upon the predetermined digital input and the consequent, dependent digital output.
12/2001 Ball 12/2001 England et a1. 6/2003 Pappu et a1. 12/2006
79 Claims, 11 Drawing Sheets
Takechi et a1. .............. .. 713/158
mm : prognm compuhllull or program wane-ma '
constant value 'c‘
m in: meer 01
the computer
Sand 91 to ma analog PhySlcal \gnmula devlm
mm. mm vow 9‘ than in: annlng phydul sign-mm
<— 305
devlee
300 Retrieve a wound waillnl w
m". "Ii memory m We
mpmer (.1 required)
End the wgmm computation w: ng [woman I
not sum
m! mmmnar
'
my m
US RE43,658 E Page 2 OTHER PUBLICATIONS
Fox, Barry, “‘Subversive’ code could kill off software piracy” http://
WWW.newscientist.con1/news/newsjsp?id:ns99994248; Blaise Gassend et al., “Controlled Physrcal Random Functions”Massachusetts Institute of Technology, Laboratory for Computer Sci ence, Cambridge, MA, Dec. 2002.
publication date Oct, 10, 2003; Printed date Apr‘ 26, 2004‘ * Cited by examiner
Original
US. Patent
Sep. 11,2012
Sheet 1 0f 11
US RE43,658 E
10
Relatively Complex Immutable
Inhomogeneous Material
11 12
14
Figure 1
US. Patent
Sep. 11,2012
Sheet 2 0f 11
US RE43,658 E
Produce Known Light Wave
l Input Known Light Wave to the Analog Physical +——-54 Signature Device at Interface Point A
I Detect and Store Output Light Wave at Interface <—————56 Point 8 of the Analog
Physical Signature Device
l Correlate Input and Output Light Waves to 4—58 Produce Unique
Signature of Analog
Physical Signature Device
Figure 2
50
US. Patent
Sep. 11,2012
Sheet 3 0f 11
Produce Known Sonic Waveform
US RE43,658 E
4————62
l Input Known Sonic Waveform to the Analog Physical Signature <_—_—" 64 Device at Interface Point A
l
60
Detect and Store Output Sonic Waveform at
Interface Point 8 of the
Analog Physical Signature Device
l
Correlate Input and Output Sonic Waveforms to Produce Unique
Signature of Analog
Physical Signature Device
Figure 3
4—.— 66
US. Patent
Sep. 11,2012
Sheet 4 0f 11
US RE43,658 E
Re?ective Inhomogeneity
20
10
12 Input Light
Wave
i
/ 1
B
in
Q
22 Color Filter inhomogeneity
Figure 4
Output
:> Light Wave
US. Patent
Sep. 11,2012
Sheet 5 0f 11
US RE43,658 E
14
\
Input Light
Output Light Wave
Wave
Light Wave
Detecting Means
Light Wave
Generating means
u 30
26
/
Glass
lnhomogeneity
ii
Surface lnhomogeneity
Figure 5
Metailic Backing Inhomogeneity
US. Patent
Sep. 11,2012
Sheet 6 0f 11
US RE43,658 E
10
/
14 1/
11 ____’
231
.E
> Output Sonic
A ——>
/
Input Sonic Waveform
Figure 6
aveform
US. Patent
Sep. 11,2012
Sheet 7 0f 11
US RE43,658 E
Begin a program computation or program branching involving a constant value or
4—— Step 1
current variable value
l Retrieve the constant value or
current variable value from the memory of the computer
4-— Step 2
l
Use the constant value or current variable value in a
computation or branching of the computer program
4—— Step 3
l
End the program computation or program branching involving a constant value or current variable value
4— Step 4
Figure 7 (Prior Art)
US. Patent
Sep. 11,2012
Sheet 8 0f 11
US RE43,658 E
Begin a program computation or program branching involving a constant value 'c‘ not stored in the memory of
+— 302
the computer
t Retrieve a predetermined
input 'x' from the memory of the computer
<— 304
t Send 'x' to the analog physical signature device
4— 306
t Receive output value 'y' from
the analog physical signature
4— 308
device
+
300
Retrieve a second constant 'a'
from the memory of the
4— 310
computer (if required)
Set 0* = T(y,a)
eg
4-— 312
c* = y + a
it Use 'c*' as the value of the constant 'c' in the program computation or program
<——— 314
branching
t End the program computation or program branching involving a constant value 'c' not stored in the memory of
the computer'
Figure 8
4— 316
US. Patent
Sep. 11,2012
Begin a program computation or program branching involving the current value of a program variable 'x'
Sheet 9 0f 11
US RE43,658 E
<—-— 402
l Send the current value of 'x‘ to
the analog physical signature
4—— 404
device
t Receive output value 'y' from the analog physical signature
4—— 406
device
+ Set x* = T(x, y)
400 +--— 408
l Use 'x‘“ as the current value of
the variable 'x' in the program computation or program
<—— 410
branching
t End the program computation or program branching involving the current value of a program variable 'x'
Figure 9
*— 412
US. Patent
Sep. 11,2012
Sheet 10 0f 11
US RE43,658 E
Select an appearance 0?? program constant 'c', or program varlab e 202 —>
or program function 'x', in the individual computer program to be
replaced
V
Determine the output of the individual analog physical signature 204 —>
device when provided with the current value of 'x‘ as an input where G(x)
describes the functioning of the individual analog physical signature device
l
Determine the transformation TG that recovers 'x‘ from G(x) 206 ——->
E = TG(G(x))
V
Replace the appearance (‘0' or 'x', as applicable) in the individual
computer program with TG applied to the output of the analog 208 -——>
physical signature device associated with the execution of the
computer program upon being provided input 'x'
TG(PhySigG(x)) C E
210
Are there more program constants, variables, and/or function appearances to be replaced?
NO 212 ——>‘
l STOP
Figure 10
YES
US. Patent
Sep. 11, 2012
Sheet 11 0f 11
US RE43,658 E
Interactive
System\ Digital-to-Analog Conversion Means
Individual
Individual Computer
K10
Program Bound to
Analog Physical Signature Device
Individual Analog Signature Device 10
Analog-to-Digital Conversion Means
__.___________--1
Figure 11
US RE43,658 E 1
2
ANALOG PHYSICAL SIGNATURE DEVICES AND METHODS AND SYSTEMS FOR USING SUCH DEVICES TO SECURE THE USE OF COMPUTER RESOURCES
program is another example of identifying an individual com
puter resource by binding it to a uniquely identi?ed physical
object. In order to be reliable and unambiguous, the identi?cation of individual computer resources must be provided in a way
that cannot be subverted, modi?ed, sabotaged, tampered, Matter enclosed in heavy brackets [ ] appears in the original patent but forms no part of this reissue speci?ca
altered, cloned, copied, or in any other way, means or manner
undermined by parties seeking to violate the control of the
tion; matter printed in italics indicates the additions made by reissue.
computer resource. Examples of acts to be rendered as prac
tically impossible include, but are by no means limited to, removing the identi?cation of an individual computer resource (“anonymiZing”), changing the identi?cation of an
STATEMENT OF GOVERNMENTAL INTEREST
individual computer resource to the identity of a second com
This invention was made with Government support under
puter resource (“spoo?ng”), and creating a second computer
Contract No. FA8650-04-C-8002 awarded by the Department of the Air Force Small Business Innovative Research (SBIR) program. The Government has certain rights in the invention.
resource (“cloning”). Both of the examples of computer resource identi?cation
resource with the same identi?cation as an existing computer
through binding to a uniquely identi?ed physical object above, the serial number tag and the product identi?cation
FIELD OF THE INVENTION 20
This application is directed generally to computer resource security, and more speci?cally, to the binding of analo g physi cal signature devices to computer resources for the purpose of identifying and controlling the use of such bound computer
resources (“spoo?ng”), and duplicated (“cloning”). 25
These attacks and others mounted on the identi?cation of an individual computer resource through binding to a
30
uniquely identi?ed physical object are mounted on the uniquely identi?ed physical object as well as the binding of the uniquely identi?ed physical object to the individual com puter resource. Therefore, both the nature of the uniquely identi?ed physical object and the nature of its binding to the
resources.
BACKGROUND OF THE INVENTION
The security of computer resources has many diverse aspects. The facet of security of concern herein is controlling
sticker, are subject to all three of these attacks. Both the serial number tag and the product identi?cation sticker can be removed (“anonymiZing”), attached to alternative computer
individual computer resource must be considered when
the use of computer resources. By computer resources we
assessing the suitability and security of means for providing
shall mean throughout both computer hardware operated by means of program instructions (e. g., central processing unit,
through binding to an uniquely identi?ed physical object.
storage disc and peripheral device) and computer software that comprises said program instructions (e.g., executable
an individual computer resource with a unique identi?cation 35
computer program, linkable object library and programming
There are in the current art methods and systems for the identi?cation of an individual computer resource through
binding to a uniquely identi?ed physical object. In order to
language source code). A method and system to control the
counter attacks on the binding of the computer resource to the
use of a computer resource provides the means to describe,
uniquely identi?ed physical object in this case, means are provided such that the individual computer resource operates
implement and enforce policies regarding where, when, why,
40
correctly if and only if the binding to the uniquely identi?ed physical object is intact. A physical device employed as the uniquely identi?ed physical object in the identi?cation of an
how, and by whom the computer resource may be used. Controlling the use of computer resources provides ben e?ts to both the entity providing the computer resources and
the entity using the computer resources. The entity providing the computer resources can, for example, rely on methods and systems for controlling use of the computer resources to
individual computer resource is designated as a physical sig 45
computer resource implies the presence of the physical sig nature device and thus the physical signature device can be said to sign for and consequently authorize the use of the
insure that the computer resources are used in the proper
place, at the proper time, in the proper way and by the proper user. On the other hand, the entity using computer resources can, for example, rely on methods and systems for controlling
individual computer resource. 50
unambiguous
identi?cation
of
individual
and claimed in US. Pat. No. 4,599,489 (Solid state key for controlling access to computer software). Such a device is 55
computer
resources. For example, to implement the policy that a par ticular program must only be used on a particular computer, it is necessary to be able uniquely identify both the individual program and the individual computer.
often referred to as a “dongle”. An executable program soft ware computer resource that is bound to an individual dongle
will operate correctly if and only if it is currently connected to that individual dongle. In other words, the dongle is a physical
signature device. Physical signature devices are of two kinds: digital and 60
analog. The dongle is an example of a digital physical signa ture device. It stores a particular identi?cation number in
An individual computer resource can be provided with a
digital circuitry and provides this identi?cation number in
unique identi?cation by binding it to a uniquely identi?ed physical object. The metallic serial number tag on the back of a computer chassis is an example of identifying an individual
computer resource by binding it to a uniquely identi?ed physical object. The product identi?cation sticker on the jewel case or shrink-wrap containing an individual computer
A familiar and widely used example of binding a software computer resource to a physical signature device is described
use computer resources to insure that the computer resources
are ?t-for-purpose, are in working condition, are the latest versions and are genuine and unaltered. A necessary component of methods and systems for con trolling the use of computer resources is the reliable and
nature device because the successful use of the individual
65
digital form to the executable program on demand, typically through the serial, parallel or USB port on the computer on which the executable program is being used. When the executable program is placed into execution, the executable program checks for the presence of an individual dongle on
US RE43,658 E 3
4
the communication port and only continues to execute if the individual dongle is found to be present on the communica
resource and the uniquely identi?ed physical object used for its identi?cation. Another shortcoming of this method and
tion port. As another example of a digital physical signature device is
system is that the computer resource operates more slowly than it is capable of operating due to the necessity to continu ously decrypt the instructions and the data with and on which it operates and to continuously encrypt the results of applying the decrypted instructions to the decrypted data. Another shortcoming of this method and system is that is not readily
the trusted computing platform. An example of this technique is described and claimed in US. Pat. No. 6,327,652 (Loading
and identifying a digital rights management operating sys tem). When an executable program is placed into execution on an individual trusted computing platform, the executable
applied to computer resources other than executable program
program performs a cryptographic protocol to verify the
software computer resources.
authenticity of the credentials of the individual trusted com
A need exists, therefore, to provide a low-cost physical signature device and a method and system for binding said low-cost physical signature device to computer resources for
puting platform. If the credentials of authenticity not present or are not in order then the executable program does not
continue execution. A shortcoming of methods and systems based on digital
physical signature devices such as the dongle and the trusted
the purpose of controlling the use of computer resources that does not exhibit the above-mentioned shortcomings of the current art. Such a physical signature device should provide a
computing platform is that explicit instruction sequences
unique indicium (“signature”). Such as physical signature
must be included in and executed by the executable program
device shouldbe dif?cult to alter or duplicate. Such a physical
to interact with the digital physical signature device. These instruction sequences in the executable program, however, can be excised from or bypassed without affecting the func tionality of the computer resource. In this way, a version of the computer resource is created that can used successfully with
out requiring the presence of the digital physical signature device (“anonymiZing”).
signature device should be easily and yet tightly, securely and 20
signature device should be tamper-resistant and tamper-evi dent. Such a physical signature device should be able to be used with many different kinds of hardware and software
computer resources. The security provided by such a physical 25
Another shortcoming of methods and systems that use
digital physical signature devices such as the dongle and the trusted computing platform is that additional means must be provided to make it dif?cult to fabricate duplicate copies of
the digital physical signature devices (“cloning”) and to ensure that the unique identi?cation provided by the digital physical signature device cannot be altered (“spoo?ng”). Pro
irrevocably bound to a computer resource. Such a physical
signature device should not be based exclusively on instruc tions for the purpose of interacting with the device. Nor should such a physical signature device require the encryp
tion/ decryption of the operating instructions for the computer resource or the use of a special purpose central processing 30
unit. BRIEF SUMMARY OF THE INVENTION
viding these means adds expense to the production of both the
computer resource and the uniquely identi?ed physical object used for its identi?cation and control of its use.
An object of the present invention is providing a low-cost 35
nature, is dif?cult to duplicate, and is tamper-resistant and tamper-evident. An additional object of the present invention is providing a low-cost analog physical signature device and a method and system for binding such an analog physical
Another shortcoming of methods and systems that use
digital physical signature devices such as the dongle and the trusted computing platform is that few precautions are taken to prevent intrusive physical investigation and analysis
(“tamper-resistance”) and intrusive physical investigations
40
and analyses may be performed without leaving any indica
evidence”). signature device is based on encryption of the instructions for operating the computer resource and execution of the encrypted instructions inside a special-purpose processor that is operative to decrypt the instructions as they are used to operate the computer resource. An example of this technique
signature device to computer resources for the purpose of controlling the use of such computer resources. An additional
object of the present invention is providing a low-cost analog physical signature device and a method and system for bind
tions that an intrusion has been made or attempted (“tamper Another method and system available in the current art to control the use of a computer resource using a digital physical
analog physical signature device that provides a unique sig
ing such an analog physical signature device to computer 45
resources for the purpose of protecting against reverse engi
neering. These and other objects of the present invention are pro
vided by the relatively complex, immutable, inhomogeneous and unique properties of an individual physical object that is 50
bound to an individual computer resource for the purpose of
for an executable program software computer resource is
identifying and controlling the use of such individual com
described and claimed in US. Pat. No. 5,123,045 (Compre hensive software protection system). The executable program
puter resource. A physical object that has these properties and
and the data to which it is being applied are stored in an encrypted form in an uncontrolled computer memory. The uncontrolled computer memory is connected to a controlled
physical signature device.
central processing unit that is contained in a sealed, tamper resistant enclosure. The controlled central processing unit retrieves the encrypted instructions and data from the uncon trolled computer memory, decrypts the instructions and data once they are inside the controlled central processing unit, encrypts the results of applying the decrypted instructions to
is used for these purposes is referred to hereafter as an analog 55
the same time making it dif?cult to duplicate or alter the 60
analog physical signature device without altering or destroy ing such unique indicium. The aforementioned properties of an analog physical signature device also provide resistance to and evidence of attempts to intrusively examine, analyze or
alter the analog physical signature device.
the decrypted data, and places the encrypted results back in
Also in accordance with the present invention, the afore
the uncontrolled memory.
One shortcoming of this method and system is that it requires a special-purpose computer in a secure enclosure, which adds expense to the production of both the computer
The aforementioned properties of an analog physical sig nature device provide unique indicium (consequent, depen dent analog outputs that provide unique signatures) while at
65
mentioned properties of an analog physical signature device are embedded in and tightly bound to the functionality of the computer resource in such a manner that altering, tampering
US RE43,658 E 5
6
with or removing the bound analog physical signature device
Referring now to the drawings wherein like reference numerals or characters identify corresponding or similar ele ments throughout the several views, FIG. 1 is a schematic illustration of an analog physical signature device 10 accord
or its binding to the computer resource impacts the function ality of the computer resource to a degree that the computer resource is no longer of any use or value for its intended
Also in accordance with the present invention, the proper
ing to the present invention. The analog physical signature device 10 comprises a relatively complex, immutable (‘im
ties of embedding and tightly binding the analog physical
mutable’ is used in the sense that physical properties of the
purpose.
signature device to the computer resource provide protection
material are invariant over time unless the medium is subject
against reverse engineering of the computer resource.
to a deliberate externally-applied stimulus) inhomogeneous medium 11 that is con?gured and operative to generate, from
a predetermined analog input provided by an analog input
BRIEF DESCRIPTION OF THE DRAWINGS
means 12, a consequent and dependent analog output (the terminology “consequent, dependent” as hereinafter used to de?ne outputs means, that for any predetermined input, a ‘unique’ output is produced), detected by an analog detection means 14, that is unique to the individual analog physical signature device 10. In other words, the consequent, depen dent analog output of the analog physical signature device 10
A more complete understanding of the present invention and the attendant features and advantages thereof can be had
by reference to the following detailed description when con
sidered in conjunction with the accompanying drawings wherein: FIG. 1 is a schematic illustration of an analog physical
detected by analog detection means 14 represents and can
signature device according to the present invention. FIG. 2 illustrates an exemplary process for generating a
20
suitably function as the unique signature of the analog physi cal signature device 10 for the predetermined analog input provided by analog input means 12. This unique signature, in turn, reliably and securely authenticates and uniquely identi ?es the analog physical signature device 10 and, concomi
25
tantly, an individual computer resource to which it is bound.
unique signature using the analog physical signature device of the present invention and a predetermined light wave input. FIG. 3 illustrates an exemplary process for generating a
unique signature using the analog physical signature device of the present invention and a predetermined sonic wave
input.
An analog physical signature device 10 according to the present invention overcomes the shortcomings of prior art
FIG. 4 illustrates a translucent rod embodiment of the
digital physical signature devices in several respects.
analog physical signature device according to the present invention. FIG. 5 illustrates an imperfect mirror embodiment of the
First, the relatively complex, immutable, inhomogeneous 30
medium contained in or comprising an individual analog
analog physical signature device according to the present
physical signature device 10 has the property that it is, for
invention. FIG. 6 illustrates a solid block embodiment of the analog
practical purposes, impossible to reproduce with suf?cient precision to duplicate the signature produced by the indi
physical signature device according to the present invention.
vidual analog physical signature device 10 and as a conse
FIG. 7 illustrates the use of a program constant ‘c’ by a 35 quence, creation of a duplicate of (“cloning”) the individual
analog physical signature device 10 is, for all practical pur poses, statistically impossible. Second, the relatively complex consequent, dependent
computer program as known in the prior art.
FIG. 8 illustrates the steps implemented by a computer program in using a constant ‘c’ in a computation where a
Binding Transformation according to the present invention has been applied to the constant ‘c’ in the computer program. FIG. 9 illustrates the steps implemented by a computer program where a Binding Transformation according to the present invention had been applied to a program variable ‘x’ in the computer program. FIG. 10 illustrates one preferred exemplary method for replacing a program expression in a computer program using a Binding Transformation according to the present invention. FIG. 11 illustrates one preferred embodiment of a speci?c
40
purposes, impossible to alter in such a way that it is mistaken
for (“spoo?ng”) the consequent, dependent analog output generated by another analog physical signature device from 45
the same predetermined analog input. Thus, the innate complexity of both the relatively complex, immutable, inhomogeneous nature of the analog physical signature device 10, and the relatively complex nature of its
consequent, dependent analog output, provide protection against two well-known physical attacks, cloning and spoof
analog physical signature device for the execution method depicted in FIG. 10.
analog output produced by and which uniquely identi?es an individual analog physical signature device 10 is, for practical
50
ing, on systems and methods for controlling use of computer
resources using analog physical signature devices. Third, invasive attempts to physically analyze and explore the signature generation capability of the relatively complex, immutable, inhomogeneous medium of the analog physical
DETAILED DESCRIPTION OF THE INVENTION
Analog Physical Signature Device 55
signature device 10 will alter the consequent, dependent ana
An analog physical signature device by its intrinsic nature
log outputs produced by the relatively complex, immutable,
provides a wider range of signatures, is less expensive to
inhomogeneous medium, and thus will both destroy the capa bility of the analog physical signature device 10 to create its identifying signature and also make evident the invasion. Any interference with any consequent, dependent analog output in
construct, and is more dif?cult to attack than a digital physical
signature device. An analog physical signature device is inherently dif?cult to duplicate, clone or spoof because of its
relatively complex and inhomogeneous nature. An analog physical signature device is inherently tamper-resistant and tamper-evident because intrusive attempts to physically examine and analyze such an analog physical signature device irreversibly alters the device and thereby destroys the capability of the analog physical signature device to generate the unique signature ascribed to it.
60
an attempt to alter it to represent the analog output of another
analog physical signature device will destroy the identifying signature carried by such consequent, dependent analog out 65
put, likewise making evident the interference. As a result neither the analog physical signature device 10 nor the con
sequent, dependent analog outputs it produces require an additional or secondary protection system to protect their
US RE43,658 E 7
8
functional elements. Rather the inherent and indigenous nature of the analog physical signature device 10 and its
interface point B. The transformation of the predetermined input sonic wave to the consequent, dependent output sonic
consequent, dependent analog outputs simultaneously pro
wave by the relatively complex, immutable, inhomogeneous medium is the signature that uniquely identi?es the analog
vide and protect such functionality. Fourth, since the analog physical signature device 10
physical signature device 10. See FIG. 3 which illustrates an
exemplary process for using the analog physical signature
according to the present invention does not need to be built into the computer resource and since the analog input and
device 10 of the present invention to generate the unique
output interface requirements of any particular analog physi
signature of the analog physical signature device 10 by trans
cal signature device can be met using conventional, widely available analog input means 12 and analog detection means 14, the analog physical signature device 10 can be bound to a
forming a predetermined sonic wave input into a consequent, dependent sonic wave output.
For the ?rst class of embodiments of the analog physical signature device 10 according to the present invention, one
wide range of computer resources.
The analog physical signature device 10 according to the present invention creates a unique signature, i.e., consequent,
preferred embodiment of the analog physical signature
dependent analog output, for each predetermined analog
acrylic plastic, having embedded therein small re?ective
input, relying on the physical (“analog”) properties and pro
?akes 20 and/or small translucent colored glass balls 22, as exemplarily illustrated in FIG. 4, that functions as the rela
cesses inherent to the relatively complex, immutable, inho mogeneous material 1 1, rather than computational (“digital”) processes, to transform a particular input into a unique output. For the purposes of clarity and understanding, the follow
device 10 comprises a solid translucent rod 11, for example of
tively complex, immutable, inhomogeneous material, a 20
ing paragraphs describe two illustrative and exemplary embodiments of the analog physical signature device 10 hav ing utility in the practice of the present invention, one based
and a means 14 for detecting the consequent, dependent light wave output at the second know interface point B at the other end of the translucent rod 11.
on light waves and the other based on sonic waves. Those
skilled in the art will recognized that radiation from any part of an acoustic or electromagnetic spectrum could similarly be
25
employed, and accordingly, the invention of the present appli cation is not intended to be limited by such exemplary embodiments. For one class of embodiments of the analog physical sig nature device 10 according to the present invention, the par ticular physical process involves the transformation of a pre determined light wave input due to its interaction with, e. g., transmission through or re?ection/refraction from, the rela
tively complex, immutable, inhomogeneous medium of the analog physical signature device 10. A unique physical sig
means 12 for inputting a predetermined light wave at the ?rst known interface point A at one end of the translucent rod 11,
In another preferred embodiment of the analog physical signature device 10 using light waves, the relatively complex, immutable, inhomogeneous material of the analog physical signature device 10 comprises an imperfect mirror 11 made from glass with embedded impurities 26, e.g., air bubbles, and/or having surface irregularities 28, and/or an inhomoge
30
neous metallic backing 30, as exemplarily illustrated in FIG. 5. The predetermined light wave input is directed onto the imperfect mirror 10 at a ?rst known interface point A and the
consequent, dependent light wave output, i.e., unique signa ture, is detected at a second known interface point B. 35
In the foregoing embodiments of the analog physical sig nature device 10 according to the present invention using light
nature is created by interacting a predetermined light wave
waves, and in all others constructed and operated so as to
with the relatively complex, immutable, inhomogeneous
interact a predetermined light wave with a relatively complex, immutable, inhomogeneous medium 1, the nature of the
medium of the analog physical signature device 10 at a ?rst known interface point A and detecting the transformation of
40
transformation of the predetermined light wave input by the
this predetermined light wave produced by the relatively
relatively complex, immutable, inhomogeneous medium 11
complex, immutable, inhomogeneous medium at a second known interface point B. The transformation of the predeter mined input light wave to the consequent, dependent output
interface point B provides the consequent, dependent light wave output that uniquely identi?es the analog physical sig
light wave realized by the relatively complex, immutable, inhomogeneous medium is the signature that uniquely iden ti?es the analog physical signature device 10. See FIG. 2 which illustrates an exemplary process for using the analog
from the ?rst known interface point A to the second known
45
nature device 10, and, concomitantly, the computer resource to which the analog physical signature device 10 has been bound. For the second class of embodiments of the analog physical signature device 10 according to the present invention, one
50
preferred embodiment of the analog physical signature
physical signature device 10 of the present invention to gen
erate the unique signature of the analog physical signature device 10 by transforming a predetermined light wave input
device 10 comprises a solid block 11 of relatively complex,
into a consequent, dependent light wave output. For another class of embodiments of the analog physical
immutable, inhomogeneous material, a means 12 to direct a predetermined sonic wave at a ?rst known interface pointA in the volume of the block 11, and a means 14 to detect the consequent, dependent sonic wave output at a second known point B in the volume of the block 11 as exemplarily illus trated in FIG. 6.
signature device 10 according to the present invention, the particular physical process involves the transformation of a predetermined sonic wave due to its interaction with, e.g., transmission through or re?ection/refraction from, a rela
tively complex, immutable, inhomogeneous medium of the analog physical signature device 10. A unique physical sig nature, i.e., consequent, dependent analog output, is created
55
In another preferred embodiment of the analog physical signature device 10 using sonic waves, the relatively com 60
by interacting a predetermined sonic wave with the relatively
plex, immutable, inhomogeneous material 11 comprises a
complex, immutable, inhomogeneous medium comprising
closed hollow container ?lled with a viscous ?uid, a means 12 to direct a predetermined sonic wave at a ?rst known interface
the analog physical signature device 10 at a ?rst known inter face pointA and detection of the consequent, dependent out put sonic wave resulting from the transformation of the pre
point A in the volume of the ?uid, and a means 14 for detect ing the consequent, dependent sonic wave output at a second known interface point B in the volume of the viscous ?uid.
determined sonic wave produced by the relatively complex, immutable, inhomogeneous medium out at a second known
65
In yet another preferred embodiment of the analog physical signature device 10 using sonic waves, the relatively com
US RE43,658 E 9
10
plex, immutable, inhomogeneous material 11 comprises a
computer program, and thereby merges in an inseparable
disc of porous sintered metal, a means 12 to direct a prede termined sonic wave at a ?rst known interface point A of the porous sintered metal disc, and a means 14 to detect the consequent, dependent sonic wave output at a second known
manner the relatively complex, immutable, inhomogeneous and unique properties of the individual analog physical sig nature device and the functionality of the computer program. As a consequence of the method and system of the present
invention, the computer resource will function correctly if
interface point B of the porous sintered metal disc.
and only if it is operated in association with the analog physi
In yet another preferred embodiment of the analog physical
cal signature device to which it has been bound. Furthermore
signature device 10 using sonic waves, the relatively com
plex, immutable, inhomogeneous material 11 comprises
as a consequence of the method and system of the present
closed hollow container ?lled with ringing metal objects such
invention, to excise or bypass the computer instructions bound to the analog physical signature device would be tan tamount to excising or bypassing the functionality that the computer resource is intended to perform, essentially render ing the computer resource useless for its intended function
as tuning forks andbells, a means 12 to direct a predetermined sonic wave at a ?rst known interface point A in the volume of metal objects, and a means 14 to detect the consequent, dependent sonic wave output at a second known interface
ality.
point B in the volume of the metal objects. In yet a further preferred embodiment of the analog physi cal signature device 10 using sonic wave, the relatively com plex, immutable, inhomogeneous material 11 comprises a
Any useful computer program makes use of constant val ues. Constant values may be used in a computer program to
conditionally or unconditionally branch from one instruction
in the computer program to another instruction in the com membrane stretched over a rigid body or frame, a means 12 to direct a predetermined sonic wave at a ?rst known interface 20 puter program (a “logical” constant). Constant values may also be used as indexes and offsets into arrays of data (a point A on the stretched membrane 11, and a means 14 for
“pointer” constant). Constant values may also be used to
detecting the consequent, dependent sonic wave output at a second known interface point B on the membrane.
position text or graphics that are displayed to the user of the
program for the purpose of operating the program and indeed
In the foregoing embodiments of the analog physical sig nature device 10 according to the present invention using
25
sonic waves, and in all others constructed and operated so as
the text and graphics themselves may be represented by sequences of constant values (a “representational” constant).
to interact a predetermined sonic wave with a relatively com
Constant values may also be used as means to send messages
plex, immutable, inhomogeneous medium 11, the nature of the transformation of the predetermined sonic wave input by
to other computer programs (a “message” constant). Finally,
the relatively complex, immutable, inhomogeneous medium
in computer programs involving scienti?c calculations, con 30
stant values may be used in scienti?c formulae and math
1 1 from the ?rst known interface point A to the second known
ematical equations (a “computational” constant). Collec
interface point B provides a consequent, dependent sonic wave output that uniquely identi?es the analog physical sig
tively, any of the constant values of a useful computer program, as exemplarily illustrated by means of the foregoing
nature device 10, and, concomitantly, the computer resource to which the analog physical signature device 10 is bound.
examples, are de?ned herein as program constants. 35
Binding an Analog Physical Signature Device to a
Any useful computer program also makes use of variable values. Variable values may be used in a computer program to
hold input to the computer program (an “input” variable).
Computer Resource
Variable values may also be used in a computer program to
hold intermediate results (an “intermediate result” variable). The following paragraphs describe one preferred method for binding an analog physical signature device to a computer
40
Variable values may also be used in a computer program to
45
hold the memory address of data or instructions (a “pointer” variable). Variable values may also be used in a computer program to hold output from the computer program (an “out put” variable). Collectively, any of the variable values of a useful computer program, as exemplarily illustrated by
software resource to de?ne an interactive system that controls the use of such computer software resource for its intended purpose according to the present invention. In the case that the
computer software resource is operative to de?ne the func tionality of a computer hardware resourceisuch as software embedded in a disc or a printerithe method binds the analog
means of the foregoing examples, are de?ned herein as pro gram variables.
physical signature device to the computer hardware resource. In both cases the computer resource performs correctly if and
only if it is operated in association with the analog physical
50
signature device to which it has been bound. Thus we hence
forth speak without loss of generality of binding a computer program to an analog physical signature device without dif ferentiating between the cases that the computer program is a part of a computer hardware resource or is in the form of a
55
computer software resource. Thus, the terminology computer
Any useful computer program also makes use of functions of program constants and program variables. Functions of program constants and program variables may be used in a computer program to compute offsets into program data structures (an “offset” function). Functions of program con stants and program variables may also be used in a computer program to compute the size of program data structures (a “size” function). Functions of program constants and pro gram variables may also be used in a computer program to
software resource or computer program as used herein
compute positions in input or output formats (a “format”
embraces instructions that any digitally programmed device
function). Functions of program constants and program vari ables may also be used in a computer program to compute mathematical and scienti?c values (a “mathematical or sci enti?c” function). Collectively, any of the functions of pro
executes to realize a de?ned and predetermined functionality,
including but not limited to application programs, operating systems, basic input/output systems, and embedded program
60
instructions for hardware resources such as computer periph
gram constants and program variables of a useful computer
erals, industrial machines and consumer products. The binding of a computer program to an analog physical signature device according to the present invention embeds
program, as exemplarily illustrated by means of the foregoing examples, are de?ned herein as program functions.
the unique output from an individual analog physical signa
Such program constants, program variables, and/or pro gram functions, individually, collectively, and/ or in any com
ture device into the computer instructions comprising the
bination, are de?ned hereinafter using the terminology “pro
65
US RE43,658 E 11
12
gram expression”. During conventional execution of a computer program embodying any such program expres
ing a digital value to an analog signal and many means for
sions, these program expressions are processed by the instructions comprising the computer program as exemplar
causally relating an analog signal to a digital value. For example, digital-to-analog (D/A) converters are known prior
There are in the current art many means for causally relat
ily illustrated in the method of FIG. 7.
art devices or means that are operative to provide the causal
In a preferred embodiment of a method and interactive system according to the present invention, an individual ana
relationship function by converting digital values to an analog signal. Similarly, analog-to-digital (A/D) converters are
log physical signature device is bound to an individual com
known prior art devices or means that are operative to provide
puter program by replacing the code segment (the terminol
the causal relationship function by converting an analog sig
ogy ‘code segment’ as used herein encompasses both the
singular and plural) representing a selected program expres
nal to digital values. An example of an digital-to-analog con verter is described and claimed in US. Pat. No. 4,412,208
sion in the computer program with an alternative code seg ment that is a function of the unique output from the indi
digital converter is described and claimed in US. Pat. No.
(Digital to analog converter). An example of an analog-to
vidual analog physical signature device. The inventive
5,570,091 (Analog-to-digital converter). These types of D/A
consequence of such replacement is that the individual com
and A/ D conversion means have particular utility in the inter active systems described in Examples 3-5 below. Or, for example, a mapping function can be implemented
puter program will perform consistent with its intended pur pose if and only if it is operated in association with the individual analog physical signature device to which it has been bound. Another inventive consequence of this alteration is that the individual computer program is dif?cult to reverse
as the conversion means to de?ne the causal relationship 20
engineer.
each predetermined digital input ‘x’ to a predetermined ana
It is to be understood that a plurality of program expres sions in a computer program can be replaced with alternative
code segments to strengthen the binding of the computer program to the analog physical signature device. In such applications, each program expression is replaced by a spe
25
The mapping function would be further operative to causally
dence to such replaced program expression. 30
computer program in this interactive system is operative to transform a predetermined analog signal input to a conse
quent, dependent (unique) analog signal output. The bound computer program, including the alternative code segment
35
analog physical signature device, is only executable using
conversion means or software conversion means or a combi
digital values.
nation of hardware and software conversion means to realize 40
means that are operative to realize causal relationships
between digital values and analog signals to ensure the proper
functioning of both the computer program (using digital val
ues) and the analog physical signature device (using analog signals) to which it is bound. More speci?cally, the interactive system includes a digital-to-analog (D/A) conversion means 16 (see FIG. 11) that is operative to realize the causal rela
gx(t) to a prede?ned digital output ‘y’. The causal relation ships de?ned by such mapping functions may be arbitrary or may be associated with particular parameters of the analog signals. This type of D/A and A/D conversion means have particular utility in the interactive systems described in Examples 1-2 below. The digital-to-analog conversion means and analog-to digital conversion means used in embodiments of the method and interactive system of the present invention use hardware
embedded therein that binds the computer program to the
The interactive system, therefore, includes conversion
log input, fx(t). The predetermined analog input fx(t) is trans formed by interaction with the analog physical signature device into the consequent, dependent analog output gx(t). relate (by mapping) the consequent, dependent analog output
ci?c alternative code segment that has a singular correspon
Interactive System: The analog physical signature device that is bound to the
between digital values and analog signals. Such a mapping function would be operative to causally relate (by mapping)
45
such causal relationships. The realization of these means in the context of a speci?c embodiment of the method and
interactive system of the present invention depends on both technical and economic considerations of the computer resource whose use is being controlled and the analog physi
cal signature device being employed. For the purpose of the describing of method and interactive system of the present
tionship between a predetermined digital input, which is
invention, these conversion means need not be detailed
de?ned by the alternative code segment, and a predetermined
beyond being a transformation from the digital domain to the analog domain and a transformation from the analog domain to the digital domain, respectively, inasmuch as the selection
analog input for the bound analog physical signature device.
50
The interactive active system further includes an analog-to
digital (A/ D) conversion means 18 (see FIG. 11) that is opera
and implementation of such conversion means are within the capabilities of one skilled in the art.
tive to realize the causal relationship between the consequent,
dependent analog output produced by the analog physical signature device and a prede?ned digital output that is used in the program functionality of the bound computer program. Referring to FIG. 11, which depicts an interactive system according to the present invention, the conversion means 16, 18 can be implemented as elements of the analog physical signature device 10, as illustrated by the larger dashed rect angle. Alternatively, the conversion means 16, 18 can be
55
EXAMPLE 1
Binding Tabular Response to a Program Constant 60
By way of a simple explanatory example, assume we have a two different individual analog physical signature devices
implemented as elements separate and distinct from the ana
log physical signature device 10, as illustrated by the smaller
D:{dl, d2}. For the purposes ofthis simple example, assume
dashed rectangle. In these alternative embodiments, the con
each analog physical signature device (1, is a function from a set of integers X to a set of integersY, i.e., di: X—>Y in such a way that dl(x) #d2(x) for all x in X. Table 1 shows X and the mapping of both dl and d2 from X to Y.
version means 16, 18 can be implemented as stand-alone
hardware or implemented as part of the digitally-pro grammed hardware that holds the bound computer program.
65
US RE43,658 E 13
14
TABLE 1
output from the analog physical signature device. This PhyS ig(x) function, in addition to de?ning the predetermined digi
Two Analog Physical QiQnahlre Devices
tal input ‘x’ for the interactive system and method according to the present invention, also includes a mathematical formu
lation that is embedded in the bound computer program (see Table 3 below, column labeled TG) as well as instruction sets 8 9 10 11
19 21 18 12
for: (i) realizing the causal relationship between the predeter mined digital input ‘x’ and the predetermined analog input; (ii) realizing the causal relationship between the consequent, dependent analog output and the prede?ned digital output; (iii) retrieving the prede?ned digital output; and (iv) process
37 23 17 47
ing the embedded mathematical formulation using the pre de?ned digital input. Using the PhySig(x) function as de?ned herein, the binding of the computer program to the analog physical signature device dl can be expressed as:
In this case X:{7, 8, 9, 10, 11} andY:{6, 12, 17, 18, 19, 21,
23, 34, 37, 47}. Suppose the source code of the computer program to be
bound to devices from the collection of analog physical sig nature devices D, were the following:
READ I FROM FILE “Input”
READ I FROM FILE “Input”
IF (I>10) GO TO I IF (I>10) GO TO I
J:I+3
J:I+PhySig(8)—16 Example 1A 20 GO TO 2
Example 1C
GO TO 2 1 III—7
2 WRITE I TO FILE “Output” 25
2 WRITE I TO FILE “Output”
If this computer program is executed in association with
the analog physical signature device d1, then the program will
where the input I is assured to be an integer between 1 and 20. During the execution of this computer program, the con stant value ‘10’ in the second line is used to conditionally branch from one instruction in the program to another instruc
function correctly, as described above, for all values of I. If, on the other hand, this computer program is executed in 30
tion in the program depending upon the value of I read from
the ?le “Input”. For any value of the input I greater than the constant value, ‘ 10’, the program branches unconditionally to the statement labeled with the constant value ‘1’. This causes
the value of J to be set equal to the value of 1 minus the constant value ‘7’, which is written to the ?le “Output”. If the value of the input I is less than or equal to the constant value ‘ 10’, however, then the value of J is set equal to the value of I plus the constant value ‘3’ and the program branches uncon ditionally to the statement labeled with the constant value ‘2’, where the value of J is written to the ?le “Output”.
35
In the foregoing example, the predetermined digital input ‘8’ is de?ned by the PhySig(8) function of the analog physical signature device, and the expression “PhySig(8)—16” is the ‘alternative code segment’, which includes the embedded 40
gram. The prede?ned digital output for this particular example is ‘19’, the value of ‘y’ in Table 1 for the predeter
device d1, we replace one or more program constants in the
mined digital input ‘ 8 ’ . The functional procedure described in 45
the constant value ‘3’ in the third line (the computational constant) with the unique output from dl when x is 8. This transformation of the computer program of Example 1A
the preceding paragraphs wherein the code segment repre senting a program constant is replaced by an ‘altemative code
segment’ is exemplarin illustrated in FIG. 8. The binding of the computer program to analog physical signature device dl can be strengthened by replacing all con
yields the computer program in Example 1B: READ I FROM FILE “Input”
mathematical expression “y— 1 6” (see column TG in Table 3), that replaces the program constant “3” in the computer pro
By a preferred embodiment of the present invention, to bind this computer program to the analog physical signature
computer program with the unique output from the analog physical signature device d1. For example, we could replace
association with analog physical signature device d2, then this computer program will not function correctly for all values of I. In particular when I is less than or equal to the constant value 10, from the d2 column in Table 1 PhySig(8) will return 37, and I will be set to I plus PhySig(8)—16:21 and therefore, the computer program will not function correctly for values of I; 10.
50
IF (I>10) GO TO I
stant values in the computer program with calls to PhySig such that each call sends a different input value to the analog physical signature device. The result is as follows: READ I FROM FILE “Input”
J:I+dl(8)—16 IF (I>PhySig(7)+4) GO TO (PhySig(9)—20) GO TO 2
Example 1B 55
J:I+PhySig(8)—16 GO TO PhySig(11)—10
Example 1D
2 WRITE I TO FILE “Output”
Here we have d1 (8) equal to 19 from Table 1 and 19-16 is 3, which is the constant value necessary in the second line for the correct functioning of the program. Let PhySig(x) denote the interactive system and method
that de?nes the predetermined digital input ‘x’ that is causally related to the predetermined analog input to an analog physi cal signature device, which returns a prede?ned digital output that is causally related to the consequent, dependent analog
60
2 WRITE I TO FILE “Output”
In the example described above, a “binding” constant was added to or subtracted from the value returned by the analog 65
physical signature device function PhySig. For example, the binding constant 16 was subtracted from PhySig(8), the bind ing constant 4 was added to PhySig(7), to recover the corre
