U.S. patent application number 09/178606 was filed with the patent office on 2001-09-13 for system for controlling access and distribution of digital property.
Invention is credited to ABRAMS, MARSHAL D., SCHNECK, PAUL B..
Application Number | 20010021926 09/178606 |
Document ID | / |
Family ID | 24337542 |
Filed Date | 2001-09-13 |
United States Patent
Application |
20010021926 |
Kind Code |
A1 |
SCHNECK, PAUL B. ; et
al. |
September 13, 2001 |
SYSTEM FOR CONTROLLING ACCESS AND DISTRIBUTION OF DIGITAL
PROPERTY
Abstract
A method and device are provided for controlling access to data.
Portions of the data are protected and rules concerning access
rights to the data are determined. Access to the protected portions
of the data is prevented, other than in a non-useable form; and
users are provided access to the data only in accordance with the
rules as enforced by a mechanism protected by tamper detection. A
method is also provided for distributing data for subsequent
controlled use of those data. The method includes protecting
portions of the data; preventing access to the protected portions
of the data other than in a non-useable form; determining rules
concerning access rights to the data; protecting the rules; and
providing a package including: the protected portions of the data
and the protected rules. A user is provided controlled access to
the distributed data only in accordance with the rules as enforced
by a mechanism protected by tamper protection. A device is provided
for controlling access to data having protected data portions and
rules concerning access rights to the data. The device includes
means for storing the rules; and means for accessing the protected
data portions only in accordance with the rules, whereby user
access to the protected data portions is permitted only if the
rules indicate that the user is allowed to access the portions of
the data.
Inventors: |
SCHNECK, PAUL B.; (POTOMAC,
MD) ; ABRAMS, MARSHAL D.; (SILVER SPRING,
MD) |
Correspondence
Address: |
PILLSBURY MADISON AND SUTRO
INTELLECTUAL PROPERTY GROUP
1100 NEW YORK AVENUE N W
NINTH FLOOR EAST TOWER
WASHINGTON
DC
200053918
|
Family ID: |
24337542 |
Appl. No.: |
09/178606 |
Filed: |
October 26, 1998 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09178606 |
Oct 26, 1998 |
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08968887 |
Nov 5, 1997 |
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5933498 |
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08968887 |
Nov 5, 1997 |
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08584493 |
Jan 11, 1996 |
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Current U.S.
Class: |
705/54 ; 380/259;
380/287; 380/59; 713/182; 713/189; 713/193; 713/194; 726/2;
726/26 |
Current CPC
Class: |
G06F 2221/0724 20130101;
G06F 2211/007 20130101; G06F 2221/0742 20130101; G06F 2221/0797
20130101; G06F 21/577 20130101; G06F 21/62 20130101; G06F 21/86
20130101; G06F 2221/0704 20130101; G06F 21/6245 20130101; G06F
21/32 20130101; G06F 2221/0737 20130101; G06F 21/72 20130101; G06F
21/34 20130101; H04L 63/0428 20130101; G11B 20/00673 20130101; G06F
21/10 20130101; G06Q 30/018 20130101; G06F 2221/2143 20130101; G06F
2221/2145 20130101; H04L 9/0822 20130101; G06F 2221/2149 20130101;
H04L 2463/101 20130101; G06F 2221/2137 20130101; H04L 9/08
20130101; G06F 2221/2141 20130101; G06F 21/71 20130101; G06F
21/6209 20130101; H04L 2209/56 20130101 |
Class at
Publication: |
705/54 ; 380/259;
380/287; 380/59; 713/182; 713/189; 713/193; 713/194; 713/200 |
International
Class: |
H04L 009/00 |
Claims
What is claimed is:
1. A method of controlling access to data comprising the steps of:
protecting portions of the data; determining rules concerning
access rights to the data; preventing unauthorized access to the
protected portions of the data other than in a non-useable form;
and limiting each and every access to the data only in accordance
with the rules as enforced by a mechanism protected by tamper
detection.
2. A method of distributing data for subsequent controlled use of
the data by a user, the method comprising the steps of: protecting
portions of the data; preventing access to the protected portions
of the data other than in a non-useable form; determining rules
concerning access rights to the data; protecting the rules; and
providing the protected portions of the data and the protected
rules; whereby the user is provided controlled access to the data
only in accordance with the rules as enforced by a mechanism
protected by tamper detection.
3. A method of distributing data for subsequent controlled use of
the data by a user, some of said data having access rules already
associated therewith, the method comprising the steps of:
protecting portions of the data; preventing access to the protected
portions of the data other than in a non-useable form; determining
rules concerning access rights to the data; combining with said
determined rules any rules previously associated with the data;
protecting the combined rules; and providing the protected portions
of the data and the protected combined rules; whereby the user is
provided controlled access to the data only in accordance with the
combined rules as enforced by an access mechanism protected by
tamper detection.
4. A method of controlling secondary distribution of data, the
method comprising the steps of: protecting portions of the data;
preventing access to the protected portions of the data other than
in a non-useable form; determining rules concerning access rights
to the data; protecting the rules; providing the protected portions
of the data and the protected rules to a device having an access
mechanism protected by tamper detection; and limiting transmission
of the protected portions of the data from the device only as
protected data or in accordance with the rules as enforced by the
access mechanism.
5. A method of controlling access to data with a computer system
having an input/output (i/o) system for transferring data to and
from all i/o devices, said i/o system being specific to said
computer system, the method comprising the steps of: protecting
portions of the data; determining rules concerning access rights to
the data; preventing access to the protected portions of the data
other than in a non-useable form; and limiting each and every
access to the data only in accordance with the rules as enforced by
said i/o system.
6. A method of accessing data having protected data portions and
rules concerning access rights to the protected portions, the
method comprising the steps of: preventing access to the protected
portions other than in a non-useable form; and limiting each and
every access to the data only in accordance with the rules as
enforced by a mechanism protected by tamper detection.
7. A method as in any one of claims 1, 3, 4 and 5 wherein the step
of protecting portions of the data comprises the step of encrypting
the portions of the data, and wherein the step of preventing access
prevents access to the encrypted portions of the data other than in
encrypted form.
8. A method as in claim 7, wherein said step of encrypting encrypts
the portions of the data with a data encrypting key, said data
encrypting key having a corresponding data decrypting key, said
method further comprising the step of: encrypting the data
encrypting key.
9. A method as in claim 8, further comprising the step of:
providing a decrypting key corresponding to said key encrypting
key.
10. A method as in any one of claims 2 and 3, wherein the step of
protecting the rules comprises the step of encrypting the
rules.
11. A method as in claim 10, wherein the step of protecting
portions of the data comprises the step of encrypting the portions
of the data, and wherein the step of preventing access prevents
access to the encrypted portions of the data other than in
encrypted form.
12. A method as in claim 11, wherein the rules are protected such
that they can be viewed and they cannot be changed.
13. A method as in claim 11, wherein the step of encrypting the
rules comprises encrypting the rules with a rule encrypting key,
the step of encrypting the portions of the data comprises
encrypting the portions of the data with a data encrypting key, the
method further comprising the step of encrypting the data
encrypting key.
14. A method as in any one of claims 1, 2, 3, 4, 5 and 6, wherein
the data represent at least one of software, text, numbers,
graphics, audio, and video.
15. A method as in any one of claims 1, 2, 3, 4, 5 and 6, wherein
the rules indicate which users are allowed to access the protected
portions of the data, the method further comprising the step of
allowing the user access to a protected portion of the data only if
the rules indicate that the user is allowed to access that portion
of the data.
16. A method as in any one of claims 1, 2, 3, 4, 5 and 6 wherein
the rules indicate distribution rights of the data, the method
further comprising the step of: allowing distribution of the data
only in accordance with the distribution rights indicated in the
rules.
17. A method as in any one of claims 1, 2, 3, 4, 5 and 6, wherein
the rules indicate access control rights of the user, the method
further comprising the step of: allowing the user to access the
data only in accordance with the access control rights indicated in
the rules.
18. A method as in claim 17, wherein the access control rights
include at least one of: local display rights, printing rights,
copying rights, execution rights, transmission rights, and
modification rights.
19. A method as in any one of claims 1, 2, 3, 4, 5 and 6, wherein
the rules indicate access control quantities, the method further
comprising the step of: allowing access to the data only in
accordance with the access control quantities indicated in the
rules.
20. A method as in claim 19, wherein the access control quantities
include at least one of: a number of allowed read-accesses to the
data; an allowable size of a read-access to the data; an expiration
date of the data; an intensity of accesses to the data; an allowed
level of accuracy and fidelity; and an allowed resolution of access
to the data.
21. A method as in any one of claims 1, 2, 3, 4, 5 and 6, wherein
the rules indicate payment requirements, the method further
comprising the step of: allowing access to the data only if the
payment requirements indicated in the rules are satisfied.
22. A method as in any one of claims 1, 2, 3, 4 and 6, further
comprising the step of destroying data stored in the mechanism when
tampering is detected.
23. A method as in claim 5, further comprising the step of
destroying data stored in the i/o system when tampering is
detected.
24. A method as in any one of claims 2, 3 and 4, wherein the step
of providing provides the protected portions and the protected
rules together as a package.
25. A method as in any one of claims 2, 3 and 4, wherein the step
of providing provides the protected portions and the protected
rules separately.
26. A method as in any one of claims 2, 3 and 4, further comprising
the step of: providing unprotected portions of the data.
27. A method as in claim 24, further comprising the step of:
providing unprotected portions of the data in the package.
28. A method as in any one of claims 1, 2, 3, 4, 5 and 6, wherein
said rules relate to at least one of: characteristics of users;
characteristics of protected data; and environmental
characteristics.
29. A method as in claim 6, wherein the protected data portions are
encrypted and wherein the step of preventing access prevents access
to the encrypted portions of the data other than in encrypted
form.
30. A storage device, readable by a machine, tangibly embodying a
package of data comprising: protected portions of data; and rules
concerning access rights to the data, whereby a user is provided
controlled access to the data only in accordance with the rules as
enforced by a mechanism protected by tamper detection.
31. A device for controlling access to data, the data comprising
protected data portions and rules concerning access rights to the
data, the device comprising: storage means for storing the rules;
and means for accessing the protected data portions only in
accordance with the rules, whereby user access to the protected
data portions is permitted only if the rules indicate that the user
is allowed to access the portions of the data.
32. A device as in claim 31, further comprising: means for storing
data accessed by said means for accessing.
33. A device for displaying images represented by data comprising
protected data portions and rules concerning access rights to the
data, the device comprising: a tamper detecting mechanism; means
for storing the rules; means for accessing the data only in
accordance with the rules, whereby user access to the protected
data portions is permitted only if the rules indicate that the user
is allowed to access the portions of the data, said access being
enforced by said tamper detecting mechanism; and means for
displaying the images represented by the accessed data.
34. A device for outputting images represented by data comprising
protected data portions and rules concerning access rights to the
data, the device comprising: a tamper detecting mechanism; means
for storing the rules; means for accessing the data only in
accordance with the rules, whereby user access to the protected
data portions is permitted only if the rules indicate that the user
is allowed to access the portions of the data, said access being
enforced by said tamper detecting mechanism; and means for
outputting the images represented by the accessed data.
35. A device for outputting an audio signal represented by data
comprising protected data portions and rules concerning access
rights to the data, the device comprising: a tamper detecting
mechanism; means for storing the rules; means for accessing the
data only in accordance with the rules, whereby user access to the
protected data portions is permitted only if the rules indicate
that the user is allowed to access the portions of the data, said
access being enforced by said tamper detecting mechanism; and means
for outputting the audio signal represented by the accessed
data.
36. A device for outputting an output signal based on data
comprising protected data portions and rules concerning access
rights to the data, the device comprising: a tamper detecting
mechanism; means for storing the rules; means for accessing the
data only in accordance with the rules, whereby user access to the
protected data portions is permitted only if the rules indicate
that the user is allowed to access the portions of the data, said
access being enforced by said tamper detecting mechanism; and means
for outputting the output signal represented by the accessed
data.
37. A device for generating an output signal corresponding to data
comprising protected data portions and rules concerning access
rights to the digital data, the device comprising: a tamper
detecting mechanism; means for storing the rules; means for
accessing the digital data only in accordance with the rules,
whereby user access to the protected data portions is permitted
only if the rules indicate that the user is allowed to access the
portions of the data, said access being enforced by said tamper
detecting mechanism; and means for generating the output signal
from the accessed data.
38. A device as in claim 31, wherein the protected data portions
are encrypted using a data encrypting key and wherein the data
encrypting key is encrypted with a key encrypting key, the device
further comprising: means for obtaining a data decrypting key
corresponding to the data encrypting key using a key decrypting key
corresponding to the key encrypting key; means for storing the data
decrypting key; and wherein said means for accessing comprises:
means for decrypting the protected data portions using the data
decrypting key.
39. A device as in any one of claims 33 and 34, wherein said images
comprise at least one of text data, numbers, graphics data, and
video data.
40. A device as in claim 31, further comprising: tamper detecting
mechanism for detecting tampering with said device.
41. A device as in claim 38, further comprising: tamper detecting
mechanism for detecting tampering with said device.
42. A device as in claim 41, wherein said tamper detection means
comprises: means for destroying data including keys and other
cryptographic variables stored in the device when tampering is
detected.
43. A device as in any one of claims 33, 34, 35, 36, 37, 39 and 40,
wherein said tamper detecting mechanism comprises: means for
destroying data stored in the device when tampering is
detected.
44. A device as in any one of claims 36 and 37, wherein the output
signal comprises at least one of text, numbers, graphics, audio and
video.
45. A device for distributing data for subsequent controlled use of
the data by a user, the device comprising: means for protecting
portions of the data; means for preventing access to the protected
portions of the data other than in a non-useable form; means for
determining rules concerning access rights to the data; means for
protecting the rules; and means providing the protected portions of
the data and the protected rules; whereby a user is provided
controlled access to the data only in accordance with the rules as
enforced by an access mechanism protected by tamper protection.
46. A device for distributing data for subsequent controlled use of
the data by a user, some of said data having access rules already
associated therewith, the device comprising: means for protecting
portions of the data; means for preventing access to the protected
portions of the data other than in a non-useable form; means for
determining rules concerning access rights to the data; means for
combining with said determined rules any rules previously
associated with the data; means for protecting the combined rules;
and means for providing the protected portions of the data and the
protected combined rules; whereby the user is provided controlled
access to the data only in accordance with the combined rules as
enforced by an access mechanism protected by tamper detection.
47. A device as in any one of claims 45 and 46, wherein the means
for providing provides the protected portions and the protected
rules together as a package.
48. A device as in any one of claims 45 and 46, wherein the means
for providing provides the protected portions and the protected
rules separately.
49. A device as in any one of claims 45 and 46, wherein the means
for protecting portions of the data comprises means for encrypting
the portions of the data, and wherein the means for preventing
access prevents access to the encrypted portions of the data other
than in encrypted form.
50. A device as in any one of claims 45 and 46, wherein the means
for protecting the rules comprises means for encrypting the
rules.
51. A device as in claim 50, wherein the means for protecting
portions of the data comprises means for encrypting the portions of
the data, and wherein the means for preventing access prevents
access to the encrypted portions of the data other than in
encrypted form.
52. A device as in any one of claims 45 and 46, wherein the rules
are protected such that they can be viewed and they cannot be
changed.
53. A device as in claim 51, wherein the means for encrypting the
rules comprises means for encrypting the rules with a rule
encrypting key, the means for encrypting the portions of the data
comprises means for encrypting the portions of the data with a data
encrypting key, the device further comprising means for encrypting
the data encrypting key.
54. A device as in any one of claims 45 and 46, further comprising
means for providing unprotected portions of the data.
55. A device as in claim 47, further comprising: means for
providing unprotected portions of the data in the package.
56. A device as in any one of claims 45 and 46, further comprising:
means for detecting tampering with the access mechanism; and means
for destroying data stored in the access mechanism when tampering
is detected by the tamper detecting means.
57. A device as in any one of claims 30, 31, 33-37, 45 and 46,
wherein said rules relate to at least one of: characteristics of
users; characteristics of protected data; and environmental
characteristics.
58. A device as in any one of claims 30, 31, 33-37, 45 and 46,
wherein the data represent at least one of software, text, numbers,
graphics, audio, and video.
59. A device as in any one of claims 30, 31, 33-37, 45 and 46,
wherein the rules indicate access control rights of the user, the
device further comprising: means for allowing the user to access
the data only in accordance with the access control rights
indicated in the rules.
60. A device as in claim 59, wherein the access control rights
include at least one of: local display rights, printing rights,
copying rights, execution rights, transmission rights, and
modification rights.
61. A device as in any one of claims 30, 31, 33-37, 45 and 46,
wherein the rules indicate access control quantities, the device
further comprising: means allowing the user to access the data only
in accordance with the access control quantities indicated in the
rules.
62. A device as in claim 61, wherein the access control quantities
include at least one of: a number of allowed read-accesses to the
data; an allowable size of a read-access to the data; an expiration
date of the data; an intensity of accesses to the data; an allowed
level of accuracy and fidelity; and an allowed resolution of access
to the data.
63. A process control system comprising a device for controlling
access to data, the data comprising protected data portions and
rules concerning access rights to the data, the device comprising:
a tamper detecting mechanism; means for storing the rules; and
means for accessing the protected data portions only in accordance
with the rules, whereby output of protected data portions is
permitted only in such manner as is permitted by the rules, said
accessing being enforced by said tamper detecting mechanism.
64. A general purpose computer system comprising a device for
controlling access to data, the data comprising protected data
portions and rules concerning access rights to the data, the device
comprising: a tamper detecting mechanism; storage means for storing
the rules; and means for accessing the protected data portions only
in accordance with the rules, whereby user access to the protected
data portions is permitted only if the rules indicate that the user
is allowed to access the portions of the data, said access being
enforced by said tamper detecting mechanism.
65. A computer system as in claim 64, wherein said tamper detecting
mechanism comprises: means for destroying data, rules and
cryptographic variables stored in the device when tampering is
detected.
66. A computer system as in claim 64, wherein the protected data
portions are encrypted using a data encrypting key and wherein the
data encrypting key is encrypted with a key encrypting key, the
computer further comprising: means for obtaining a data decrypting
key corresponding to the data encrypting key using a key decrypting
key corresponding to the key encrypting key; means for storing the
data decrypting key; and wherein said means for accessing
comprises: means for decrypting the protected data portions using
the data decrypting key.
67. A computer system comprising: an input/output (i/o) system for
transferring data to and from all i/o devices, said i/o system
being specific to said computer system; means for protecting
portions of the data; means for determining rules concerning access
rights to the data; means for preventing access to the protected
portions of the data other than in a non-useable form; and means
for limiting each and every access to the data only in accordance
with the rules as enforced by said i/o system.
68. A system as in claim 67, further comprising means for
destroying data, including cryptographic variables, stored in the
i/o system when tampering is detected.
69. A system as in any one of claims 65 and 67, wherein the data
represent at least one of software, text, numbers, graphics, audio,
and video.
70. A system as in claim 67, wherein the means for protecting
portions of the data comprises means for encrypting the portions of
the data, and wherein the means for preventing access prevents
access to the encrypted portions of the data other than in
encrypted form.
71. A computer system as in claim 67, wherein the rules indicate
which users are allowed to access the protected portions of the
data, the system further comprising: means for allowing the user
access to a protected portion of the data only if the rules
indicate that the user is allowed to access that portion of the
data.
72. A computer system as in claim 67, wherein the rules indicate
distribution rights of the data, the system further comprising:
means for allowing the user to distribute the data only in
accordance with the distribution rights indicated in the rules.
73. A system as in claim 67, wherein the rules indicate access
control rights of the user, the system further comprising: means
for allowing the user to access the data only in accordance with
the access control rights indicated in the rules.
74. A system as in claim 73, wherein the access control rights
include at least one of: local display rights, printing rights,
copying rights, execution rights, transmission rights, and
modification rights.
75. A system as in claim 67, wherein the rules indicate access
control quantities, the system further comprising: means allowing
the user to access the data only in accordance with the access
control quantities indicated in the rules.
76. A system as in claim 75, wherein the access control quantities
include at least one of: a number of allowed read-accesses to the
data; an allowable size of a read-access to the data; an expiration
date of the data; an intensity of accesses to the data; an allowed
level of accuracy and fidelity; and an allowed resolution of access
to the data.
77. A system as in claim 70, wherein said means for encrypting
encrypts the portions of the data with a data encrypting key, said
data encrypting key having a corresponding data decrypting key,
said system further comprising: means for encrypting the data
encrypting key with a key encrypting key.
78. A system as in claim 77, further comprising: means for
providing a decrypting key corresponding to said key encrypting
key.
79. A system as in claim 75, wherein the rules indicate payment
requirements, the system further comprising: means for allowing the
user to access the data only if the payment requirements indicated
in the rules are satisfied.
80. A system as in any one of claims 63, 64, 66 and 67, wherein
said rules relate to at least one of: characteristics of users;
characteristics of protected data; and environmental
characteristics.
Description
1. FIELD OF THE INVENTION
[0001] This invention relates to the control of distribution and
access of digital property as well as to the payment therefor.
2. BACKGROUND OF THE INVENTION
[0002] The development and deployment of digital information
networks is accompanied by new concerns for the protection of
rights to data and information. The U.S. Congress Office of
Technology Assessment identified the following key developments
relevant to the area of this invention: there has been an overall
movement to distributed computing; boundaries between types of
information are blurring; the number and variety of service
providers has increased. Information Security and Privacy in
Networked Environments, Congress, Office of Technology Assessment,
OTA-TCT-606, Washington, DC: U.S. Government Printing Office,
September 1994.
[0003] Computer networks allow more interactivity; and, most
significantly, electronic information has opened new questions
about copyright, ownership, and responsibility for information.
Technology, business practice, and law are changing at different
rates, law arguably being the slowest.
[0004] Intellectual property, or information, is different from
real property. A major difference between intellectual property and
real property is that intellectual property can be embodied in
forms which can be copied from the owner while the owner still
retains the original. For example, a broadcast or performance of a
musical composition can be recorded (and copies made of the
recording) while the composer retains the original composition; a
photograph can be 5 reproduced while the owner retains the original
negative.
[0005] In the past, when information was stored in analog form, the
copying and redistribution of such information, while problematic,
did not account for as much economic loss as is possible today. The
storage of information in analog form uses a physical medium that
is made to have some characteristic vary in proportion with the
information to be stored. For instance, the groove on a vinyl
record captures the frequency and intensity (volume) of a sound by
the extent of its excursion. At each stage in the process of
playing a record: the stylus tracing the groove, generation of a
small voltage, amplification of the voltage, and reproduction of
the sound, small errors are introduced. Today's high fidelity
systems are very accurate, but they are not flawless.
[0006] Indeed, copying a vinyl record to a cassette tape results in
a small, but noticeable, reduction in sound quality. If multiple
generations of recording (e.g., cascaded recordings) were
undertaken, the resulting product would be noticeably inferior to
the original. Similarly, when multiple generations of photocopies
of an image are made, the quality of the resulting image is
typically poor, with many dark and light areas that were not
present in the original image.
[0007] It is the inevitable gradual degradation of quality that has
proven to be a practical disincentive to large scale copying of
analog information. Notwithstanding this observation, where the
potential profits are high, such copying is undertaken even though
the resulting product's quality is significantly below that of the
original. Videotape copies of movies represent a good example. Some
fraction of the marketplace is willing to accept a lower quality
product in exchange for a significantly lower price. The logistics
associated with making large numbers of copies (an inherently
serial process), including obtaining the raw materials (cassettes),
the reproduction equipment, and the distribution channels also have
served to limit illicit production. Finally, the quality of the
product as well as the markings on the package distinguish it from
the original and may also serve as a disincentive (for some) to
purchase an illicit copy.
[0008] Just as the invention of the printing press changed the way
in which society interacted with information on paper, the
technical advances in digital computers and communications in the
closing years of the twentieth century have a potential for high
impact on legal, moral, and business practice. The printing press
is often credited as an enabling mechanism for the Renaissance and
the Reformation in Europe. The advances in digital information
technology will similarly impact commerce and law. Digital
technology enables changing the representation of information
without changing the content. (Of course the content can be changed
too.)
[0009] The storage of information in digital form depends on the
ability to encode information in binary form to arbitrary precision
and to record that binary form in a physical medium that can take
on two distinct characteristics. Preserving the fidelity of
information recorded in binary (using media with two distinct and
easily-differentiated characteristics) is easily accomplished. For
instance, a compact disc stores information (each binary digit or
bit) as the presence or absence of a hole (depression or pit) that
reflects or does not reflect light. Compared to the analog
recording of phonograph records, the information stored in each
hole is unambiguously a binary digit, the value of which is either
zero or one. No other values are possible. A digital tape stores
each bit as a magnetic spot that is oriented either north/south or
south/north. Today's digital sound systems use sufficiently many
bits to capture sound levels beyond the ability of the human ear to
distinguish a difference and in so doing attain so-called "perfect"
fidelity.
[0010] A digital file can be copied with no loss of fidelity (as
the mechanism need only distinguish between two
easily-differentiated states). With straightforward and well-known
error-correction mechanisms, even inevitable flaws can be made so
improbable as to occur fewer than once in ten billion bits.
[0011] As a result of the ability to copy a file with no loss of
fidelity, it is now almost impossible to differentiate a digital
copy from the digital original. In a network environment recording
materials, reproduction equipment and distribution are not
impediments to copying. Consequently, in the digital domain the
threshold inhibiting the making of illicit copies is significantly
lowered. Evidence that this is the case is presented by the
Software Publishers Association and by the Business Software
Alliance, each of which indicates that billions of dollars of
software is pirated (in the sense of being illicitly copied) each
year. Additionally, print publishers hesitate to expand into the
network marketplace because they are unable to control (in the
sense of receiving compensation in return for rights) secondary
distribution of their products as well as incorporation of their
products into derivative products. Digitally stored information may
include binary data, computer software, text, graphics, audio, and
video. The uses of this information include news, entertainment,
education, and analysis. Information may be distributed in many
ways, including networks, magnetic media, CD-ROM, semiconductor
memory modules, and wireless broadcast.
[0012] Copying and distributing large volumes of digital
information over long distances is becoming easier and less costly.
Such changes in cost and convenience of necessity impact business
decisions concerning producing, distributing, promoting, and
marketing. The commercial relationship among information producers
(such as authors, performers, and artists), distributors (such as
publishers, promoters, and broadcasters), and consumers must change
in response to the technology.
[0013] The law concerning intellectual property is in ferment.
Major revisions in the laws regarding the protection of computer
programs have been suggested. A Manifesto Concerning the Legal
Protection of Computer Programs, Samuelson, P. R. et al., Columbia
Law Review, vol. 94, no. 8, pp. 2308-2431, December 1994. The
European Union is working on harmonizing protection of intellectual
property rights with respect to technology and differences in civil
and common law countries. Commission of the European Union, Jul.
19, 1995, Green Paper on Copyright and Neighboring Rights in the
Information Society, catalogue number CB-CO-95-421-EN-C, ISSN
0254-1475, ISBM 92-77-92580-9, Office for Official Publications of
the European Communities, L-2985 Luxembourg. In the United States,
the issue of protection of intellectual property rights is being
addressed in the context of the National Information
Infrastructure. The uncertainty of legal protection over time and
from country to country only serves to emphasize the importance of
and need for technical protection of intellectual property rights
in information and data.
[0014] The principal technology which has been used for protecting
intellectual property is cryptography. However, devising practical
retail systems for delivery of intellectual property from
distributor to consumer, as distinct from confidential transmission
in national security and business activities among trusted and
cleared personnel, has required innovation.
[0015] Executable software-based cryptography can ensure that data
are distributed only to authorized users. The information to be
protected is encrypted and transmitted to the authorized user(s).
Separately, a decryption key is provided only to authorized users.
The key is subsequently used to enable decryption of the
information so that it is available to the authorized user(s).
[0016] Other ways of controlling access to portions of data or
software have included the use of external devices or tokens
(dongles) needed in order to access the data or selected features
of a program. Possession of the token is made evident to the
computer system by physical attachment of the token to the
computer. A token is generally attached to a printer, game, or
network port where executable software can check on its presence
prior to authorizing access. Diskettes have also been used as
dongles; their presence in the diskette drive is checked by the
executing software. Because they must be actively interrogated,
dongles are generally used to limit access to program features and
not to limit access to information.
[0017] Of those prior art systems which make some use of
encryption, none protects the data after it has been decrypted.
Thus, secondary distribution and multiple uses are possible.
[0018] Further, in all of the prior art, access is all or nothing,
that is, once access is granted, it cannot be controlled in any
other ways. This makes it difficult to control copying, secondary
distribution, as well as to obtain payment for all uses.
[0019] Originator controlled data dissemination is desirable.
Several policies for control of dissemination of paper documents
are specified in Control of Dissemination of Intelligence
Information, Directive No. 1/7, Director of Central Intelligence,
May 4, 1981. This Originator-Controlled (ORCON) policy has
motivated development of computerized access controls. ORCON
requires the permission of the originator to distribute information
beyond the original receivers designated by the originator. The
Propagated Access Control (PAC) policy and the related Propagated
Access Control List (PACL) were proposed as one way of implementing
ORCON. "On the Need for a Third Form of Access Control," Graubart,
R., Proceedings of the 12th National Computer Security Conference,
pp. 296-303, 1989. Whenever an authorized subject reads an object
with an associated PACL, that PACL becomes associated with the
subject. Any new object created by the subject inherits the PACL.
PACLs are associated with both subjects and objects.
[0020] Owner-Retained Access Control (ORAC) (described in "Beyond
the Pale of MAC and DAC: Defining New Forms of Access Control,"
McCollum, C. J., et al. Proceedings of the Symposium on Research in
Security and Privacy, IEEE Computer Society Press, 1990) is similar
to PAC in propagating ACLs with non-discretionary enforcement. ORAC
goes further, retaining the autonomy of all originators associated
with a given object in making access decisions, while basing
mediation of requests on the intersection of the access rights that
have been granted. ORAC is motivated to implement several of the
DCID 1/7 policies in addition to ORCON, namely NO_CONTRACTOR,
NO_FOREIGN, and RELEASABLE_TO.
[0021] Originator-Controlled Access Control (ORGCON) (described in
"Generalized Framework for Access Control: Towards Prototyping the
ORGCON Policy," Abrams, M. D., et al. Proceedings of the 14th
National Computer Security Conference, October 1991) is a strong
form of identity-based access control--it explicitly defines
authority and delegation of authority, provides for accountability,
and has an explicit inheritance policy. In ORGCON, the distribution
list is indelibly attached to the object (i.e., the distribution
list cannot be disassociated from the object, even in the limited
cases where copying is permitted). ORGCON is a read, no-copy
policy. Its formal model (taught in "A Rule-Set Approach to Formal
Modeling of a Trusted Computer System," LaPadula, L. J., Computing
Systems Journal, Vol. 7, No. 1, pp. 113-167, Winter 1994)
distinguishes among device types in order to deal with the policy
that no storage copy of an object is permitted. Information may be
copied only to the display and printer, but not to any other device
types.
[0022] The Typed Access Matrix (TAM) Model (described in "The Typed
Access Matrix Model," Sandhu, R. S., Proceedings of the Symposium
on Research in Security and Privacy, IEEE Computer Society, pp.
122-136, 1992; and "Implementation Considerations for the Typed
Access Matrix Model in a Distributed Environment," Sandhu, R. S.,
and G. S. Suri, 1992, Proceedings of the 15th National Computer
Security Conference, pp. 221-235) incorporates strong typing into
the access matrix model to provide a flexible model that can
express a rich variety of security policies while addressing
propagation of access rights and the safety problem. The safety
problem is closely related to the fundamental flaw in Discretionary
Access Control (DAC) that malicious code can modify the protection
state. Types and rights are specified as part of the system
definition; they are not predetermined in TAM.
[0023] The prior art, including cryptographic processes, tokens,
dongles, so-called "uncopyable" media, various executable software
protection schemes, and executable software for printing that
places an identifier on all printed output in a fashion not
apparent to a human, fails to limit either secondary distribution
or distribution of derivative works.
[0024] This shortcoming is not a failure of mechanism, but rather
it is an architectural design omission. The problem of copying by
the authorized user is simply not addressed. In each case, once the
data are available to an authorized user, they are basically
unprotected and may be copied, modified, or transmitted at will.
Schemes that include identifiers on printed material, although they
may aid in identifying the source of copied material, do not
prevent secondary distribution.
[0025] Executable software-based cryptography can ensure that data
are distributed only to authorized users. However, once data are
received they may be freely manipulated and redistributed.
[0026] The information to be protected is encrypted and transmitted
to the authorized user(s). In some systems the encrypted
information is made freely available. Separately, a decryption key
is provided only to authorized users. The key is subsequently used
to enable decryption of the information so that it is available to
the authorized user(s). It is at this point that the information is
subject to manipulation and redistribution without further
limitation.
[0027] As mentioned above, a dongle or token can be used to
authorize access to executable software. However, once access has
been granted to information that information is subject to
manipulation and redistribution without further limitation.
Further, dongles have proven to be unpopular because of the need to
keep track of them and ensure that they are separately secured.
[0028] Uncopyable media, generally used either to control
distribution of information or to control usage of executable
software, are unpopular because of the user's inability to create a
backup copy. Further, most so-called uncopyable disks have fallen
victim to general-purpose duplication programs, rendering their
protection useless. Sometimes, as in early releases of Lotus 1-2-3,
an uncopyable disk was provided with the executable software
release and had to be inserted in a floppy-disk drive for the
executable software to function (operating as a disk dongle). Users
soon learned how to by-pass the executable software so that the
disk need not be present. Even where partially effective, the
uncopyable disk did not serve as a deterrent to capturing
information and redistributing it.
[0029] The degree of protection of data is typically made by the
data owners and/or distributors based on their security analysis.
It is common to perform security analysis in terms of risks,
threats, vulnerabilities, and countermeasures. An owner's estimate
of the probability that a particular threat will materialize is
crucial to selecting appropriate rules to protect property
rights.
[0030] Threat can be characterized as the intensity of attack on
the data, which can be described as low, medium, and high.
[0031] Low For a security function to be rated as "suitable for use
in a low threat environment," it shall be shown that the security
function provides protection against unintended or casual breach of
security by attackers possessing a low level of expertise,
opportunities, resources and motivation. However, such a security
function may be capable of being defeated by a knowledgeable
attacker.
[0032] Medium For a security function to be rated as "suitable for
use in a medium threat environment," it shall be shown that the
security function provides protection against attackers possessing
a moderate level of expertise, opportunities, resources and
motivation.
[0033] High For a security function to be rated as "suitable for
use in a high threat environment," it shall be shown that the
security function provides protection against attackers possessing
a high level of expertise, opportunity, resources and motivation. A
successful attack is judged as being beyond normal
practicality.
[0034] The following list covers some common anticipated threats to
data and processing systems.
[0035] Threat: Capture of Output Signal
[0036] No matter what method is used to protect a data file, the
data stored therein can be captured as a signal en route to an
output device. Capture of an analog output results in some
degradation of signal quality. But the market for bootleg copies of
videos, for example, appears to be insensitive to such quality if
the price is right. A captured digital signal suffers degradation
of quality only as a result of bit errors (i.e., if the data
capture was not completely accurate).
[0037] This threat is well known to the entertainment industry.
Various approaches to protection have been incorporated in set-top
boxes discussed in "Inside the Set-Top Box," Ciciora, W. S., IEEE
Spectrum, pp. 70-75, April 1995.
[0038] Threat: Digital Copying
[0039] Once data have been decrypted, the resulting cleartext must
be protected from unauthorized copying. Creating an unauthorized
local copy, or disseminating the data without authorization each
results in an original-quality copy without compensation to the
owner.
[0040] Threat: Deliberate Attack via Legacy (pre-existing) and
Customized Hardware
[0041] High-intensity attack by attackers possessing a high level
of expertise, opportunity, resources and motivation must be
considered. Attackers in this category might include foreign
governments and industrial espionage agents, teenage crackers, and
resellers of pirated intellectual property. One manifestation of
this threat is in uncontrolled hardware. The nominally protected
information would be available in the memory and could be accessed
via dual-ported memory or even by DMA (direct memory access) from a
peripheral.
[0042] A strong indication of the usefulness and desirability of
the present invention can be found in the legislation pending
before the U.S. Congress to make illegal the by-passing or avoiding
of copyright protection schemes. See S.1284, 104th Congress, 1st
sess. (1995).
[0043] It is desirable to have a system of distributing data
(intellectual property) that prevents copying, restricts
re-distribution of the data and provides controlled access to the
data.
SUMMARY OF THE INVENTION
[0044] This invention controls access to and use and distribution
of data.
[0045] For example, when the data are in the form of textual and
graphical information, this invention can control how much of the
information is displayed and in what form; or, when the data
represents a computer software program, this invention can control
how much of the software's functionality is available. Classified
data are similarly controlled.
[0046] In addition, this invention controls secondary distribution
and creation of derivative works. Prior art systems rely on
software for security. Without the tamper detection/reset mechanism
of this invention, software can be modified or data can be
intercepted rendering useless any attempts at control.
[0047] Degrees of protection utilized in the computer system
hardware (for example, tamperproof and tamper-detect features) and
the cryptographic tools will depend on the nature of the data to be
protected as well as the user environment.
[0048] In one preferred embodiment, this invention is a method of
controlling access to data by protecting portions of the data;
determining rules concerning access rights to the data; preventing
access to the protected portions of the data other than in a
non-useable form; and permitting a user access to the data only in
accordance with the rules as enforced by a tamper detecting
mechanism.
[0049] In another preferred embodiment, this invention is a device
for controlling access to digital data, the digital data comprising
protected data portions and rules concerning access rights to the
digital data. The device includes storage means for storing the
rules; and means for accessing the protected data portions only in
accordance with the rules, whereby user access to the protected
data portions is permitted only if the rules indicate that the user
is allowed to access the portions of the data.
[0050] In another aspect, this invention is a method of
distributing digital data for subsequent controlled use of the data
by a user. The method includes protecting portions of the digital
data; preventing access to the protected portions of the data other
than in a non-useable form; determining rules concerning access
rights to the data; protecting the rules; and providing the
protected portions of the digital data and the protected rules. The
user is provided controlled access to the data only in accordance
with the rules as enforced by a tamper detecting access
mechanism.
[0051] In another aspect, this invention is a storage device,
readable by a machine, tangibly embodying a package of digital data
comprising protected portions of digital data; and rules concerning
access rights to the digital data, whereby a user is provided
controlled access to the digital data only in accordance with the
rules as enforced by a tamper detecting access mechanism.
[0052] The data represent computer software, text, graphics, audio,
and video, alone or in combinations.
[0053] The protecting is done by encrypting the portions of the
data, and access is prevented to the encrypted portions of the data
other than in encrypted form.
[0054] In some embodiments the rules are provided with the data,
whereas in others the rules are provided separately. The rules can
specify various access rights and controls, including rights of
further distribution of the data.
[0055] In preferred embodiments, data are destroyed when tampering
is detected.
[0056] The device containing the mechanism of the present invention
can be a stand-alone device such as a facsimile machine, a
television, a VCR, a laser printer, a telephone, a laser disk
player, a computer system or the like.
[0057] As noted above, the rules, policies and protections of data
are typically made by the data owners and/or distributors based on
their security analysis of various threats. The various threats
listed above are dealt with by countermeasures in the present
invention.
[0058] Threat: Capture of Output Signal
[0059] Countermeasure: Encrypt or Scramble Output Signal
[0060] Protection of the output signal is accomplished with
encryption of a digital signal (as is done in the present
invention) and scrambling of an analog signal. This solution
requires installing decryption or unscrambling capability in the
output device, TV or monitor, along with appropriate
tamper-detection capability. Encryption or scrambling might be
effected using a public key associated with the output device
(although, to prevent so-called "spoofing," obtained from a
certification authority and not from the output device).
Alternatively, the output might be encrypted or scrambled using a
private key only available to the designated output device (again
ensured via some certification mechanism). The output signal is
decrypted or unscrambled by the output device using its private key
and is not available in plaintext form outside of the device's
protected enclosure.
[0061] Countermeasure: Protect Output Signal by Packaging
[0062] The output signal is protected by making it unavailable
outside the access mechanism. A sealed-unit computer with tamper
detection provides the necessary protection. Examples of the
acceptability of such packaging include lap-top computers and the
original Macintosh computer, as well as integrated televisions,
VCRs and video or audio laser disk players.
[0063] Threat: Digital Copying
[0064] Countermeasure: Secure Coprocessor
[0065] Selection of a secure coprocessor is indicated to implement
protection against unauthorized use when an operating system (OS)
is determined to be untrustworthy--that is, when the OS cannot
provide adequate resistance to the anticipated threat. When the OS
is untrustworthy, any measures implemented in the OS, or protected
by it, can be circumvented through the OS or by-passing it.
[0066] Countermeasure: Detection of Unsealing
[0067] The protection provided by a coprocessor could be
circumvented by tampering. The coprocessor is protected by tamper
detection that causes the rules, cryptographic data, and decrypted
protected data to be destroyed. Both passive and active means are
used to effect such destruction. Semiconductor memory is volatile
and does not retain data when power is removed. A long-life battery
provides energy sufficient to allow rewriting (zeroizing)
nonvolatile memory containing, for example, the private key.
Without the private key the system will be unable to decrypt any
protected data and it must be returned to an authorized service
facility for installation of a new private key.
[0068] Threat: Deliberate Attack via Legacy and Customized
Hardware
[0069] Countermeasure: Keep the Information on the Coprocessor
Board
[0070] Access may be controlled if the information leaves the
coprocessor board only for output purposes. Deciphered information
is retained in memory on the coprocessor board, not in main memory.
Program execution occurs in the coprocessor on the board (e.g,
operating in the same manner as did so-called "accelerator"
coprocessors that allowed a user to install an 80286 processor in
an 80186 system, allowing the user to shift all functions to or
from the faster coprocessor using a software command). Where
information must leave the coprocessor board, e.g., to be sent to
an output device, it may, depending on the associated rules, be
encrypted. To receive and process encrypted data, the output device
must have an access mechanism as well as public and private keys
and tamper detect capability. Because some output peripheral
devices do not have the capability of retransmission, the device
may be a subset of the full access mechanism associated with a
processor or computer system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0071] The above and other objects and advantages of the invention
will be apparent upon consideration of the following detailed
description, taken in conjunction with the accompanying drawings,
in which the reference characters refer to like parts throughout
and in which:
[0072] FIG. 1 is a schematic block diagram of an embodiment of a
digital data access and distribution system according to the
present invention;
[0073] FIGS. 2 and 3 show logical data structures used by the
system depicted in FIG. 1;
[0074] FIG. 4 is a flow chart of the authoring mechanism of the
embodiment of the present invention depicted in FIG. 1;
[0075] FIG. 5 is a schematic block diagram of another embodiment of
a digital data access and distribution system according to the
present invention;
[0076] FIG. 6 is a logical data structure used by the embodiment
depicted in FIG. 5;
[0077] FIG. 7 is a flow chart of the authoring mechanism of the
embodiment of the present invention depicted in FIG. 5;
[0078] FIGS. 8 and 9 show schematic block diagrams of embodiments
of the access mechanism according to the present invention;
[0079] FIGS. 10(a)-13 are flow charts of the data access using the
access mechanisms shown in FIGS. 8, 9 and 15;
[0080] FIG. 14 shows an embodiment of the invention which uses an
external user status determination mechanism;
[0081] FIG. 15 is a schematic block diagram of an embodiment of a
distribution system for derivative works according to the present
invention;
[0082] FIG. 16 is a flow chart of data access using the access
mechanism shown in FIG. 15;
[0083] FIGS. 17(a) and 17(b) show packetized data according to the
logical data structures shown in FIGS. 2 and 6;
[0084] FIGS. 18(a)-23(b) show various examples of data and their
packaging according to the present invention; and
[0085] FIG. 24 shows various implementation levels of a typical
computer system employing an access mechanism according to the
present invention.
DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EXEMPLARY
EMBODIMENTS
[0086] A schematic block diagram of a presently preferred exemplary
embodiment of a digital data access and distribution system 100
according to the present invention is depicted in FIG. 1. System
100 includes two main components: a data distributor 102 and a user
104. The data distributor 102 takes data 106 and produces packaged
data 108 which are provided to the user 104 via communication
channel 105, perhaps in return for some form of payment 110.
[0087] Corresponding to each of the distributor 102 and the user
104 are the system's authoring mechanism 112 and access mechanism
114, respectively. The authoring mechanism 112 of the distributor
102 takes the data 106 to be packaged and produces packaged data
108 which is provided to user 104 by a distribution mechanism 118.
The packaged data 108 may include access rules 116 in encrypted
form encoded therewith, or the access rules 116 may be provided to
the user 104 separately (as shown in the embodiment of FIG. 5).
[0088] The access mechanism 114 of the user 104 takes the packaged
data 108, either including an encrypted version of the access rules
116 or having the access rules provided separately, and enables the
user to access the data in various controlled ways, depending on
the access rules.
[0089] Data 106 provided to or generated by the distributor 102 can
be any combination of binary data representing, for
example,.computer software, text, graphics, audio, video and the
like, alone or in combinations. As described below (with respect to
the embodiment shown in FIGURE IS), in some embodiments data 106
can also include other packaged data produced by an authoring
mechanism according to this invention.
[0090] The difference between the embodiments of the distributors
102 and 190, shown in FIGS. 1 and 15, respectively, is that the
distributor 102 (FIG. 1) does not include an access mechanism 114.
Accordingly, distributor 102 deals only with newly created data
(that is, with non-derivative data). The embodiment shown in FIG.
15 (discussed below) includes the functionality of the embodiment
shown in FIG. 1, and can also deal with input of protected data
(previously packaged by a distributor). The embodiment of
distributor 102 shown in FIG. 1 can be implemented purely in
software (depending on the trust level of the employees of the
publisher), whereas the embodiment of distributor 190 shown in FIG.
15 requires some hardware implementation.
[0091] Data 106 can also be provided to the distributor in
non-digital form and converted to digital form by the distributor
in a known and suitable fashion. The content of the data 106 can
include, for example, news, entertainment, education, analysis and
the like, alone or in combinations.
[0092] Note, as used herein, computer software refers to any
software program used to control any computer processor. This
includes, but is in no way limited to, processors in stand-alone
computers; processors in video and audio devices such as
televisions, video recorders and the like; processors in output
devices such as printers, displays, facsimile machines and the
like; and processors in appliances, automobiles, telephones and the
like.
[0093] The data 106 are typically intellectual property subject to
control. In some cases, distributor 102 may receive some form of
payment 110 from the user 104 for accessing the data. This payment,
or some part thereof, may then be provided directly to the actual
owner (not shown) of the data 106. Further, the payment or part
thereof may be made before, during or after use of the data.
[0094] As noted above, the packaged data 108 may include an
encrypted version of the access rules 116, or these rules may be
provided to the user separately. The logical data structure for the
packaged data 108 is shown in FIG. 2 and includes an encrypted body
part 120, an unencrypted body part 122, encrypted rules 124 (if
provided with the packaged data), and encrypted ancillary
information 126. Encrypted rules 124 are an encrypted version of
access rules 116.
[0095] The actual format and layout of the data is dependent on the
type of data, their intended use, the manner in which they are to
be accessed and the granularity of control to be exercised on the
data. An encyclopedia, for example, would likely be organized
differently from a movie or a musical selection. Since the data can
be any combination of binary data, different parts of the packaged
data 108 may be structured differently, as appropriate.
Accordingly, encrypted body part 120 is potentially made up of
encrypted body elements, and similarly, unencrypted body part 122
is potentially made up of unencrypted body elements.
[0096] It is, however, envisaged that in presently preferred
embodiments the data will be structured such that some data parts
or elements have header information which enables the data to be
traversed or navigated according to whatever rules are to be
applied and in a manner appropriate for those data.
[0097] An example of the structure of rules 116 is shown in FIG. 3,
wherein the rules include various forms of validity checking and
identification information such as version number 127,
authentication data 128, license number 130, intellectual property
identifier 132, first and last valid generations of the product
134, 136. The rules 116 further include an encrypted data key 138
as well as the actual rules 140, 142, 144-146 to be applied when
access is made to the data by a user. The actual rules include, but
are not limited to, standard, extended and custom permissions 140,
142, 144-146, and co-requisite rules (permission lists) of source
data 145.
[0098] The function of each field in the rules shown in FIG. 3 is
given in TABLE I, below.
1 TABLE I Field Function Version number 127 Defines internal
configuration template Authentication (hash) 128 Validates
integrity of this data file. License number of these Used by
publisher to rules 130. identify owner. Intellectual property
Identifies the identifier 132. intellectual property product. First
valid generation of Defines extent of the product 134. validity of
the license. Last valid generation of Defines extent of the product
136. validity of the license. Encrypted data key 138. Key to access
the data. Standard permissions 140. List of basic access
permissions for data. Extended permissions 142. List of extended
access permissions for data. Custom permissions 144. Executable
code modules. Co-requisite rules Indicates which source
(permissions) for source data rules are needed. data 145.
Token/biometrics 146 Indicates the physical tokens and/or biometric
characteristics (if any) required for identification of each
authorized user. System IDs/Public keys Other systems to which 147
these rules may be redistributed.
[0099] A complete introduction and references to further reading
concerning cryptography and cryptographic techniques and mechanisms
are found in Abrams, M. D. and Podell, H. J., "Cryptography,"
Security-An Integrated Collection of Essays, Abrams, M. D. et al,
eds. IEEE Computer Society Press, 1995, which is hereby
incorporated herein by reference.
[0100] The Authoring Mechanism
[0101] As shown in FIG. 1, the authoring mechanism 112 of the
distributor 102 takes data 106 and produces packaged data 108 for
distribution. The process of producing the packaged data which
includes rules 116 is described with reference to FIGS. 1-4.
[0102] The authoring mechanism 112 incorporates existing source
data 106 into a packaged format for dissemination. As noted above,
data 106 can include but are not limited to combinations of
computer software, text, graphics, audio, video and the like. The
data 106 may be provided to the authoring mechanism 112 in various
proprietary data formats used in vendor software packages as well
as having lower level formats for graphics, tables, charts,
spreadsheets, text, still and motion pictures, audio and the
like.
[0103] Using the authoring mechanism 112, those elements of the
data 106 that are to be encrypted are selected, as are the
cryptographic algorithms and protocols to be employed, the payment
procedures for the use of the data, and other decisions governing
how the user 104 will be permitted to use the data. These decisions
are used in constructing the permission lists to be included in the
rules 116. Different classes of users can be defined, based, for
example, on age, fee paid, qualifications and the like.
[0104] The presently preferred embodiment employs asymmetric
encryption algorithms in the authoring and access mechanisms. The
keys for these algorithms are protected within the system and are
never exposed. The data-encrypting key, K.sub.D, is the same for
all copies of the data. K.sub.D is selected by the distributor 102
and may be different for each product (i.e., for each packaged data
108). The symmetric encryption algorithm used for encrypting the
data is associated with K.sub.D and may also be selected by the
distributor. K.sub.D is encrypted using a rule-encrypting key
K.sub.R. When the rules are distributed with the product (packaged
data 108), K.sub.R is the same for all products and all embodiments
of the system. When the rules are distributed separately from the
product, K.sub.R can be unique for each version of the system. The
rule-encrypting key K.sub.R is known only to (and protected within)
each receiving computer of each user.
[0105] With reference to FIG. 4 which shows a flow chart of a
version of the authoring mechanism of the 5 present invention in
which the rules are distributed with the packaged data 108, the
distributor 102 (acting as a representative of the owner of the
data 106) selects a data-encrypting algorithm (DEA) (step S400) and
data-encrypting key K.sub.D (step S402), and encrypts the
data-encrypting key K.sub.D using K.sub.R (step S404). The
encrypted data-encrypting key K.sub.D is then stored in the
encrypted ancillary information 126 of the packaged data 108 (in
step S406).
[0106] The algorithm selection (in step S400) is based on an
assessment of risk, the degree of protection desired as well as
other factors such as speed, reliability, exportability and the
like. As used herein, risk refers to the expected loss due to, or
impact of, anticipated threats in light of system vulnerabilities
and strength or determination of relevant threat agents.
Alternatively, risk can refer to the probability that a particular
threat will exploit a particular vulnerability of the system. An
analysis of risk, threats and vulnerability is provided below.
Examples of possible data-encryption algorithms include, but are
not limited to, DES, RSA, PGP and SKIPJACK. The system may use a
preferred encryption algorithm and may also provide a mechanism for
using algorithms provided with the data 106 by the owner of the
data.
[0107] The data-encrypting key K.sub.D may be generated in a
typical manner, suitable for the selected data-encrypting
algorithm. For data having lower value to its owner, or having
lower risk of loss, all distributions may rely on a single
data-encrypting key (or perhaps a small number of data-encrypting
keys). Another encryption method, uses a unique data-encrypting key
for each item of data to be distributed.
[0108] Having selected a data-encrypting algorithm and key,
K.sub.D, (S400-S402) and having encrypted and stored the key
(S404-S406), the distributor 102 proceeds to process the various
elements of the data 106. The data are processed at a granularity
dependent on the type of restrictions needed on their use and on
the form of the data themselves, that is, the form in which the
data have been provided. The distributor obtains (step S407) and
examines each part or element of the data (at the desired
granularity) and determines whether or not the element being
processed (the current element being examined) is in the body of
the data (step S408) (as opposed to being rules or ancillary
information). If the current element being examined is determined
to be in the body of the data, the distributor then decides whether
or not the current data element is to be protected (step S410),
that is, whether or not access to that element of the data is to be
controlled and the data element is to be encrypted.
[0109] If the current data element is not to be protected, it is
stored (step S412) in the unencrypted body part 122 of the packaged
data 108. Otherwise, if the current data element is to be
protected, it is encrypted using the data-encrypting key K.sub.D
(step S414) and then the encrypted current data element is stored
in the encrypted body part 120 of the packaged data 108 (step
S416), after which the next element is processed (starting at step
S407).
[0110] For example, if the data 106 are a textual article, the
abstract of the article might not be protected (encrypted) while
the rest of the article would be.
[0111] If the current data element is determined not to be in the
body of the data (step S408), the distributor then determines if
the current data element is access rules provided by the data owner
(step S418). If so, the rules are protected by encrypting them
using the rule-encrypting key K.sub.R (step S420) and the encrypted
rules are then stored in the encrypted rules part 124 of the
packaged data 108 (step S422).
[0112] If the current data element (being processed) is not access
rules, the distributor determines whether or not it is ancillary
information (step S424). This information includes such things as
the identification of the publisher and the like. If the current
data element is determined to be ancillary information, the
ancillary information is protected by encrypting it using the
data-encrypting key K.sub.D (step S426) and then the encrypted
ancillary information is stored in the encrypted ancillary
information part 126 of the packaged data 108 (step S428).
[0113] If the data are rules or ancillary information to be
encrypted, then, after appropriate processing, the next data
element is processed (step S407).
[0114] If the current data element is not a body part, access rules
or ancillary information, some form of error is assumed to have
occurred and is processed (step S430). After the error has been
processed, the mechanism can continue processing the next data
element (step S407) or terminate, depending on the
implementation.
[0115] The operation of the system 101 shown in FIG. 5 differs from
system 100 of FIG. 1 in that the rules 116 are distributed to users
104 separately from the packaged data 108. This is achieved with an
authoring mechanism 148 which takes as input data 106 and rules 116
and produces, separately, packaged data 150 and packaged rules 152.
The packaged data 150 without the rules has the form shown in FIG.
6, which is essentially the same as the structure shown in FIG. 2,
but without the encrypted rules 124.
[0116] Note that an hybrid system, wherein some rules are packaged
with the data and other rules are packaged separately is foreseen,
using a combination of the mechanisms shown in FIGS. 1 and 5. In
such a system, an operator selects which mode of operation to
employ.
[0117] FIG. 7 shows a flow chart of a version of the authoring
mechanism 148 of the present invention in which the rules 116 are
distributed by distributor 102 separately from the packaged data
10. Rules 116 and data 106 can be presented to the authoring
mechanism 148 in any order, or in an interleaved fashion. In fact,
the rules 116 need not all be provided together. The distributor
102 first selects a data-encrypting algorithm and a data encrypting
key, K.sub.D (step S700). Then the authoring mechanism 148
processes the data element-by-element (starting at step S702). As
in the case of the mechanism shown in FIG. 4, a data element is
assumed to be one of either a body part, ancillary information or
access rules.
[0118] First it is determined whether or not the current data
element is a body part (step S716). If it is determined (in step
S716) that the current data element is a body element, then it must
be determined (in step S718) whether or not the data are to be
protected. As in the case when the rules are distributed with the
packaged data 108, the decision as to whether or not to protect a
specific data element depends on the owner of the data and the
distribution policies as implemented in the rules.
[0119] If the data are to be protected (step S718), the data in the
current data element are encrypted using data-encrypting key
K.sub.D (step S720) and then the encrypted data are stored in the
packaged data 150 in the encrypted body part section 120 (step
S722). On the other hand, if the data in the current data element
are not to be protected, the data are stored in the unencrypted
body part section 122 of the packaged data 150 (in step S724). In
either case, after the data element is stored (steps S722 or S724),
the next data element is processed (starting at step S702).
[0120] If the current data element is determined not to be a body
element (step S716), then the mechanism checks to determine whether
or not the current data element is ancillary information (step
S726). If the current data element is determined to be ancillary
information, it is protected by encrypting it using data-encrypting
key K.sub.D (step S728) and then the encrypted current data element
is stored in the packaged data 150 in the encrypted ancillary
information section 126 (in step S730). Then the next data element
is processed, starting at step S702.
[0121] If the current data element is neither a body element (step
S716) nor ancillary information (step S726), then the it is
determined whether or not the current data element is access rules
(step S732). If so, the rules are to be distributed separately from
the packaged data 150, and are processed accordingly as
follows:
[0122] If this is the first time the access mechanism is processing
rules for this data set then a rule-encrypting key KR must be
determined. Accordingly, it is determined whether these are the
first rules being processed for this data set (step S734). If so,
obtain and validate the serial number, SN, of the system (steps
S736 and S738). Then calculate the rule-encrypting key K.sub.R as a
function of the validated serial number (K.sub.R=f(SN), for some
appropriate function f (step S740). Function f may, for example, be
an inquiry to a certification database or certification authority
to obtain the public key so as to ensure that the serial number is
authentic. Having determined the rule-encrypting key (step S740),
encrypt the data key K.sub.D with the calculated rule-encrypting
key K.sub.R (step 8742) and store the keys (step S744). Next,
encrypt the rules using the rule-encrypting key K.sub.R (step
S746). The encrypted rules and the encrypted data key K.sub.D are
stored as packaged rules 152 for subsequent distribution. The
rule-encrypting key K.sub.R may be stored or recalculated from the
serial number whenever needed.
[0123] If it is determined (in step S734) that the this is not the
first rules being processed for this data set, then the
rule-encrypting key K.sub.R has already been calculated (step S740)
and stored (step S744). In that case, the rules in the current data
element are encrypted using the rule-encrypting key K.sub.R (step
S742).
[0124] Once the rules in the current data element are processed,
processing continues with the next data element (step S702).
[0125] If the authoring mechanism 148 determines that the current
data element is not a body part (step S716), ancillary information
(step S726) or rules (step S732), then some form of error has
occurred and is processed (step S748). After an error has occurred,
the mechanism 148 can either cease processing (step S750) or, in
some embodiments, continue processing further data elements (step
S702).
[0126] The data 106 provided to the distributor 102 and the
packaged data 108 (or 150 and packaged rules 152, if provided
separately) provided to the user 104, may be provided and
distributed in various ways, including but not limited to, via
digital communications networks (for example, the Internet or the
projected National Information Infrastructure (NII)), magnetic
media (for example, tape or disk), CD-ROM, semiconductor memory
modules (for example, flash memory, PCMCIA RAM cards), and wireless
(for example, broadcast). The packaged data 108 may be provided to
a user as a single packaged entity or as a continuous stream of
data. For example, a user may obtain a CD-ROM having a movie stored
as packaged data thereon or the user may obtain the movie as a
continuous stream of broadcast data for one-time viewing.
[0127] Information (such as the packaged data 108 from the
distributor 102 to the user 104) can be transmitted openly, that
is, using mechanisms and media that are subject to access and
copying. In other words, communication channel 105 may be
insecure.
[0128] The Access Mechanism
[0129] The access mechanism 114 allows a user 104 to access the
data in packaged data 108 (or 150) according to the rules provided
with (or separately from, as packaged rules 152) the packaged data
and prevents the user or anyone else from accessing the data other
than as allowed by the rules. However, having granted a user
controlled access to data (according to the rules), it is necessary
to prevent the user or others from gaining unauthorized access to
the data. It is further necessary to prevent the data from being
further distributed without authorization.
[0130] The access mechanism 114 used by the user 104 to access data
is described with reference to FIG. 8 and includes a processing
unit 154, read-only memory (ROM) 156, volatile memory (RAM) 158,
I/O controller 165 and some form of energy source 166 such as, for
example, a battery. Access mechanism 114 may also include
electrically-alterable non-volatile memory 160, a hard disk 162, a
display 164, and special purpose components such as encryption
hardware 168.
[0131] The access mechanism 114 is also connected via insecure
channels 174 and 176 and I/O controller 165 to various controlled
display or output devices such as controlled printer 178 and
controlled display monitor 180. (Interaction with these controlled
devices is described in detail below.) Various other devices or
mechanisms can be connected to I/O controller 165, for example,
display 155, printer 157, network connection device 159, floppy
disk 161 and modem 163. These devices will only receive plaintext
from the I/O controller 165, and then only such as is allowed by
the rules. The network connection device 159 can receive either
plaintext or encrypted text for further distribution.
[0132] All components of the access mechanism 114 are packaged in
such a way as to exclude any unknown access by a user and to
discover any such attempt at user access to the components or their
contents. That is, the access mechanism 114 is packaged in a
tamper-detectable manner, and, once tampering is detected, the
access mechanism is disabled. The line 167 depicted in FIG. 8
defines a so-called security boundary for the components of the
access mechanism 114. Any components required for tamper detection
(tamper detect mechanism 169) are also included as part of the
access mechanism 114. Tamper detect mechanism 169 is connected in
some appropriate manner to processing unit 154, energy source 166,
and non-volatile memory 160.
[0133] This invention employs a combination of physical
self-protection measures coupled with means for detecting that the
self-protection has been circumvented or that an attempt to
circumvent the self-protection measures is being or has been made.
When such intrusion is detected, passive or active mechanisms can
be employed to destroy data. For example, the following can occur
(not necessarily in the order stated, and usually in parallel): the
access mechanism 114 is made inoperative, all cryptographic keys
within the mechanism, the private key and any other keys and data
are destroyed (zeroized), and power may be applied to clear
non-volatile memory 160 and then is removed, resulting in loss of
all data stored in volatile memory 158 so as to deny access to
decryption keys as well as to any cleartext in those memories. As
noted above, several operations can be accommodated or performed
simultaneously when tampering is detected. This can be done by
hardware circuits. Based on risk assessment and the availability of
particular technology, other implementations may be selected.
[0134] Tamper detection allows the access mechanism 114 to ensure
that all internal data (both the system's data and any user data)
are destroyed before any tamperer can obtain them.
[0135] One way to deny access to the data within access mechanism
114 is to package all of the components within a physical case
which defines the area which is excluded from user access. As an
example, a typical portable lap-top computer meets the requirement
of having all components within the same physical package or case.
Detection that the case has been opened is straightforward and well
known.
[0136] As an alternative embodiment of the access mechanism 114,
the components of the access mechanism 114 can be used as a
co-processor of another processor or computer. In this case, as
shown in FIG. 9, the access mechanism 114 communicates with the
other computer 170 via a communications channel 172. The
co-processor can be implemented as a circuit board and is designed
to be plugged into the bus 172 on the main board (that is, the
mother board or planar board) of the other computer 170. In that
case, the computer 170 will operate normally unless it needs to
access controlled data, at which time it will pass control to the
access mechanism 114.
[0137] The degrees of protection used in the access mechanism (for
example, tamper-detect features) and the cryptographic tools
employed will depend on the nature of the data to be protected as
well as the user environment.
[0138] Several techniques for physically secure coprocessor
packaging are described by Yee (Yee, B., Using Secure Coprocessors,
Carnegie Mellon University, School of Computer Science,
CMU-CS-94-149, 1994 (also available Defense Technical Information
Center as AD-A281 255)). In Yee, physical protection is described
as a tamper-detecting enclosure. The only authorized way through
the enclosure is through a coprocessor-controlled interface.
Attempts to violate physical protection in order to gain access to
the components of the coprocessor module will be detected and
appropriate action taken. For example, detection of attack results
in erasure of non-volatile memory before attackers can penetrate
far enough to disable the sensors or read memory contents.
[0139] Any known form of tamper protection and detection can be
used, as long as it functions to destroy the data as required.
[0140] Any data which are to be sent out of the security boundary
167 are under the control of the access mechanism 114. All I/O
requests and interrupts are handled by the access mechanism
114.
[0141] All communication between the components of the access
mechanism 114 and the enclosed hard disk 162 is encrypted.
Therefore, if the hard disk is removed from the mechanism, any data
stored thereon will be inaccessible without the appropriate keys.
The encryption of the data stored on the hard disk can use
cryptographic keys generated within the access mechanism and which
are never known outside of the mechanism. In this way, when
tampering is detected, the cryptographic keys will be lost.
[0142] In general, within the system, the data are encrypted on any
non-volatile storage devices so that they remain unavailable in the
case of tampering. Unencrypted data are only present within the
access mechanism 114 inside the security boundary 167 in components
where the data can be destroyed when tampering with the access
mechanism 114 is detected.
[0143] With reference to FIGS. 8 and 9, the access mechanism 114 is
also connected via insecure channels 174 and 176 and bus 177 to
various controlled or uncontrolled display or output devices such
as described above. This allows the system to communicate with
uncontrolled devices (so-called standard devices) as well as
networks, within the context of the rules/permission list.
(Interaction with these controlled devices is described in detail
below.) All communications on the insecure channels 174 and 176 and
on bus 177 is encrypted by the access mechanism 114 (and by the
authoring mechanism 112), and the controlled output devices 178 and
180 must have suitable processing capabilities within them
(including an access mechanism 114) to decrypt and process data
which they receive. The display or output devices used will depend
on the application and the type of data, and include, but are not
limited to, printers, video display monitors, audio output devices,
and the like.
[0144] The embodiment shown in FIG. 9 can also include other
standard devices (connected to bus 177) such as, for example,
standard printer 181, floppy disk 185, modem 187 and the like.
[0145] The Accessing Operation
[0146] When a user 104 obtains packaged data 108 (or 150) from a
distributor 102, the user can then access the data according to the
rules provided therewith or provided separately. Data access is
supported by the access mechanism 114 and is described with
reference to FIGS. 8, 9 and 10(a), where FIG. 10(a) is a flow chart
of the data access using the access mechanisms shown in FIGS. 8 and
9.
[0147] Note initially that, depending on the type of data to be
accessed and viewed, as well as the rules, the viewing process may
or may not be interactive. For example, if a user is accessing a
textual document, the user may choose to access only selected
portions of that document, the choice being made by viewing an
index of the document. On the other hand, if a user is accessing a
movie, the viewing may be continuous (if the rules do not allow a
user to re-watch portions of the movie without additional payment).
The access and viewing process is described here for an interactive
case, since non-interactive access can be considered access with a
single ("start-viewing") interaction.
[0148] Note further that initiation of the access mechanism
activates monitoring for interrupts and polling by the access
mechanism 114. A user may also implicitly invoke the access
mechanism by accessing an object (data) protected by the system.
This invocation also activates monitoring for interrupts and
polling.
[0149] The following discussion assumes, without loss of
generality, that the data are being accessed by an application via
an insecure operating system (OS) which invokes the access
mechanism 114. The intent is to show the manner in which controlled
access of the data takes place. In some foreseen environments, the
operating system will be little more than a simple run-time system
or there will be only one program running at all times. For
example, in a video cassette recorder and playback machine (VCR), a
single control program may be running at all times to control the
VCR's operations. In this case, this control program is considered
the application, and all access to controlled data is initiated by
the control program which invokes the access mechanism 114.
[0150] To initiate an input access to a data element, a user must
request the operating system to read such data into memory from an
I/O device. Initiating I/O gives control to the access mechanism
114.
[0151] For input access to an input data element, the access
mechanism 114 first determines whether the dataset containing the
data element is already open (step S1000). If the dataset is not
already open, it is opened (step S1001). Once opened, it is
determined whether or not the dataset is protected (step S1002).
Note that the data being accessed may or may not be part of
packaged data. In some embodiments the access mechanism 114 can
maintain a record of which open datasets are protected.
[0152] If it is determined that the dataset is not protected (step
S1002), then control returns to the invoking process (step S1006).
On the other hand, if the dataset is protected (step S1002) then it
is determined whether or not the rules for this dataset are useable
(present, available and valid) (step S1004). (The process of
determining whether the rules are useable, i.e., step S1004 is
described below with reference to FIG. 11.)
[0153] If the rules are determined to be useable (step S1004) then
it is determined whether the data element being accessed is
different from the most recently accessed data element (step
S1008). If so, the data element is opened (step S1010) (otherwise
the data element is already opened and available).
[0154] Next it is determined whether or not the data element is
protected (step S1012). If the data element is not protected then
control returns to the invoking process (step S1006). Otherwise, it
is determined whether or not access is permitted (according to the
rules) (step S1014). If no access to the data element is permitted
then an access denial operation is performed (step S1016). For
example, depending on the rules, the access mechanism 114 could
either return to the invoking process (e.g., the operating system)
or abort or perform some other operation. Following the access
denial operation (step S1016), control returns to the invoking
process (step S1006).
[0155] If access to the data element is permitted (step S1014),
then the data element is made available, consistent with the rules,
(step S1018) and control returns to the invoking process (step
S1006).
[0156] If, in step S1004, it is determined that the rules are not
useable, then an access denial operation is performed (step S1016),
following which control returns to the invoking process (step
S1006).
[0157] In some embodiments and/or uses of the system, the system
obtains and sets up for enforcement all of the rules in the
encrypted rules 124 prior to any data access or selection. In other
embodiments and/or uses, rules are set up or interrogated for
enforcement as needed. Depending on the type of the data and the
intended application, a minimal set of global rules (governing any
or all access to the data) is typically set up prior to any data
access. Accordingly, the enforcement of some of the rules is set up
when the package is obtained, prior-to any user access.
[0158] In some embodiments some of the required rules may not
actually be provided, but are indicated by reference. In those
cases, the referenced rules must be obtained when needed before
data processing can continue.
[0159] Once the appropriate rules, if any, are set up (stored
within the access mechanism 114), and the access mechanism is ready
to enforce them, then, according to the rules, the user can access
an element of the data.
[0160] The operating system is notified of the termination (normal
or otherwise) of each program so that it may close any files opened
by the program. Because it is possible that multiple programs may
be executing at the same time, the system will remain in a
protected state (if any protected data has been accessed) until all
active programs conclude their execution. At that time all
protected data in addressable memory are destroyed, and all
rules/permission lists of files that have been created are updated,
all files are closed and system status flags are reset.
[0161] Whenever a user wishes to access protected data, the access
mechanism 114 may determine that the rules are not yet available
for determination of whether or not to allow that access. Three
possibilities exist regarding the presence of the rules.
[0162] 1. The rules are packaged with the data.
[0163] 2. The rules are not packaged with the data but are already
present in the access mechanism 114 (i.e., in memory). This
situation occurs if, for example, the user loaded a disk containing
the rules and then the access mechanism 114, upon receiving the
interrupt announcing the disk's presence, read the first record,
recognized it as rules and decrypted them, storing them for later
use. (Reading a disk's contents in advance of any actual use is
presently done, for example, by some virus checking programs.) If
the implementor chose not to respond to interrupts when a device is
loaded, then, when rules are required, the access mechanism 114
checks all "ready" devices and inputs those rules that are present.
This covers the case where the rules are present on the hard
disk.
[0164] 3. The rules are not present. That is, the rules are not
packaged with the data and do not reside on any device attached to
the system. In this case, the access mechanism 114 notifies the
user that the rules are required. The user responds by either:
[0165] (a) indicating that the rules are not available (in which
case the access mechanism 114 denies permission to the program);
or
[0166] (b) loading the rules (in which case the access mechanism
114 confirms their identity and continues). If the access mechanism
is unable to confirm their identity, it can reissue a request for
the rules.
[0167] With reference to FIG. 11, first the access mechanism 114
checks to determine whether or not the rules are already determined
useable (step S1100). If so, the process returns a "success"
indication to the invoking process (step S1102).
[0168] If the rules have not already been determined to be useable
(step S1100), then the rules are located. First it is determined
whether or not the rules are packaged with the data (step S1104).
If so, the rules are made available (by decrypting them, if needed)
(step S1106). If the rules are successfully made available (e.g.,
decryption succeeds) (step S1108), then the rules are checked for
integrity (step S1110). If the rules pass an integrity check, then
a "success" indication is returned to the invoking process (step
S1112), otherwise a "fail" indication is returned (step S1127).
[0169] If the rules are not packaged with the data (step S1104),
then the access mechanism 114, determines whether the rules are on
a device attached to the access mechanism 114 (steps S1116-S1118).
If the rules are not found on any device, then the user is asked to
provide the rules (step S1114). At that time the user can abort the
process (step S1120), in which case a "fail" indication is returned
to the invoking process (step S1127). If the user chooses not to
abort but to provide rules, those rules are read (step S1122) and,
if they are a correct set of rules (step S1124), made available
(step S1106). If the rules are not a correct set of rules (step
S1124), then the user is informed (step S1126) and is prompted
again for the rules (step S1114).
[0170] Regardless of whether or not the rules are provided with the
packaged data, once the rules have been decrypted they are stored
in the access mechanism 114.
[0171] The process of executing an application to access the data
according to the stored rules is described with reference to the
flow chart shown in FIG. 12. For each data access operation to be
performed by the application, first the operation is identified
(step S1200) and the rules are checked (step S1202) to determine
whether that operation is permitted (step S1204).
[0172] If it is determined (step S1204) that the operation is not
permitted by the rules, a "failure" return-code is set (step S1206)
and control is returned to the caller (operating system) (step
S1208). On the other hand, if the operation is permitted (step
S1204) then, if payment is determined to be acceptable (step
S1210), then processing continues. (Payment is discussed further
below.) If payment is determined to be unacceptable (step S1210), a
"failure" return-code is set and control returns to the invoking
application (steps S1206 and 1208).
[0173] If payment is determined to be acceptable (step S1210), then
it is determined whether or not the rules apply any restrictions on
the data (step S1212) (for example, whether or not the rules
restrict the output format or amount of the data in some way). If
it is determined that the rules restrict the data then the
restriction is enforced (step S1214) and the I/O is performed based
on the restriction (step S1216), otherwise the I/O is performed
without restriction (step S1216).
[0174] After performing I/O (step S1216), a "successful" return
code is set (step S1218), and control returns to the invoking
application.
[0175] The Writing Operation
[0176] The process of writing data is described here with reference
to FIG. 10(b). When an application attempts to write to a dataset,
control is passed to the access mechanism 114 which opens the
dataset for writing if it is not already open (steps S1020, S1022).
Once opened, it is determined whether or not the dataset is to be
protected (step S1024). The dataset (output file) would be
protected if, for example, a protected dataset has been opened
since the last time the access mechanism 114 cleared its memory or
if the user indicated that output is to be protected (as when
authoring a work).
[0177] Note that an output dataset may begin as unprotected and be
written as unprotected (i.e., in the form it would have on a
machine which does not have an access mechanism 114) and later
additions to the dataset may require protection and therefore be
written in the appropriate format. The transition between
unprotected/protected data in a dataset are discussed below.
[0178] If the dataset is not to be protected (step S1024), control
returns to the invoking process which writes the unprotected data
(step S1026). On the other hand, if the dataset is to be protected
(step S1024, then the rules are checked to determine whether or not
output access is permitted (step S1028). If output access is not
permitted, a denial operation is performed (step S1030). For
example, depending on the rules, as part of this denial operation
the access mechanism 114 could destroy the output data allowing
randomized data to be written in their stead, could abort the
function, or could abort the job. If access is permitted (step
S1028), it is then determined whether a new data element is about
to be written or whether new rules have been incorporated since the
last write (step S1032). If either is the case, the rules are
written (step S1034). After writing the rules (step S1034), or if
neither was the case (step S1032), the data are encrypted if the
rules so require (step 81036), and control returns to the invoking
process (step S1026) where the (possibly encrypted) data are
written.
[0179] Compatibility Issues
[0180] A protected dataset (packaged data) read by a system which
does not employ an access mechanism 114 according to the present
invention (or a dataset read by a system in non-protected mode)
will be treated as data without any decryption taking place (by an
access mechanism). In such a system, protected data elements will
not be available to the user. This allows datasets (packaged data)
freely to be copied and transmitted. Recipients will need to obtain
any needed permission lists (rules) prior to being able to read the
encrypted data in such datasets.
[0181] A non-protected (e.g., legacy) dataset (read using a system
employing an access mechanism 114) that is treated as a protected
dataset would require that rules be present before it would be
accessed. The probability of such a mis-identification may be made
vanishingly small, e.g., by computing a hash function of the
data.
[0182] The user can be provided the opportunity to indicate that
the dataset should be treated as unprotected. In order to do this,
the access process described above with reference to FIGS. 10(a)
and 11 allows a user to override the decision made in step S1002 as
to whether or not the dataset is protected. Note that if a user
incorrectly indicates that a protected dataset is unprotected, no
access to the data would be available other than in encrypted
(unusable) form.
[0183] Tamper Detection
[0184] If and when tampering is detected, the access mechanism 114
performs at least the following operations illustrated in FIG. 13.
The cryptographic variables (e.g., keys) are destroyed (step
S1305), all rules are destroyed (step S1302), all cleartext
(un-encrypted) information is destroyed (step S1300), all files are
closed (step S1304), and the device is otherwise deactivated (step
S1306). While these operations are described sequentially, in
preferred embodiments they occur simultaneously or in some
concurrent or parallel order, as shown in FIG. 13. If some order
must be imposed on these operations, the first priority is to erase
the cryptographic variables (step S1305).
[0185] Operational Considerations
[0186] Certain operational procedures may also be important to
maintaining the protections and controls inherent in the present
invention. Specific operational procedures may be employed to
prevent equipment being built that would operate with an access
mechanism according to the present invention and that also
contained methods for circumventing the protections and controls in
the access mechanism.
[0187] These operational procedures involve inspection, analysis,
testing, and perhaps other procedures followed by certification of
authorized access mechanism implementations. The inspection might
include design analysis and physical chip inspection. Upon
successful inspection, a cryptographically sealed certificate is
stored within the protection perimeter. Note that this certificate
is one of the data items that is destroyed upon detection of
tampering. The certificate is issued by an authorized Certification
Authority (CA) and includes therein a decryption key issued by that
CA.
[0188] In some preferred embodiments, the rule-encrypting key
K.sub.R is encrypted using the encryption key corresponding to the
decryption key included in the certificate in each device. Then, in
order to obtain K.sub.R within the device, the device must have the
decryption key which was stored in the certificate by the CA.
[0189] Payment
[0190] In our market economy, producers and distributors of goods
and services expect to be compensated. Intellectual property
producers and distributors are no exception. The needs of commerce
have been a primary factor in the evolution of information
technology throughout history. Many of today's information
infrastructure activities also deal with billing and payment.
[0191] Existing payment mechanisms either assume that the parties
will at some time be in each other's physical presence or that
there will be a sufficient delay in the payment process for frauds,
overdrafts, and other undesirable conditions to be identified and
corrected. Many of these payment mechanisms have already begun to
adapt in response to the conduct of business over networks.
Entirely new forms of electronic payment are evolving.
[0192] The following is a representative (but not definitive) list
of electronic payment systems (some of the following names are
trademarks): Anonymous Internet Mercantile Protocol; "BITBUX" from
"MICROSOFT" and "VISA"; CARI (Collect All Relevant Information) the
Internet Voice Robot, uses virtual credit cards to provide secure
transactions from the Web; "CHECKFREE" plans for expanding the way
commerce is conducted on the Internet; "COMMERCENET" secure
commerce on the Internet based on Secure HTTP; "CYBERCASH";
"DIGICASH"; "DOWNTOWN ANYWHERE" has a system using account numbers,
and personal payment passwords; First Bank of Internet (FBOI);
First Virtual Internet Payment System allows real payment on the
Internet; IkP, A Family of Secure Payment Protocols from IBM;
Internet Banking White Paper from WebTech; NetBill Electronic
Commerce Project; "NetCash"; "NetCheque"; "NetChex"; "NetMarket";
"Netscape Communications Netsite Commerce Server" and "Netscape
Navigator"; "NexusBucks", "Open Market"; Security First Network
Bank is an Internet Savings Bank; SNPP: A Simple Network Payment
Protocol; Sun Internet Commerce Group; Virtual Bank of the
Internet.
[0193] Some electronic payment systems operate in real time by
communicating through the Internet or direct dial. Others employ a
prepaid balance which is debited against merchant credits, with
periodic batch updating and transmission.
[0194] It is envisioned that embodiments of the present invention
will employ an appropriate payment mechanism such as are well known
in the art. Accordingly, the actual payment mechanism is not
specified.
[0195] Rules and Policies
[0196] The rules (provided together with or separately from the
packaged data) embody the data owner's control policies with
respect to a user's access rights to the data.
[0197] The present invention permits the owner of intellectual
property to realize a gain by selling or licensing various levels
of access rights to the property and then ensuring that access
beyond those rights is not obtained. The present invention ensures
that only such qualities and quantities of access as released by
the owner (generally, in exchange for payment) are allowed.
[0198] The rules are preferably embodied in a permission list. An
example of permissions in such a list is shown in FIG. 3, and was
described above.
[0199] While the rules allowed are open ended, an example set of
rules (access control parameters) is given below. Access control
parameters may be combined to provide varying sets of capabilities
and to implement the enforcement of various policies. Some
parameters are independent of any other parameters; some parameters
are mutually exclusive; and other parameters must be used in
combination to define fully the actions to be allowed or
disallowed.
[0200] No Restriction
[0201] This would be the status if no restrictions were placed
on'the associated data. If this parameter is explicitly stated it
overrides any contradictory parameter that may also be present. The
data may be read, printed, executed, modified and copied.
[0202] No Modify
[0203] The associated data may not be edited or changed.
[0204] No Copy
[0205] The data may not be copied and a derivative work may not be
made from the data.
[0206] No Execute
[0207] The data may not be executed.
[0208] No Print
[0209] The data may not be printed.
[0210] Print With Restriction of Type n
[0211] If the user prints after accessing the data, a simulated
watermark will be printed as background or a header and/or footer
will be placed on each page. The numeral n specifies the specific
restriction to be applied, e.g., standard watermark (such as "do
not copy"), personal (watermark such as "printed for name of
user"), standard header/footer (such as "Company Name
Confidential"), or personal header footer (such as "Printed for
name of user").
[0212] No Access
[0213] Any user access, including an attempt to execute, will
retrieve only encrypted data (ciphertext). This is the default case
when there are no rules associated with data or the rules are
corrupted.
[0214] No Child Access
[0215] Unless the user has been identified as an adult (for example
by use of a password or a token) access will not be allowed for
items identified as "adult material."
[0216] Access Cost=(unit, price)
[0217] Each time a unit of data (e.g., book, volume, chapter, page,
paragraph, word, map, record, song, image, kilobyte, etc.) is
opened, a cost of price is incurred.
[0218] Print Cost=(unit, price)
[0219] Each time a unit (e.g., page, file, image, etc.) is printed,
a cost of price is incurred.
[0220] Copy/Transmit Cost=(unit, price)
[0221] Each time a unit (e.g., volume, file, record, page,
kilobyte, image, etc.) is output, a cost of price is incurred.
[0222] Execute only
[0223] The user may execute a program but may not read, print,
modify or copy it. This rule protects against disclosure of an
algorithm.
[0224] A permission list consists of rules governing the qualities
and quantities of access made available by the owner to a
particular user or group or class of users, and defines those ways
in which the user may (and may not) interact with the owner's
data/information. An encrypted permission list (for example,
encrypted rules 124 in FIG. 2) is made available by the owner to
the user, generally in exchange for fees (in the commercial domain)
(for example, payment 110 in FIG. 1). The system denies the user
direct access to manipulate the permission list, although in some
cases it may allow the user to view the permission list. (The
permission list may include rules governing access to the
permission list itself). Use of a permission list may be limited to
a particular computer system, a particular token (such as a smart
card), a user-supplied password, or any combination of these or
other items.
[0225] At the discretion of the intellectual property (data) owner,
a permission list may also be valid for future releases of the
data. This allows, for example, a software owner to plan for future
releases that resolve problems discovered in an initial software
release. In this example, the user of a particular version of a
program, for instance, Version 6, might be allowed to use a
subsequent version of the program, version 6.1, without further
payment and without needing to obtain a new permission list or
license. One who had not already licensed Program Version 6 would
be required to purchase a new permission list/license in order to
use Program Version 6.1.
[0226] A permission list may authorize and permit the user of
intellectual property to create a derivative product for which the
original owner may or may not have rights. In the case of a
derivative product for which the owner of the original intellectual
property has no rights, the owner of the derivative intellectual
property can unilaterally issue a permission list governing use of
that intellectual property.
[0227] Program execution occurs when a computer device follows a
series of steps, or instructions, expressed in some symbology. The
program may be linear, with one step always following its
predecessor without variation, or the program may involve branching
based on comparison of variables related to internal or external
events and status. In the field of computer science a distinction
is sometimes made according to the time at which the instructions
comprising the program are translated into the computer's machine
language in order to control the operation of the computer.
Accordingly, terms such as assembly, compilation, and
interpretation are used. This distinction is not important with
respect to the present invention. The term execution is used herein
to refer to all forms of program execution.
[0228] Controlling Primary Distribution
[0229] As noted above, digital information is transmitted openly.
Accordingly, the data are typically distributed in an encrypted
form.
[0230] Enforcing an Authorized User List
[0231] In some cases, it is useful to have a rule which controls
access to data for certain specific users or classes of users. For
example, data may only be accessible to people over the age of
eighteen, or to people having a rank greater than or equal to that
of captain, or to managers have a security clearance greater than
top-secret. In these cases, each user can be provided with a
separate set of rules for that specific user. In other words, each
user can be provided with a unique set of rules. However, if the
status of a user changes, then the rules for that user have to be
changed. Accordingly, it is useful and convenient to have the rules
be parameterized based on the status of the user and then have the
user's status provided to the access mechanism 114 in a secure
fashion.
[0232] The invention can be used in combination with software and
other identification technology (for example, biometric sensors) to
limit data access to users that possess an appropriate physical or
logical token (for example, a dongle or password), or personal
characteristic (for example, a fingerprint pattern). The secure
hardware (via tamper detection) eliminates the potential for
modifying and subverting the identification software.
[0233] An embodiment having such a configuration is shown in FIG.
14, wherein the access mechanism 114 is connected to an external
secure device 182 in order to obtain the user's status. Channel
183, connecting the secure device 182 and the access mechanism 114
is preferably a secure channel (within the security boundary 167),
however, if it is insecure, the device 182 must send information to
the access mechanism 114 in a protected (e.g., encrypted)
manner.
[0234] Controlling Access and Use
[0235] The invention can restrict the qualities or quantities of
access to data in any manner that can be calculated or enumerated.
A non-exhaustive, representative set of examples is given
below.
[0236] Access Control Qualities
[0237] (a) Local Display (for example, display of data on the
computer's monitor).
[0238] (b) Printing (i.e., fixation in a form intelligible to a
person).
[0239] (c) Copying (i.e., fixation on an electronic medium such as
a disk or tape).
[0240] (d) Transmission (see below regarding controlling secondary
distribution).
[0241] (e) Modification (i.e., changes to a copy of the primary
distribution).
[0242] Access Control Quantities
[0243] (a) Number of read-accesses (where "read access" refers to
any kind of examination or retrieval of data/information).
[0244] (b) Size of read-access.
[0245] (c) Expiration date.
[0246] (d) Intensity of access (number/total volume of
read-accesses in a unit of time).
[0247] (e) Resolution of access (for example, in the context of a
map this would be the maximum scale allowed; for sensor data this
would be the precision (number of bits) returned to the user).
[0248] (f) Delay (Accesses are permitted to data after a delay of n
time units. This allows different user groups to view the same
dataset with different results to queries. For example, a stock
broker would be able to view the latest data, while a customer,
paying less for the service, might receive data that are delayed by
15 minutes.)
[0249] Access Control Granularity
[0250] The above access control policies can be applied differently
to different portions of the intellectual property. For example, a
document's chapters might be controlled at different levels of
quantity and quality; a map's information might be controlled
differently at different latitudes and longitudes; portions of an
image may be restricted in availability, resolution, and the
like.
[0251] Controlling Secondary Distribution
[0252] The invention provides absolute control of secondary
distribution of data (for example, preventing or restricting
potential use).
[0253] Transmission of (an unencrypted copy of) the primary
distribution data (either to a network or to an output device such
as a tape or disk) can only be effected when the system, acting
under the rules embodied in the owner's permission list, allows
external output. Denial of permission to transmit an unencrypted
copy may result in no output or may result in transmission of an
encrypted copy (for which the recipient must then negotiate
permissions in order to use). Alternately, denial of permission to
transmit may result in the transmission of random data, thereby
denying the user knowledge of whether or not encrypted data was
transferred.
[0254] Since all storage of data on internal non-volatile memory
devices (for example, disks, flash memory, and the like) is
encrypted, this ensures that a physical attack on the system will
not result in compromise of plaintext.
[0255] Controlling Printing or Display
[0256] Printing or display of data is controlled in a manner
similar to that used for controlling secondary distribution. One
option is to disallow the ability to send particular information to
a printer or display. If printing or display is allowed, the data
stream to the output device is encrypted to ensure that an
unauthorized user cannot intercept data sent to an external printer
or display (that is, to a printer or display outside the
tamper-detect protected enclosure). This necessitates that the
receiving device contain a decryption subsystem. Thus, as shown in
FIG. 8, data from access mechanism 114 via I/O controller 165 to
either the controlled printer 178 or the controlled display 180 is
encrypted on channels 174 and 176, respectively.
[0257] As discussed above when addressing the threat of capture of
the output signal, an encryption mechanism is used for protecting
data transfers to printer or display so that, if the data owner
wishes, printing or display may be restricted to a specific printer
or display device.
[0258] Instead of disallowing printing or display, these functions
may be allowed with limitations as imposed by the owner. For
example, output might contain a header/footer on each page
indicating the identity of the authorized user; a watermark might
be printed in the background; or other identifying material might
be placed on each image. Of course, the data stream would be
encrypted (as above) to prevent interception.
[0259] Document marking and identification techniques can be used
to discourage the illicit copying of documents distributed in
either paper or electronic form. The exact form of printer
characters as well as line and word shifting have been used for
document marking and identification ("Document Marking and
Identification using both Line and Word Shifting," Low, S. H., et
al. 1995 INFOCOM Proceedings, IEEE, pp. 853-, 1995).
[0260] One of the major technical and economic challenges faced by
electronic publishing is that of preventing individuals from easily
copying and illegally or without authorization distributing
electronic documents. Cryptographic protocols used to discourage
the distribution of illicit electronic copies are described in
"Copyright Protection for Electronic Publishing over Computer
Networks," Choudhury, A. K., et al., IEEE Network, pp. 12-20,
May-June 1995.
[0261] Preferably, each controlled peripheral device (e.g.,
controlled printer 178 or display 180) is provided with an access
mechanism which allows the device to process data it receives. This
allows the data being sent to a controlled peripheral device from a
system using an access mechanism to be treated as either a copy of
data or a derivative work that is being sent to another user (that
happens to be a peripheral). In other words, if a peripheral device
contains an access mechanism, the data sent to the device can be
packaged data. Using this approach, requires that the receiving
access mechanism (the peripheral's access mechanism) may include
the rules (permission list(s)) in order to obtain the key needed to
decrypt the data in order to print or display them (or do whatever
the peripheral does with data). If no permission list is included
and the data are encrypted by the printer's public key, the
printer's access mechanism decrypts the data and prints them (just
as they would have been printed had the unencrypted data stream
been received by a standard printer).
[0262] The access mechanism in the controlled peripheral device
need not be a full system whenever the peripheral device is limited
in function, for example, to only printing or displaying data. The
peripheral and its access mechanism subsystem must be in a
tamper-detecting enclosure.
[0263] As noted, it is envisioned that a computer or other device
equipped with an access mechanism will be used with a controlled
output device (printer or display) so equipped. If the data owner
allows (via the rules) output (e.g., printing) to a controlled
output device (e.g., printer) (equipped with an access mechanism),
then there are two possibilities. The access mechanism in the
user's computer can process any required payment and send the data,
encrypted with the device's public key, to the printer or display
for output. Alternately, the access mechanism processes the data as
a derivative work (discussed below), packaging rules with the data,
and the output device is responsible for separate payment (for
example, allowing retention and multiple copies).
[0264] In order to limit the number of copies output, a short time
window is included in the rules so that the recipient cannot
capture (record) the file and replay it multiple times to the
output device. Additionally, the access mechanism in the output
device can contain a relatively small non-volatile memory that
would hold the checksum of a file that is not to be output again
for a certain time period, say, for 15 minutes from the first
output (and an output permission list in the rules would specify "n
copies, only valid for 15 minutes from x to x+15").
[0265] In the case of standard output devices (non-controlled,
i.e., without access mechanisms), data are provided unencrypted (to
the extent that the rules permit and payment has been
provided).
[0266] Controlling Distributions of Derivative Works
[0267] In many application environments where intellectual property
is created it is common to include extracts from other intellectual
property. Such environments include writing scholarly papers,
reviews, regulations, etc. The intellectual property containing the
extract is a so-called derivative work. The intellectual property
from which the extract was copied is called the parent work.
[0268] This invention controls the distribution of derivative works
(that is, works created using information owned by another).
Transmission of (an unencrypted copy of) a derivative work (to a
network, to an output device such as a tape or disk, or to a
printer or display device or the like) can only be effected when
the system, acting under the rules embodied in permission lists
created by each of the owners of any intellectual properties used
in the derivative work, allows external output. Denial of
permission to transmit an unencrypted copy may result in no output
or may result in transmission of an encrypted copy (or, as noted
above, may result in the transmission of random data). Use of an
encrypted copy of a derivative work will, in general, require
permissions from the owners of the derivative work as well as of
the original works. The permission list associated with a work is
incorporated into the permission list of any derivative work,
either directly or by reference. License fees and restrictions
imposed by the owner of a work are inherited by any derivative
works. An n-th generation derivative work inherits the license fees
and restrictions of each of its n-1 ancestors. If permission lists
(rules) are incorporated by reference, the access mechanism ensures
that the referenced permission lists (rules) are present (or it
will deny access).
[0269] For example, if printing of an original work requires a
watermark, then printing of any derivative work (if allowed at all)
will require a watermark. This monotonicity/cascading of
restrictions (i.e., each generation of a work must be at least as
restricted as the prior generation) ensures that a derivative work
that is only trivially changed from the original does not escape
restrictions imposed on the original.
[0270] Creation of a derivative work for subsequent distribution
requires an distributor 190 similar to distributor 102 shown in
FIGS. 1 and 5. However, derivative work distributor 190 (shown in
FIG. 15) includes an access mechanism 114 and can process, as input
data, packaged data 108a. The output produced by distributor 190 is
packaged data 108b which includes any rules (or references to
rules) required by data which is derived from the input packaged
data 108a. The access mechanism 114 within distributor 190
incorporates a global rule which enforces the distribution of rules
with derivative works.
[0271] As noted earlier, the difference between the embodiments of
the distributors 102 and 190, shown in FIGS. 1 and 15,
respectively, is that the distributor 102 shown in FIG. 1 does not
include an access mechanism 114. Accordingly, the distributor 102
deals only with newly created data (that is, with non-derivative
data). The embodiment shown in FIG. 15 includes that of FIG. 1, and
can also deal with input of protected data (previously packaged by
a distributor). The embodiment of the system shown in FIG. 1 can be
implemented purely in software, whereas the embodiment shown in
FIG. 15 requires some hardware implementation.
[0272] It is envisioned that a standard computer, equipped with an
access mechanism 114 will function as an authoring/distribution
system. This allows all computer users to become authors and to
incorporate previously published material into derivative
works.
[0273] The rules associated with the parent work determine whether
creation of derivative intellectual property is permitted, as well
as the inheritance rules for incorporating the rules of the parent
into the derivative work. Note that the rules derived from the
parent apply only to the extract and that these rules applying to
the extract need not be identical to the rules of the parent. The
rules applying to the extract are specified by the owner of the
parent, not by the creator of the derivative work.
[0274] For example, the rules applying to the extract might require
payment to the owner of the parent for use of the derivative work
containing the extract. If the creator of the derivative also
required payment, the user of the derivative would make payments to
two owners for use of the derivative. In an automated system the
details of such multiple payments would be invisible to a user.
[0275] This invention enables such payment arrangements that would
otherwise be prohibitively difficult and complex.
[0276] Another example relates to integrity and moral rights of the
owner of the parent. The owner might wish to ensure that an extract
was made without alteration or deletion, or that certain related
information were included (for example, to prevent the extract from
being taken out of context).
[0277] Data extracted from the parent comes with rules already
attached or associated. These rules propagate into the derivative,
but are applicable only to the extract. Extracts from the same
parent may or may not share rules. Extracts from multiple parents
may result in multiple rules applying to different extracts. As
noted, a derivative work may contain references to data and rules
rather than the actual data and rules. For certain commercial
products it may be desirable to have the final packaged data 108b
be fully self-contained. Accordingly, the packaged data 108b output
from this distributor 190 may require further processing in order
to optimize it for commercial distribution. Such optimization might
include, for example, obtaining and including copies of all rules
and data referenced in the package.
[0278] Extract Authentication
[0279] Digital signatures authenticate digital information by
providing proof that information received is precisely that which
was sent, with no changes. This system provides a similar
capability to authenticate extracts (quotes) of information.
[0280] Application environments, such as providing a legal trail of
evidence or authenticating that a quotation is accurate, are
enhanced by the ability to prove that the information has not been
subject to unauthorized alteration.
[0281] Authenticated extraction is implemented by creating an
extraction editor, that runs in the access mechanism 114. This
extraction editor, possibly under human direction, can extract
selected text but is unable to change the extract. When extraction
is complete, the access mechanism 114 digitally signs the extract
with a digital signature. This digital signature includes
identification of the specific computer in which the access
mechanism 114 is executing as well as identification of the
specific extraction editor used.
[0282] The extraction editor can, optionally, be permitted or
required to insert ellipsis to indicate deletions, and certain
specified insertions, such as, for example, "[sic]," might be
allowed.
[0283] In another embodiment, a so-called hyperlink can be used in
newly created data to indicate the insertion location of a
quotation. When an output operation is performed, the access
mechanism 114 creates a separate quotation, with its own checksum
and digital signature. Any recipient of data containing the
hyperlink can verify that the contents of the hyperlink were
captured by access mechanism 114 and delivered unchanged.
[0284] Controlling Use of Executable Software
[0285] Control of Primary Distributions
[0286] The invention enables the creator of executable software to
restrict the use of the software to only those who have acquired
permissions for various of its capabilities. Executable software
will be distributed in encrypted form, externally treated as data,
as described above. In general, execution of a program can be
controlled for multiple purposes in a number of ways. Purchase of a
license to execute software can be evidenced by a cryptographically
protected certificate which is decrypted internally by the access
mechanism 114. The executable software can check for the presence
of the certificate, or for permission keys or other information
contained in the certificate, once or many times during execution.
Since the algorithm embodied in an executable program may be
valuable intellectual property, the access mechanism 114 can
prevent a licensee from reading, copying, or modifying unencrypted
executable code. In order to prevent disclosure of the unencrypted
executable code, it is kept wholly within the security perimeter of
the access mechanism 114 for execution.
[0287] Elimination of the Distributor (Middleman)
[0288] The invention enables the executable software owner to make
copies easily available on a network server in encrypted form.
Users may download the executable software and then separately
purchase the rights to utilize the executable software. Thus, a
standard purchase of software may be accomplished electronically,
dealing with the owner's electronic commerce system. Thereby, the
entire process of acquiring the executable software package and
then purchasing the rights to use it may be effected without going
through a distributor.
[0289] Offering discounted upgrades to software licensees is also
simplified. When a licensee claims eligibility for a discounted
upgrade the executable software owner can check the record of
purchase of rights for the prior version of the product. Once
again, the entire process can be automated.
[0290] Simplification of Configuration Management
[0291] The executable software owner can elect to make available on
a network server product improvements that operate with existing
permission lists, thus immediately releasing product improvements
and fixes.
[0292] Multiple levels of product capability can be incorporated
into a single release and can be selectively enabled by different
permission lists. The tailoring of different distributions, with
differing capabilities is no longer necessary.
[0293] Active Control of Capability of Executable Software
[0294] The invention's control of distribution of data or
information (that are not executable software) may be characterized
as passive or transparent in that no changes are required in the
data or information for them to be protected. The permission list
that controls their use may be separately created, packaged, and
supplied.
[0295] The control of primary distribution of data or information
as well as the secondary distribution or distribution of
modifications (derivatives) of data or information is passive.
However, the invention's control of executable software capability
is active and requires that the executable software developer use
the programming interface provided by the system. At each point
where the developer requires authorization, the executable software
requests a permission-check. As a result, the process of FIG. 16 is
performed. If the requisite authorization is received, the function
of the software is performed. If authorization is denied, an
alternative action is chosen. The system may itself take certain
actions including, for example, terminating a program or erasing
data, when authorization is denied. As executable software is
distributed in encrypted form, it can only be decrypted and
executed (used) on a machine employing the access mechanism of the
present invention.
[0296] With reference to FIG. 16, first the operation is identified
(step S1600) and the rules are checked (step S1602). Next it is
determined whether the rules permit the operation (step S1604). If
the operation is not permitted (or it is permitted but payment is
not acceptable (step S1606)), then it is determined whether any
system action is required (step S1608). If no system action is
required, the return code for "not allowed" is set and control is
returned (step S1610), otherwise the system action is performed
(step S1612) after which the return code for "not allowed" is set
and control is returned (step S1610).
[0297] If the operation is permitted (step S1604) and payment is
acceptable (step S1606), then the return code for "allowed" is set
(step S1616).
[0298] The invention can be used to restrict the qualities or
quantities of executable software execution in any manner that can
be calculated or enumerated. Representative non-exhaustive examples
of restrictions are given below. These restrictions may combined in
any fashion.
[0299] Levels of Capability
[0300] Access to Specific Parts of Code or Features
[0301] Control of sizes or quantities that can be handled. For
example, files may be allowed up to a specific size; complexity or
accuracy of a solution may be limited, number of parameters or data
points may be restricted, etc.
[0302] Quantitative Modifiers of Levels of Capability
[0303] Control of expiration dates, time of use, number and
frequency of uses and permitted users. For example, rights to use
of a file of data (whatever it contains) may expire on a certain
date; access to certain data may be limited to certain times of
day, days of the week or specific dates; a user may only be allowed
to access certain data a specified number of times (or a specified
number of times per day); or access to some data may be restricted
based on the identity of the user.
[0304] Control of Secondary and Derivative Executable Software
Distributions
[0305] This is nandled in the same fashion as are data files, as
described above.
[0306] Control of Executable Software as a Module of Other
Executable Software
[0307] When protected executable software is incorporated into or
used by other executable software on the system for which it was
licensed, any limitations on its execution are maintained in the
new context.
[0308] Restricting Use to Certified Software
[0309] The access mechanism 114 can be factory configured to
restrict operation only to such software as is certified (e.g., by
using a digital signature to ensure that the software was received
unaltered from a certified source). Other contemplated applications
include key escrow (also called "data recovery") systems (described
below), systems for counting election ballots, systems for
exchanging cryptographic data or algorithms, and systems for
safeguarding financial, medical, or other personal data. Further, a
system employing an access mechanism may be used to ensure that
such software is not modified after being received or accessed for
execution.
[0310] Process Control
[0311] Computer control of processes, is the basis for automation
and quality control in many industries. This technology extends
into various specialties such as computer-aided manufacturing,
control systems engineering, concurrent engineering, expert
systems, intelligent sensors, just-in-time manufacturing,
programmable logic controllers, robotics, robotic programming
languages, and visualization techniques in engineering.
[0312] Formula, processes, procedures, and techniques may convey
product differentiation, aesthetic and functional innovation, and
increased cost-effectiveness. The computer programs and data
involved in process control may constitute valuable intellectual
property. The mechanisms of the present invention permit such data
to be stored in process-control computers, transmitted to suppliers
and subcontractors and otherwise employed without unauthorized
disclosure, substitution, or modification.
[0313] The permissions associated with process control data may,
for example, allow execution only--reading or observing the data
would be prohibited. Execution may be restricted to specific
equipment and to specific times. In general, the process controller
is external to the equipment implementing the process. Hence,
communication between the process controller and the process
equipment must be cryptographically protected. Like the access
mechanism in a controlled computer peripheral discussed herein, the
access function in the process equipment need not be a full system
whenever the peripheral device is limited and can not output
data.
[0314] Key Escrow (Data Recovery) Systems
[0315] This system allows a provider of key escrow cryptographic
executable software to require, by using a rule, certification that
a key has been installed and deposited with a specified
certification authority in order for the executable software to
function. The access mechanism ensures the integrity of executable
software that uses cryptographic executable software (whether or
not key escrow), guarding against change or replacement.
[0316] Control of Classified Data
[0317] The invention can be used to support limitations on the
(primary and secondary) distribution of data, access to data, and
distribution of derivative data where the data are classified.
Similarly, the execution of classified programs, or programs
operating on classified data may be controlled by the system.
[0318] Ensured Issuance of Receipts
[0319] This system can be used to ensure that a receipt is issued
under a number of circumstances, as demonstrated by representative
examples given below. A software program (or electronic mail
message) may request that a receipt be issued whenever it is loaded
or executed (or when a mail message is received); a receipt may be
issued when a mail message is read for the first time; or a program
will not be loaded or executed (or mail opened for reading) unless
the user first agrees to allow a receipt to be issued.
[0320] Ensuring Privacy
[0321] This system can be used to ensure privacy of sensitive
records in a database. Examples include financial, census, medical,
and political databases and the like. The system can allow
inquiries that provide statistical summaries but do not reveal
information about individuals. The rules would be used to limit the
queries that might be posed.
[0322] Owner Control/Privileges
[0323] At the time of purchase the identity of the owner may be
stored within the access mechanism. The access mechanism may allow
the owner to place a global set of rules (a global permission list)
in the mechanism. These global rules could control, for example,
hours of access (e.g., when the computer might be operated) based
on a clock within the access mechanism or an external time
reference with which the access mechanism communicates; acceptable
software which can be run using the access mechanism (i.e., a list
of those software products that would be allowed to be used, thus
enforcing a system administrator's configuration control rules);
user and-password lists, and the like. A user can thereby customize
a particular access mechanism.
[0324] The rules may also include or specify certain programs to be
run under certain conditions. For example, if the rules specify
that all printed output must contain a watermark, the rules might
also provide the watermark generating program. In these cases, the
programs are either pre-loaded into the access mechanism 114, or
are loaded when needed. These programs will then be executed when
the corresponding rules or functions are invoked. For example,
various types of watermark programs can reside in the access
mechanism 114, and, depending on the rules, the appropriate one of
these can be selected and executed.
[0325] Note that the data structures in FIGS. 2 and 6 depict
logical organizations of the data. However, the actual physical
format of the data depends on the type of the data as well as on
the manner in which the data are to be used. Further, as noted
above, the data package may be distributed in many ways, including
networks, magnetic media, CD-ROM, semiconductor memory modules, and
wireless broadcast and the like. In certain types of data
distribution, e.g., continuous cable or wireless broadcast, a user
may wish to begin accessing the data at an arbitrary point during
its distribution. For example, if the data represent a broadcast
movie which begins at 8 p.m., a particular user may only begin
viewing at 8:30 p.m. In this case the user will have to initiate
reception of the distribution while it is in progress. Accordingly,
as shown in FIG. 17(a), in some embodiments, the packaged data are
distributed in discrete packets 236 of data. The packets 236
include information 238 which enables a user to synchronize with
the data distribution and further enables the user to begin
accessing the data according to the rules. An example of such a
packetized stream of data is shown in FIG. 17(b) wherein the stream
234 consists of discrete packets 236 of data, each packet
containing synchronization data 238.
EXAMPLES
[0326] The following examples indicate some envisioned data and its
packaging and rules. These examples are only intended to show some
of the envisioned uses of the present invention, and are in no way
intended to limit its uses.
[0327] Books
[0328] With reference to FIG. 18(a), a digital book 191 consists of
an abstract 192, an index 194, and various chapters 196. Each
chapter 196 comprises sections 198, and each section comprises text
200 and FIGS. 202. The distributor can decide to package the book
191 such that the abstract 192 and the index 194 are available for
browsing, but all other data are protected (encrypted). If the
rules specify that the text is restricted in certain ways, then the
packaged data structure 108 has the form shown in FIG. 18(b),
wherein encrypted body part 120 includes all chapters 196,
unencrypted body part 122 includes the abstract 192 and index 194,
and encrypted rules 124 contains the encrypted version of the
rules.
[0329] Movies
[0330] With reference to FIG. 19(a), a movie 204 can be made such
that different parts of the movie combine to form either a trailer
206, a G-rated version (from G-rated parts 208), an R-rated version
(formed from G-rated parts 208 and R-rated parts 210) or an X-rated
version (formed from G-rated parts 208, R-rated parts 210 and
X-rated parts 212). The packaged data structure 108 for this movie
has the form shown in FIG. 19(b), wherein encrypted body part 120
includes all the G, R and X-rated parts 208-212, unencrypted body
part 122 includes the trailer 206, and encrypted rules 124 contains
the encrypted version of the age-based rules which control viewing
of the various versions of the movie.
[0331] In one embodiment, as shown in FIG. 19(c), a movie may be
released with a main body 207 (having elements common to all three
versions) and sections for each of the G, R and X-rated parts (208,
210, 212, respectively). Sections of the movie are selected from
one of the rated parts, depending on the permission level (G, R or
X) set. FIG. 19(d) shows packaged data structure 108 for such an
arrangement.
[0332] Software
[0333] With reference to FIG. 20(a), a software program such as,
for example, a word-processor 214 may include a controlled file
access part 216, an editor 218, a grammar checker 220, and other
features 222. The rules obtained by the user will govern the
features of the software that may be used and the quantities of
data that may be processed. The rules shown in FIG. 20(c) indicate
that the user may not employ the grammar checker and may operate on
no more than nine files. The packaged data structure for this
software (without rules) 150 is shown in FIG. 20(b), wherein
encrypted body part 120 includes the file access mechanism 216, the
grammar checker 220 and various other functions 222, and
unencrypted body part 122 includes the editor 218. The encrypted
rules 124 are shown separately in FIG. 20(c).
[0334] Documents
[0335] With reference to FIG. 21(a), a document such as a legal
document 224 comprises paragraphs 226 of words 228. In order to
limit access to non-redacted portions of the document, the rules
would require blacking out all redacted words. Accordingly, the
corresponding packaged data structure is shown in FIG. 21(b),
wherein encrypted body part 120 includes the redacted portions of
the document and unencrypted body part 122 contains the
non-redacted portions of the document.
[0336] Map Image Data
[0337] With reference to FIG. 22(a), map image data 230 may be
available at three resolutions (high, medium and low). The rules
may specify that people with a security clearance of greater than
"top-secret" can view the data at high resolution, and all
non-military users can only view the map data at low resolution.
The corresponding packaged data structure is shown in FIG. 22(b),
wherein encrypted body part 120 includes all data beyond low
resolution (that is, those data required for medium and high
resolution) and unencrypted body part 122 contains the low
resolution data.
[0338] Global Positioning System (GPS) Software
[0339] With reference to FIG. 23(a), GPS software includes an
output routine 232 which can produce output at various degrees of
accuracy. The degree of accuracy depends on the security clearance
of the user. A corresponding packaged data structure is shown in
FIG. 23(b), wherein encrypted body part 120 includes the resolution
calculation routine 232 and unencrypted body part 122 contains the
other parts of the GPS software 230.
[0340] Relationship Among Rule Sets
[0341] In some embodiments, the access mechanism may be supplied
with a set of rules built-in. In such an access mechanism the
built-in rules might include rules that can or cannot be overruled
(made less restrictive) by rules provided with packaged data. These
initial rules can perform a number of functions and implement a
number of policies. As examples, the access mechanisms provided in
controlled output devices can include built-in rules (that cannot
be overruled) which limit the device only to being an output
device; or, the access mechanism provided with a VCR or a videodisc
player can include rules (that cannot be overruled) which require
the device to enforce the copyright laws of the country in which
the device is sold. Whether or not internal built-in rules can be
overruled by rules provided externally can be specified in the
internal rules themselves.
[0342] While the present invention may be used to protect
intellectual property by controlling access to that property, the
mechanisms discussed herein are technical in nature and are
independent of any form of legal protection--a purely technological
approach has been presented to controlling access to data. Indeed,
the invention offers the intellectual property owner the
opportunity to restrict access and use of his or her data beyond
the protections that may be available in law. The protection
offered by the present invention may be used to enforce rights in
intellectual property whether the protection at law is categorized
as copyright, trade secret, contract, or something else. The
cost-benefit tradeoff of seeking protection at law must be made by
those with a vested interest in the intellectual property.
[0343] Typical computer systems are implemented at various levels,
each level effectively defining a different virtual machine.
Generally, each level of implementation can access the levels below
it. In many systems it is desirable to have each level only access
the level immediately below it. In that way, various policies can
be enforced.
[0344] Typically the higher level virtual machines are implemented
in software and the lower level machines are implemented in
hardware. However, there is no precise hardware/software boundary
between levels.
[0345] With reference to FIG. 24, for example, a computer system
has a high-level application environment (level L4). These
applications invoke (call) operating system level (L3) processes to
perform various system functions. The OS level (L3) processes in
turn invoke lower-level Basic Input/Output System (BIOS) machine
dependent instructions as required (level L2). Note that
application level (L4) programs might be permitted to bypass the OS
level (L3) and invoke BIOS level (L2) processes directly, thereby
avoiding any OS level (L3) policy checking and enforcement.
[0346] As an example, an application (executing a level L4) program
which wishes to open a particular named file would invoke an
operating system "open" procedure for that named file. The OS
determines the location of the file (using, for example, an
internal map between file names and locations) and then invokes a
lower level (L2) BIOS routine to perform the actual seek to the
file and the open and read. However, the application program might
be permitted to bypass the operating system's "open" process and
invoke the BIOS routines directly.
[0347] It is desirable to implement the access control mechanisms
of the present invention at a low level, preferably at or below the
BIOS level (level L1). This prevents users from by-passing the
access control mechanisms of the invention and thereby
circumventing the rule enforcement.
[0348] Thus, a system for controlling access and distribution of
digital property is provided. One skilled in the art will
appreciate that the present invention can be practiced by other
than the described embodiments, which are presented for purposes of
illustration and not limitation, and the present invention is
limited only by the claims that follow.
* * * * *