US5701342A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Complex document security
Assignee: Australian Government
•
Filing: 1993-12-14
•
Granted: 1997-12-23
•
Expires: 2013-12-14
Abstract
Abstract A method and means to control the degree to which the presence of covert information may be reduced, eliminated or corrupted in documents created on a computer device (particularly complex documents) before the document is transmitted outside a secure environment in which the document is created. The process of handling a document in a secure environment comprises the preferred step of displaying the document or a predetermined portion thereof in a manner which conforms to the rule that no pixel of the display is written to more than once for the current portion of the document being displayed. Preferably the method includes the steps of creating a document, transforming the document into an intermediate form by defining the content and structure of the document using a predetermined set of document describers, applying the intermediate form of the document to at least one filter adapted to eliminate or corrupt the content and form of any covert information contained within the intermediate form of the document followed by the previously described step of displaying the document in the manner described above.
Inventors
- 👤 Mark Stephen Anderson
- 👤 John Desborough Yesberg
- 👤 Michael Pope
- 👤 Lisa Nayda
- 👤 Ken Hayman
- 👤 Brendan Beahan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 22:39
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/32; H04N1/32101; H04N1/32128; H04L; H04L51/00; H04L51/21; H04L51/212; H04L63/00; H04L63/12; H04L63/123; H04N2201/00; H04N2201/32; H04N2201/3201; H04N2201/3225; H04N2201/3233; H04N2201/3235; H04N2201/3236; H04N2201/3278
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
88 words
A method of handling a document for transmission external of a secure computer environment, comprising the steps of: (a) applying a document to at least one filter to eliminate or corrupt the content or form of covert information contained within said document; (b) displaying to a viewer said filtered document or a predetermined portion thereof in a trusted manner; and (c) communicating said filtered document in a secure manner, external of said secure computer environment, if said filtered and displayed document appears to be acceptable to said viewer.
Claim 2
Independent Claim
88 words
A method of handling a document for transmission external of a secure computer environment, comprising the steps of: (a) applying a document to at least one filter to eliminate or corrupt the content or form of covert information contained within said document; (b) displaying to a viewer said filtered document or a predetermined portion thereof in a trusted manner; and (c) communicating said filtered document in a secure manner, external of said secure computer environment, if said filtered and displayed document appears to be acceptable to said viewer.
Claim 3
Dependent Claim
37 words
A method of handling a document in accordance with claim 1 where step (c) further comprises: associating with said filtered document a seal which indicates that said document can be communicated external of said secure computer environment.
Claim 4
Dependent Claim
51 words
A method of handling a document in accordance with claim 1, where step (b) further comprises: displaying said filtered document or a predetermined portion thereof in a trusted manner so that no pixel of the display is written to more than once for the current portion of the document being displayed.
Claim 5
Dependent Claim
47 words
A method in accordance with claim 2, where step (b) further comprises displaying said filtered document or a predetermined portion thereof in a trusted manner so that no pixel of the display is written to more than once for the current portion of the document being displayed.
Claim 6
Dependent Claim
44 words
A method of handling a document in accordance with claim 1 with the following step being performed before step (b): (d) checking said filtered document in a trusted manner to ensure only a predetermined form of said document is passed to the next step.
Claim 7
Dependent Claim
44 words
A method of handling a document in accordance with claim 2 with the following step being performed before step (b): (e) checking said filtered document in a trusted manner to ensure only a predetermined form of said document is passed to the next step.
Claim 8
Dependent Claim
44 words
A method of handling a document in accordance with claim 3, with the following step being performed before step (b): (f) checking said filtered document in a trusted manner to ensure only a predetermined form of said document is passed to the next step.
Claim 9
Dependent Claim
44 words
A method of handling a document in accordance with claim 4, with the following step being performed before step (b): (g) checking said filtered document in a trusted manner to ensure only a predetermined form of said document is passed to the next step.
Claim 10
Dependent Claim
40 words
A method of handling a document in accordance with claim 1 where in step (a) at least one of said filters is trusted and adapted to eliminate or corrupt the content and form of covert information contained within said document.
Claim 11
Dependent Claim
40 words
A method of handling a document in accordance with claim 2 where in step (a) at least one of said filters is trusted and adapted to eliminate or corrupt the content and form of covert information contained within said document.
Claim 12
Dependent Claim
40 words
A method of handling a document in accordance with claim 3 where in step (a) at least one of said filters is trusted and adapted to eliminate or corrupt the content and form of covert information contained within said document.
Claim 13
Dependent Claim
40 words
A method of handling a document in accordance with claim 4 where in step (a) at least one of said filters is trusted and adapted to eliminate or corrupt the content and form of covert information contained within said document.
Claim 14
Independent Claim
156 words
A method of handling a document for transmission external of a secure computer environment, comprising the steps of: (a) applying a document to at least one filter to eliminate or corrupt the content or form of covert information contained with said document; (b) displaying to a viewer said filtered document or a predetermined portion thereof in a trusted manner; (c) communicating said filtered document, in a secure manner, if said filtered and displayed document appears acceptable to said viewer, by associating with said filtered document a seal which indicates that said document can be communicated external of said secure computer environment; (d) receiving with a trusted gateway device located within said secure computer environment said document with its associated seal; (e) checking the validity of said seal with a trusted verification means, and if and only if said seal is validly associated with said document; and (f) communicating said document external of said secure computer environment.
Claim 15
Independent Claim
156 words
A method of handling a document for transmission external of a secure computer environment, comprising the steps of: (a) applying a document to at least one filter to eliminate or corrupt the content or form of covert information contained with said document; (b) displaying to a viewer said filtered document or a predetermined portion thereof in a trusted manner; (c) communicating said filtered document, in a secure manner, if said filtered and displayed document appears acceptable to said viewer, by associating with said filtered document a seal which indicates that said document can be communicated external of said secure computer environment; (d) receiving with a trusted gateway device located within said secure computer environment said document with its associated seal; (e) checking the validity of said seal with a trusted verification means, and if and only if said seal is validly associated with said document; and (f) communicating said document external of said secure computer environment.
Claim 16
Dependent Claim
18 words
A method according to claim 13, wherein step (f) further comprises communicating said document with its associated seal.
Claim 17
Dependent Claim
39 words
A method according to claim 14, and comprising the further steps of: g) receiving said document and its associated seal external of said secure computer environment; and h) disassociating said seal and extracting application specific data from said seal.
Claim 18
Independent Claim
60 words
A method in accordance with any of claims 1-16 and 13-15, with the addition of the following step before any other step: (i) transforming said document into an intermediate form by defining the content and structure of said document using a predetermined set of document describers; and with all subsequent steps operating on the transformed document rather than said document.
Claim 19
Independent Claim
97 words
A method in accordance with any of claims 1-15 and 13-15, with the following step being performed before any other step: (j) transforming said document into an intermediate form by defining the content and structure of said document using a predetermined set of document describers; and with the following additional step being performed after said transformed and filtered document is received external of said secure computer environment: (k) further transforming said transformed and filtered document in the reverse fashion to step (j) to produce a final document in a form useful to the recipients of the document.
Claim 20
Independent Claim
145 words
A method of handling a document for transmission external of a secure computer environment, comprising the steps of: (a) applying a document to at least one filter to eliminate or corrupt the content or form of covert information contained within said document, wherein if not already a digital image, at least one of said filters converts said document or a portion thereof into a first digital image; (b) converting said document or said first digital image into an analog form; (c) converting said analog form into a second digital image, which comprises the filtered document or a portion thereof; (d) displaying to a viewer said filtered document or a predetermined portion thereof in a trusted manner; and (e) communicating said filtered document in a secure manner, external of said secure computer environment, if said filtered and displayed document appears to be acceptable to said viewer.
Claim 21
Independent Claim
145 words
A method of handling a document for transmission external of a secure computer environment, comprising the steps of: (a) applying a document to at least one filter to eliminate or corrupt the content or form of covert information contained within said document, wherein if not already a digital image, at least one of said filters converts said document or a portion thereof into a first digital image; (b) converting said document or said first digital image into an analog form; (c) converting said analog form into a second digital image, which comprises the filtered document or a portion thereof; (d) displaying to a viewer said filtered document or a predetermined portion thereof in a trusted manner; and (e) communicating said filtered document in a secure manner, external of said secure computer environment, if said filtered and displayed document appears to be acceptable to said viewer.
Claim 22
Dependent Claim
35 words
A method in accordance with claim 18, wherein said second digital image is of equal or lesser resolution than said first digital image, said second digital image comprising the filtered document or a potion thereof.
Claim 23
Dependent Claim
17 words
A method in accordance with claim 18, wherein said at least one filter is a trusted filter.
Claim 24
Dependent Claim
35 words
A method in accordance with claim 20, wherein said second digital image is of equal or lesser resolution than said first digital image, said second digital image comprising the filtered document or a portion thereof.
Claim 25
Independent Claim
172 words
A method of handling a document for transmission external of a secure computer environment, comprising the steps of: (a) applying a document to at least one filter to eliminate or corrupt the content or form of covert information contained within said document, wherein if not already a digital image, at least one of said filters converts said document or a portion thereof into a first digital image; (b) converting said document or said first digital image into a second digital image such that one or more pixel values from said first digital image is combined with itself or a predetermined value to produce one or more pixel values in said second digital image wherein said second digital image comprises said filtered document or a portion thereof; (c) displaying to a viewer said filtered document or a predetermined portion thereof in a trusted manner; and (d) communicating said filtered document in a secure manner, external of said secure computer environment, if said filtered and displayed document appears to be acceptable to said viewer.
Claim 26
Independent Claim
172 words
A method of handling a document for transmission external of a secure computer environment, comprising the steps of: (a) applying a document to at least one filter to eliminate or corrupt the content or form of covert information contained within said document, wherein if not already a digital image, at least one of said filters converts said document or a portion thereof into a first digital image; (b) converting said document or said first digital image into a second digital image such that one or more pixel values from said first digital image is combined with itself or a predetermined value to produce one or more pixel values in said second digital image wherein said second digital image comprises said filtered document or a portion thereof; (c) displaying to a viewer said filtered document or a predetermined portion thereof in a trusted manner; and (d) communicating said filtered document in a secure manner, external of said secure computer environment, if said filtered and displayed document appears to be acceptable to said viewer.
Claim 27
Dependent Claim
69 words
A method in accordance with claim 22, wherein said second digital image is of equal or lesser resolution such that one or more pixel values or portions of pixel values from said first digital image are selected and/or combined to produce one or more pixel values or portions of pixel values in said second digital image wherein said second digital image comprises said filtered document or a portion thereof.
Claim 28
Dependent Claim
53 words
A method in accordance with claim 22 or 23, wherein said one or more pixel values or portions of pixel values from said first digital image is selected and/or combined in a random or pseudo-random manner to produce one or more pixel values or portions of pixel values in said second digital image.
Claim 29
Dependent Claim
17 words
A method in accordance with claim 22, wherein said at least one filter is a trusted filter.
Claim 30
Dependent Claim
70 words
A method in accordance with claim 25, wherein said second digital image is of equal or lesser resolution such that one or more pixel values or portions of pixel values from said first digital image is selected and or combined to produce one or more pixel values or portions of pixel values in said second digital image wherein said second digital image comprises said filtered document or a portion thereof.
Claim 31
Dependent Claim
54 words
A method in accordance with claim 25 or 26, wherein said one or more pixel values or portions of pixel values from said first digital image is selected and or combined in a random or pseudo-random manner to produce one or more pixel values or portions of pixel values in said second digital image.
Claim 32
Independent Claim
103 words
A method of a handling a document for transmission external of a secure computer environment, comprising the steps of: (a) displaying said document or a predetermined portion thereof in a trusted manner; (b) applying said document or a predetermined portion thereof to at least one filter to eliminate or corrupt the content or form of covert information contained within said document or portion thereof wherein at least one of said filters is trusted; and (c) communicating said filtered and displayed document in a secure manner external of said secure computer environment, if said displayed document appears acceptable to the viewer of the document.
Claim 33
Independent Claim
103 words
A method of a handling a document for transmission external of a secure computer environment, comprising the steps of: (a) displaying said document or a predetermined portion thereof in a trusted manner; (b) applying said document or a predetermined portion thereof to at least one filter to eliminate or corrupt the content or form of covert information contained within said document or portion thereof wherein at least one of said filters is trusted; and (c) communicating said filtered and displayed document in a secure manner external of said secure computer environment, if said displayed document appears acceptable to the viewer of the document.
Claim 34
Dependent Claim
37 words
The method of handling a document in accordance with claim 28, where step (c) further comprises: associating with said filtered document a seal which indicates that said document can be communicated external of said secure computer environment.
Claim 35
Dependent Claim
51 words
The method of handling a document in according with claim 28, where step (a) further comprises: displaying said filtered document or a predetermined portion thereof in a trusted manner so that no pixel of the display is written to more than once for the current portion of the document being displayed.
Claim 36
Dependent Claim
51 words
The method of handling a document in accordance with claim 24, where step (a) further comprises: displaying said filtered document or a predetermined portion thereof in a trusted manner so that no pixel of the display is written to more than once for the current portion of the document being displayed.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-12-22 | 2001-06-23 | 2001-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-12-22 | 2005-06-23 | 2005-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-12-22 | 2009-06-23 | 2009-12-23 | $7700.00 | Window Closed / Lapsed |