US6094483A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Secure encryption and hiding of data and messages in images
Assignee: Research Foundation of the State University of New York
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Filing: 1997-08-06
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Granted: 2000-07-25
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Expires: 2017-08-06
Abstract
Abstract A method of encryption features the steps of first encrypting a message and then hiding (embedding) it within a digital image carrier. This is accomplished by only slightly changing the gray levels of the image carrier. The changes are imperceptible to the human eye, because they appear as random thermal noise that is commonly present in digitized images.
Inventors
- 👤 Jiri Fridrich
- 👤 Richard J. Simard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 11:30
CPC Classifications
G; G06; G06T; G06T1/00; G06T1/0021; H; H04; H04N; H04N1/00; H04N1/32; H04N1/32101; H04N1/32144; H04N1/32149; H04N1/32203; H04N1/32208; H04N1/32229; H04N1/32245; H04N19/00; G06T2201/00; G06T2201/005; G06T2201/0051; H04N2201/00; H04N2201/32; H04N2201/3201; H04N2201/3225; H04N2201/3233; H04N2201/3269; H04N2201/327; H04N2201/328; H04N2201/3281
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
123 words
A method of encrypting/embedding and decrypting/extracting a secret image, comprising the steps of: a) encrypting a secret image of N×M pixels with g ij gray levels using a chaotic map; b) choosing some carrier image of 2N×2M pixels with g ij gray levels; c) modifying said carrier image according to a pseudocode, including the further steps of: i) for each pixel P=(i, j) of the secret image, converting the gray level g ij to a base 4 representation, t1, t2, t3, t4, where t1+t2*4+t3*16+t4*64=g ij ; and ii) modifying the gray levels of pixels (2i, 2j), (2i+1, 2j), (2i, 2j+1), (2i+1, 2j+1) of the carrier image by 2-t1, 2-t2, 2-t3, and 2-t4, respectively; and d) sending said modified carrier image to a recipient.
Claim 2
Independent Claim
123 words
A method of encrypting/embedding and decrypting/extracting a secret image, comprising the steps of: a) encrypting a secret image of N×M pixels with g ij gray levels using a chaotic map; b) choosing some carrier image of 2N×2M pixels with g ij gray levels; c) modifying said carrier image according to a pseudocode, including the further steps of: i) for each pixel P=(i, j) of the secret image, converting the gray level g ij to a base 4 representation, t1, t2, t3, t4, where t1+t2*4+t3*16+t4*64=g ij ; and ii) modifying the gray levels of pixels (2i, 2j), (2i+1, 2j), (2i, 2j+1), (2i+1, 2j+1) of the carrier image by 2-t1, 2-t2, 2-t3, and 2-t4, respectively; and d) sending said modified carrier image to a recipient.
Claim 3
Dependent Claim
122 words
The method of encrypting/embedding and decrypting/extracting a secret image in accordance with claim 1, further comprising the steps of: e) extracting said encrypted secret image from said modified carrier image by subtracting said modified carrier image of step (c) from said original carrier image using a pseudocode, comprising the further steps of: i) for each (i, j), 0≦i≦N-1, and 0≦j≦M-1, taking the four values at positions (2i, 2j), (2i+1, 2j), (2i, 2j+1), (2i+1, 2j+1) of the subtracted image to be t1, t2, t3, t4, respectively; and ii) recovering the gray level g ij of said encrypted N×M image by applying the formula g ij =t1+4*t2+16*t3+64*t4, where 0≦t1, t2, t3, t4≦3; and f) decrypting said encrypted image and recovering said original secret image.
Claim 4
Independent Claim
84 words
A method of hiding a message in an information carrier, the steps comprising: a) encrypting a message with the use of a chaotic baker map; b) choosing an information carrier comprising a set of pixels; c) coding the shade or color level of said encrypted message using a set of pixels in said information carrier; d) modifying said shade or color level of each of said pixels of said coded message by one of a plurality of values; and e) transmitting said modified message.
Claim 5
Independent Claim
84 words
A method of hiding a message in an information carrier, the steps comprising: a) encrypting a message with the use of a chaotic baker map; b) choosing an information carrier comprising a set of pixels; c) coding the shade or color level of said encrypted message using a set of pixels in said information carrier; d) modifying said shade or color level of each of said pixels of said coded message by one of a plurality of values; and e) transmitting said modified message.
Claim 6
Dependent Claim
20 words
The method of hiding a message in an information carrier in accordance with claim 3, wherein said message comprises text.
Claim 7
Dependent Claim
21 words
The method of hiding a message in an information carrier in accordance with claim 3, wherein said message comprises an image.
Claim 8
Dependent Claim
23 words
The method of hiding a message in an information carrier in accordance with claim 4, wherein said information carrier comprises a digital image.
Claim 9
Dependent Claim
23 words
The method of hiding a message in an information carrier in accordance with claim 5, wherein said information carrier comprises a digital image.
Claim 10
Dependent Claim
30 words
The method of hiding a message in an information carrier in accordance with claim 7, wherein said shade level of said encrypted message comprise numbers representative of shades of gray.
Claim 11
Dependent Claim
29 words
The method of hiding a message in an information carrier in accordance with claim 7, wherein said color level of said encrypted message comprise numbers representative of unique colors.
Claim 12
Dependent Claim
30 words
The method of hiding a message in an information carrier in accordance with claim 5, wherein said shade level of said encrypted message comprise numbers representative of shades of gray.
Claim 13
Dependent Claim
28 words
The method of hiding a message in an information carrier in accordance with claim 4, wherein said plurality of values comprises the numbers 1, 0, -1 and -2.
Claim 14
Dependent Claim
28 words
The method of hiding a message in an information carrier in accordance with claim 5, wherein said plurality of values comprises the numbers 1, 0, -1 and -2.
Claim 15
Dependent Claim
27 words
The method of hiding a message in an information carrier in accordance with claim 8, wherein said information carrier image comprises 2N×2M pixels with 256 gray levels.
Claim 16
Dependent Claim
26 words
The method of hiding a message in an information carrier in accordance with claim 9, wherein said information carrier image comprises 2N×2M pixels with 256 colors.
Claim 17
Dependent Claim
76 words
The method of hiding a message in an information carrier in accordance with claim 8, wherein said modifying step (d) comprises: i) for each pixel P=(i, j) of the message, converting the gray level g ij to a base 4 representation, t1, t2, t3, t4, where t1+t2*4+t3*16+t4*64=g ij ; and ii) modifying the gray levels of pixels (2i, 2j), (2i+1, 2j), (2i, 2j+1), (2i+1, 2j+1) of the information carrier by 2-t1, 2-t2, 2-t3, and 2-t4, respectively.
Claim 18
Dependent Claim
76 words
The method of hiding a message in an information carrier in accordance with claim 10, wherein said modifying step (d) comprises: i) for each pixel P=(i, j) of the message, converting the gray level g ij to a base 4 representation, t1, t2, t3, t4, where t1+t2*4+t3*16+t4*64=g ij ; and ii) modifying the gray levels of pixels (2i, 2j), (2i+1, 2j), (2i, 2j+1), (2i+1, 2j+1) of the information carrier by 2-t1, 2-t2, 2-t3, and 2-t4, respectively.
Claim 19
Dependent Claim
76 words
The method of hiding a message in an information carrier in accordance with claim 11, wherein said modifying step (d) comprises: i) for each pixel P=(i, j) of the message, converting the gray level g ij to a base 4 representation, t1, t2, t3, t4, where t1+t2*4+t3*16+t4*64=g ij ; and ii) modifying the gray levels of pixels (2i, 2j), (2i+1, 2j), (2i, 2j+1), (2i+1, 2j+1) of the information carrier by 2-t1, 2-t2, 2-t3, and 2-t4, respectively.
Claim 20
Dependent Claim
76 words
The method of hiding a message in an information carrier in accordance with claim 13, wherein said modifying step (d) comprises: i) for each pixel P=(i, j) of the message, converting the gray level g ij to a base 4 representation, t1, t2, t3, t4, where t1+t2*4+t3*16+t4*64=g ij ; and ii) modifying the gray levels of pixels (2i, 2j), (2i+1, 2j), (2i, 2j+1), (2i+1, 2j+1) of the information carrier by 2-t1, 2-t2, 2-t3, and 2-t4, respectively.
References Cited (Backward Citations)
US5748763A
Cited
US5819289A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-07-25 | 2004-01-24 | 2004-07-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-07-25 | 2008-01-24 | 2008-07-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-07-25 | 2012-01-24 | 2012-07-25 | $7700.00 | Window Closed / Lapsed |