Secured signal modification and verification with privacy control

• US 6,256,736 B1
• Filed: 04/13/1998
• Issued: 07/03/2001
• Est. Priority Date: 04/13/1998
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Yeung, Minerva Ming-Yee, Wu, Chai Wah, Tresser, Charles P., Mintzer, Frederick Cole, Coppersmith, Don
• Primary Examiner(s): Barron, Jr., Gilberto
• Assistant Examiner(s): DI LORENZO, ANTHONY
• Application Number:
  US09/059,498
• Time in Patent Office: 1,177 Days
• Field of Search: 380/200, 380/201, 380/206, 713/176, 713/181, 705/58
• US Class Current: 713/176
• CPC Class Codes: G06T 1/0064 Geometric transfor invariant watermarking, e.g. affine transform invariant
• CPC Class Codes: H04N 1/32144 embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
• CPC Class Codes: H04N 1/32213 Modulating the least significant bits of pixels
• CPC Class Codes: H04N 1/32309 in colour image data
• CPC Class Codes: H04N 21/23892 involving embedding information at multiplex stream level, e.g. embedding a watermark at packet level
• CPC Class Codes: H04N 21/8358 involving watermark protecting executable software by watermarking G06F21/16; image watermarking in general G06T1/0021; watermarks inserted in still images for transmission purposes H04N1/32144; inserting watermarks during video coding H04N19/467
• CPC Class Codes: H04N 2201/3214 of a date
• CPC Class Codes: H04N 2201/3215 of a time or duration
• CPC Class Codes: H04N 2201/3225 of data relating to an image, a page or a document
• CPC Class Codes: H04N 2201/3226 of identification information or the like, e.g. ID code, index, title, part of an image, reduced-size image
• CPC Class Codes: H04N 2201/3233 of authentication information, e.g. digital signature, watermark
• CPC Class Codes: H04N 2201/3235 Checking or certification of the authentication information, e.g. by comparison with data stored independently
• CPC Class Codes: H04N 2201/327 which are undetectable to the naked eye, e.g. embedded codes

Abstract

A watermarking scheme which allows the watermarked image to be authenticated by an authentication agent without revealing the human-readable content of the image. There is disclosed an approach which combines privacy control with watermarking and authentication mechanisms. The watermark can be made to be imperceptible to humans. Public key cryptography allows the authentication agent to authenticate without being able to watermark an image.

Claims

1. A method for generating a watermark and using said watermark to authenticate a human-perceptible source data set, comprising the steps of:

extracting higher order bits from said source data set;

applying public key cryptography to said higher order bits to generate an encrypted set of bits;

generating a watermark from said encrypted set of bits;

inserting said watermark into the least significant bits of said source data set, thereby creating a watermarked version of said source data set; and

authenticating and/or allowing other parties to authenticate that a cropped version of said watermark corresponds to said human-perceptible source data set so that cropped images can be recognized as cropped images and authenticated as cropped images and/or that it can be recognized that blocks within the image have been rearranged.

2. The method of claim 1, wherein a third party having said watermarked version alone cannot extract said watermark to apply said watermark to additional source data sets.

12. The method of claim 1, wherein said authenticating step can be performed using said watermarked version alone.

3. A method for generating a watermark and using said watermark to authenticate a human-perceptible source data set, comprising the steps of:

extracting higher order bits from said source data set;

generating a watermark depending on said higher order bits and, optionally, also depending on additional information;

inserting said watermark into the least significant bits of said source data set, thereby creating a watermarked version of said source data set;

authenticating and/or allowing other parties to authenticate that said watermark corresponds to said human-perceptible source data set, wherein said authenticating step is performed on a cropped version of said watermarked version and cropping is detected by said authenticating step; and

extracting and/or allowing other parties to extract some or all of said additional information used to create said watermark.

4. A method for generating a watermark and using said watermark to authenticate a human-perceptible source data set, comprising the steps of:

extracting higher order bits from said source data set;

generating a watermark depending on said higher order bits and, optionally, also depending on additional information;

inserting said watermark into the least significant bits of said source data set, thereby creating a watermarked version of said source data set;

authenticating and/or allowing other parties to authenticate that said watermark corresponds to said human-perceptible source data set, wherein said authenticating step can determine the approximate location of any alteration in said source data set; and

extracting and/or allowing other parties to extract some or all of said additional information used to create said watermark.

5. A method for using watermarks to distribute and authenticate human perceptible source data sets, comprising the steps of:

digitizing and segmenting a human perceptible source data set into a plurality of non-overlapping digitized segments and a corresponding plurality of overlapping digitized segments, wherein each non-overlapping segment is embedded within its corresponding overlapping segment in the same manner, and wherein said digitizing comprises a digital representation of said human perceptible source data set, said digital representation consisting of digital elements, each said element being divided into high order bits and low order bits, said high order bits being sufficient to preserve the human perceptibility of said source data set;

creating a watermarked version of said source data set, wherein said step of creating a watermarked version of said source data set further comprises, for each of said plurality of corresponding segments;

adding privacy control to said high order bits of said overlapping segment, resulting in a data set consisting of encrypted high order bits;

applying a watermarking algorithm to said data set consisting of encrypted high order bits, said algorithm resulting in a data set reduced in size;

mapping said reduced data set onto the low order bits of said non-overlapping segment, thereby replacing said low order bits, said reduction in size being sufficient that said mapping results in spare low order bits being left over, some of said spare low order bits being used to indicate watermark attributes, wherein said watermark attributes are the same for all said segments, and wherein spare low order bits containing said watermark attributes are dispersed within said segments in a standardized way so as to be usable as locators;

distributing said watermarked data set;

applying a privacy release algorithm to said watermarked data set; and

authenticating said watermarked data set, wherein said authenticating step is performed on a cropped portion of said watermarked data set, said watermark attributes being used to align said over-lapping segments.

6. A method for using watermarks to distribute and authenticate human perceptible source data sets, comprising the steps of:

digitizing and segmenting a human perceptible source data set into a plurality of non-overlapping digitized segments and a corresponding plurality of overlapping digitized segments, wherein each non-overlapping segment is embedded within its corresponding overlapping segment in the same manner, and wherein said digitizing comprises a digital representation of said human perceptible source data set, said digital representation consisting of digital elements, each said element being divided into high order bits and low order bits, said high order bits being sufficient to preserve the human perceptibility of said source data set;

creating a watermarked version of said source data set, wherein said step of creating a watermarked version of said source data set further comprises, for each of said plurality of corresponding segments;

adding privacy control to said high order bits of said overlapping segment, resulting in a data set consisting of encrypted high order bits;

applying a watermarking algorithm to said data set consisting of encrypted high order bits, said algorithm resulting in a data set reduced in size;

mapping said reduced data set onto the low order bits of said non-overlapping segment, thereby replacing said low order bits, said reduction in size being sufficient that said mapping results in spare low order bits being left over some of said spare low order bits being used to indicate watermark attributes;

distributing said watermarked data set;

applying a privacy release algorithm to said watermarked data set; and

authenticating said watermarked data set, wherein said authenticating step is performed on a cropped portion of said watermarked data set, and wherein a small fixed synchronization pattern is embedded in said spare low order bits for use in aligning said over-lapping segments.

7. An apparatus for generating a watermark and using said watermark to authenticate a human-perceptible source data set, comprising:

means for extracting higher order bits from said source data set;

means for applying public key cryptography to said higher order bits to generate an encrypted set of bits;

means for generating a watermark from said encrypted set of bits;

means for inserting said watermark into the least significant bits of said source data set, thereby creating a watermarked version of said source data set; and

means for authenticating and/or allowing other parties to authenticate that a cropped version of said watermark corresponds to said human-perceptible source data set so that cropped images can be recognized as cropped images and authenticated as cropped images and/or that it can be recognized that blocks within the image have been rearranged.

8. An apparatus for generating a watermark and using said watermark to authenticate a human-perceptible source data set, comprising:

means for extracting higher order bits from said source data set;

means for generating a watermark depending on said higher order bits and, optionally, also depending on additional information;

means for inserting said watermark into the least significant bits of said source data set, thereby creating a watermarked version of said source data set;

means for authenticating and/or allowing other parties to authenticate that said watermark corresponds to said human-perceptible source data set, wherein said authenticating means operates on a cropped version of said watermarked version and cropping is detected by said authenticating means; and

means for extracting and/or allowing other parties to extract some or all of said additional information used to create said watermark.

9. An apparatus for generating a watermark and using said watermark to authenticate a human-perceptible source data set, comprising:

means for extracting higher order bits from said source data set;

means for generating a watermark depending on said higher order bits and, optionally, also depending on additional information;

means for inserting said watermark into the least significant bits of said source data set, thereby creating a watermarked version of said source data set;

means for authenticating and/or allowing other parties to authenticate that said watermark corresponds to said human-perceptible source data set, wherein said authenticating means can determine the approximate location of any alteration in said source data set; and

means for extracting and/or allowing other parties to extract some or all of said additional information used to create said watermark.

10. An apparatus for using watermarks to distribute and authenticate human perceptible source data sets, comprising:

means for digitizing and segmenting a human perceptible source data set into a plurality of non-overlapping digitized segments and a corresponding plurality of overlapping digitized segments wherein each non-overlapping segment is embedded within its corresponding overlapping segment in the same manner, and wherein said digitizing means comprises a digital representation of said human perceptible source data set, said digital representation consisting of digital elements, each said element being divided into high order bits and low order bits, said high order bits being sufficient to preserve the human perceptibility of said source data set;

means for creating a watermarked version of said source data set, wherein said means for creating a watermarked version of said source data set further comprises, for each of said plurality of corresponding segments;

means for adding privacy control to said high order bits of said overlapping segment, resulting in a data set consisting of encrypted high order bits;

means for applying a watermarking algorithm to said data set consisting of encrypted high order bits, said algorithm resulting in a data set reduced in size; and

means for mapping said reduced data set onto the low order bits of said non-overlapping segment thereby replacing said low order bits, said reduction in size being sufficient that said mapping results in spare low order bits being left over, some of said spare low order bits being used to indicate watermark attributes, wherein said watermark attributes are the same for all said segments, and wherein spare low order bits containing said watermark attributes are dispersed within said segments in a standardized way so as to be usable as locators;

means for distributing said watermarked data set;

means for applying a privacy release algorithm to said watermarked data set; and

means for authenticating said watermarked data set, wherein said authenticating means operates on a cropped portion of said watermarked data set, said watermark attributes being used to align said over-lapping segments.

11. An apparatus for using watermarks to distribute and authenticate human perceptible source data sets, comprising:

means for digitizing and segmenting a human perceptible source data set into a plurality of non-overlapping digitized segments and a corresponding plurality of overlapping digitized segments, wherein each non-overlapping segment is embedded within its corresponding overlapping segment in the same manner, and wherein said digitizing means comprises a digital representation of said human perceptible source data set, said digital representation consisting of digital elements, each said element being divided into high order bits and low order bits, said high order bits being sufficient to preserve the human perceptibility of said source data set;

means for creating a watermarked version of said source data set, wherein said means for creating a watermarked version of said source data set further comprises, for each of said plurality of corresponding segments;

means for adding privacy control to said high order bits of said overlapping segment, resulting in a data set consisting of encrypted high order bits;

means for applying a watermarking algorithm to said data set consisting of encrypted high order bits, said algorithm resulting in a data set reduced in size; and

means for mapping said reduced data set onto the low order bits of said non-overlapping segment, thereby replacing said low order bits, said reduction in size being sufficient that said mapping results in spare low order bits being left over, some of said spare low order bits being used to indicate watermark attributes;

means for distributing said watermarked data set;

means for applying a privacy release algorithm to said watermarked data set; and

means for authenticating said watermarked data set, wherein said authenticating means operates on a cropped portion of said watermarked data set, and wherein a small fixed synchronization pattern is embedded in said spare low order bits for use in aligning said over-lapping segments.