Method of encoding information using a position-based encoding scheme

• US 6,301,360 B1
• Filed: 11/25/1997
• Issued: 10/09/2001
• Est. Priority Date: 06/01/1995
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Latocha, Wanda, Schütt, Dieter, Karls, Ingolf, Bocionek, Siegfried
• Primary Examiner(s): Wright, Norman M.
• Assistant Examiner(s): Seal, James
• Application Number:
  US08/973,062
• Time in Patent Office: 1,414 Days
• Field of Search: 380/54, 380/28, 713/176
• US Class Current: 380/28
• CPC Class Codes: G09C 5/00 Ciphering apparatus or methods not provided for in the preceding groups, e.g. involving the concealment or deformation of graphic data such as designs, written or printed messages
• CPC Class Codes: H04L 2209/60 Digital content management, e.g. content distribution
• CPC Class Codes: H04L 9/001 using chaotic signals
• CPC Class Codes: H04N 1/32203 Spatial or amplitude domain methods H04N1/32309 takes precedence
• CPC Class Codes: H04N 1/32229 with selective or adaptive application of the additional information, e.g. in selected regions of the image H04N1/32213 takes precedence
• CPC Class Codes: H04N 1/32245 Random or pseudorandom selection of pixels
• CPC Class Codes: H04N 1/32251 in multilevel data, e.g. greyscale or continuous tone data
• CPC Class Codes: H04N 2201/327 which are undetectable to the naked eye, e.g. embedded codes

Abstract

Data sequences comprised of figure-coded units, such as text comprised of ASCII characters, are encoded into another data entity, such as a pixel based image. The encoding implements a positionally-based encoding scheme in which values of the data entity (basic matrix) upon which the data sequences are to be encoded is used. The position for values to be changed in the basic matrix are determined by a reversible function, and the encoding value that these values are changed by may be 1, another arbitrary number, or determined by a formula. The counterpart to the reversible function is known by an intended receiver of the encoded data for decoding purposes. The basic matrix may be generated utilizing a suitably complex function, such as a chaos function, with parameters known only to the sender and receiver.

Claims

1. A method for encoding sequences of figure-coded data units which are numerical data to be encoded and producing an encoded numerical data sequence comprising:

generating said sequence of numerical data to be encoded as a numerical data set and providing said sequence of numerical data to an input of an information processing unit;

filling cells contained within a multi-dimensional matrix with values by said information processing unit, wherein said values are calculated by applying a first feedback function to a cell index which specifies a position of a cell within said matrix, and wherein said first feedback function is implemented within said information processing unit;

encoding a first number from said sequence of numerical data to be encoded by changing a first value of a cell of said matrix by a first encoding value, and calculating a first position of said cell containing said first value by applying a first reversible function to said first number from said sequence;

encoding a second number from said sequence by changing a second value of a cell of said matrix by a second encoding value determined as a function of a numerical count of previously encoded numbers from said sequence, and calculating a second position of said cell containing said second value by applying a second reversible function to both said first number and said second number; and

producing said encoded numerical data sequence by outputting said matrix representing said encoded numerical data sequence, which is a post-encoding operation matrix, from an output of said information processing unit.

2. The method according to claim 1, wherein:

said step of encoding a first number further comprises;

combining, after starting from a starting cell of said matrix, cell indices of said starting cell with said first number from said sequence in an unambiguous and reversible manner, producing cell indices of a first encoding cell; and

wherein

said step of encoding a second number further comprises;

changing said second value of a cell of said matrix whose cell indices are determined by combining said cell indices of said first encoding cell with said second number from said sequence in said unambiguous and reversible manner.

3. The method according to claim 1, wherein:

said first feedback function is a chaos function; and

said method further comprising the step of;

using a first function value supplied by said chaos function for filling said matrix with values, wherein said first function value is supplied by said chaos function after repeated iterations, depending on a variation of said chaos function after exceeding a predetermined limit value.

4. The method according to claim 3, further comprising the step of:

using a first function value supplied by said chaos function for filling said matrix with values, wherein said first function value is supplied by said chaos function after a predefined number of repeated iterations where said predetermined limit value cannot be met.

5. The method according to claim 2, wherein said step of producing cell indices of said first encoding cell further comprises the step of adding said first number to at least one of said matrix indices.

6. The method according to claim 1, wherein said encoding value is the number 1.

7. The method according to claim 1, further comprising the step of determining said encoding value by a chaos function.

8. The method according to claim 1, further comprising the step of:

combining, said post-encoding operation matrix with data on an image medium using an element-wise operation for a purpose selected from the group consisting of authentication or identification.

9. The method according to claim 1, further comprising the step of:

combining, using an element-wise operation, said post-encoding operation matrix with an image data record for a purpose selected from the group consisting of authentication or identification.

13. The method according to claim 1, wherein said first reversible function is identical to said second reversible function.

10. A method for encoding sequences of figure-coded data units which are numerical data to be encoded and producing an encoded numerical data sequence comprising:

generating said sequence of numerical data to be encoded as a numerical data set and providing said sequence of numerical data to an input of an information processing unit;

filling cells contained within a multi-dimensional matrix with values by said information processing unit, wherein said values represent color or gray-scale values of an image;

encoding a first number from said sequence of numerical data to be encoded by changing a first value of a cell of said matrix by a first encoding value, and calculating a position of said cell containing said first value by applying a first reversible function to said first number from said sequence;

encoding a second number from said sequence by changing a second value of a cell of said matrix by a second encoding value determined as a function of a numerical count of previously encoded numbers from said sequence, and calculating a position of said cell containing said second value by applying a second reversible function to both said first number and said second number; and

producing said encoded numerical data sequence by outputting said matrix representing said encoded numerical data sequence, which is a post-encoding operation matrix, from an output of said information processing unit.

11. The method according to claim 10, wherein said encoding value is scaled such that a changed value of a cell can represent the number of possible color or gray-scale values.

12. A method for encoding and decoding sequences of figure-coded data units which are numerical data and producing an encoded numerical data sequence comprising:

generating said sequence of numerical data to be encoded as a numerical data set and providing said sequence of numerical data to an input of an information processing unit;

filling cells contained within a multi-dimensional matrix with values by said information processing unit, wherein said values are calculated by applying a first feedback function to a cell index which specifies a position of a cell within said matrix, and wherein said first feedback function is implemented within said information processing unit;

encoding a first number from said sequence of numerical data to be encoded by changing a first value of a cell of said matrix by a first encoding value, and calculating a first position of said cell containing said first value by applying a first reversible function to said first number from said sequence;

encoding a second number from said sequence by changing a second value of a cell of said matrix by a second encoding value determined as a function of a numerical count of previously encoded numbers from said sequence, and calculating a second position of said cell containing said second value by applying a second reversible function to both said first number and said second number;

producing said encoded numerical data sequence by outputting said matrix representing said encoded numerical data sequence, which is a post-encoding operation matrix, from an output of said information processing unit;

filling cells, by a receiver, contained within a multi-dimensional output matrix with values by an information separating processing unit for decoding said encoded numerical data, wherein said values are calculated by applying a function related to said first feedback function and its application to said multi-dimensional matrix;

comparing said encoded numerical data value by value with said output matrix, producing identified changed values;

applying a first inverse reversible function related to said first reversible function to said first calculated position for decoding a first changed value of said identified changed values, thereby finding said first number of said sequence;

applying a second inverse reversible function related to said second reversible function to a second changed value of said identified changed values, thereby finding said second number of said sequence in a reverse order from said encoding of said sequence, producing a decoded sequence; and

outputting from an output of said information separating processing unit said decoded sequence.