Steganographic method and device

Abstract

An apparatus and method for encoding and decoding additional information into a stream of digitized samples in an integral manner. The information is encoded using special keys. The information is contained in the samples, not prepended or appended to the sample stream. The method makes it extremely difficult to find the information in the samples if the proper keys are not possessed by the decoder. The method does not cause a significant degradation to the sample stream. The method is used to establish ownership of copyrighted digital multimedia content and provide a disincentive to piracy of such material.

1 - 25 . (canceled) 
     
     
         26 . A computer implemented method for encoding a digital sample stream, comprising:
 calculating a first output of a one way function, using a seed and consecutive digital samples defining a first window of digital samples of a digital sample stream;   wherein said one way function provides an output having a one way function output specified number of bits;   iteratively calculating, using a computer comprising an integrated circuit, outputs of said one way function, using as inputs to said one way function, the previous output of said one way function and consecutive digital samples defining a subsequent window of digital samples of said digital sample stream, to define a first particular one way function output;   wherein said first window and each one of the subsequent windows are distinct from one another, and wherein said first window and said subsequent windows define a first portion of said digital sample stream;   encoding a digital message and said first particular one way function output into said first portion of said digital sample stream.   
     
     
         27 . The method of  claim 26  wherein said one way function is insensitive to changes in said first portion of said digital sample stream induced by said encoding, 
     
     
         28 . The method of  claim 27  wherein said encoding encodes in least significant bits, and said one way hash function is not a function of least significant bits. 
     
     
         29 . The method of  claim 26  wherein said one way function is a hash function. 
     
     
         30 . The method of  claim 26  where said one way function outputs a check sum. 
     
     
         31 . The method of  claim 26  wherein said one way function is a digital signature. 
     
     
         32 . The method of  claim 26  further comprising encrypting said digital message and said first particular one way function output prior to said encoding. 
     
     
         33 . The method of  claim 26  wherein said encoding comprises encoding a portion of said digital message into each one of said first window and the subsequent windows of said first portion. 
     
     
         34 . The method of  claim 26  wherein said first portion has a size that said encoding uses to encode said digital message in said digital sample stream. 
     
     
         35 . The method of  claim 26  wherein said encoding is a stega-cipher encoding. 
     
     
         36 . A computer implemented method for encoding a digital sample stream, comprising:
 encoding a first portion of said digital sample stream with a digital message and an output of a one way function, wherein said one way function is insensitive to said encoding such that said output of said one way function is unaffected by the presence or absence of said digital message.   
     
     
         37 . The method of  claim 36  wherein said one way function is insensitive to least significant bits in said digital sample stream and said encoding encodes least significant bits. 
     
     
         38 . The method of  claim 36  where said one way function is a function applied sequentially to distinct windows of said first portion. 
     
     
         39 . The method of  claim 41  wherein said one way function is a hash function. 
     
     
         40 . The method of  claim 41  wherein an output of said one way function is a check sum. 
     
     
         41 . The method of  claim 41  wherein said one way function is a digital signature. 
     
     
         42 . The method of  claim 41  further comprising encrypting said digital message and said output of said one way function prior to said encoding. 
     
     
         43 . The method of  claim 41  wherein said encoding is a stega-cipher encoding.