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Document copying deterrent method using line and word shift techniques

  • US 5,629,770 A
  • Filed: 03/31/1995
  • Issued: 05/13/1997
  • Est. Priority Date: 12/20/1993
  • Status: Expired due to Term
First Claim
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1. A method of deterring illicit copying of electronically published documents, comprising the steps of:

  • electronically creating a plurality of copies of a document for distribution to a plurality of subscribers;

    encoding each of said plurality of copies of said document with a unique identification code, said identification code being based on a combination of line-shift coding and word-shift coding; and

    creating a codebook to correlate each such identification code to a particular one of said plurality of subscribers.

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