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Software protection system

  • US 4,471,163 A
  • Filed: 10/05/1981
  • Issued: 09/11/1984
  • Est. Priority Date: 10/05/1981
  • Status: Expired due to Term
First Claim
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1. A system for limiting reproduction of an electrically representable process comprising:

  • process means for storing symbols U representative of a series of operations performable by a plurality of electrical signals U'"'"';

    symbol generating and storage means for generating and storing a plurality of test symbols V representative of a go/no-go test and performable by a plurality of signals V'"'"';

    storage means responsive to said process means and said symbol generating and storage means for storing a composite W of symbols U and V;

    first translation and memory means for translating said symbols W, stored by said storage means into digitally encoded electrical signals W'"'"', including signals U'"'"' and V'"'"', representative of symbols U and V, respectively, and storing these signals;

    key generating means comprising means responsive to symbols having, in part, a common derivative to that of said test symbols V for generating key symbols K;

    second translation and memory means for translating symbols K, from said key generating means, into electrical signals K'"'"' and storing same;

    signal processing means responsive to the receipt of said signals U'"'"' for the performance of said series of operations;

    coupling means responsive to a selected input signal for coupling said signals U'"'"' from said first translation and memory means to said signal processing means; and

    a process limiting means comprising;

    correlation means including means for effecting a selected correlation between aspects of said signals V'"'"', from said first translation and memory means, and signals K'"'"', from said second translation and memory means, and for providing a correlation output signal which is a function of said correlation;

    andsignal means responsive to a selected output of said correlation means for providing an input signal to said coupling means;

    whereby, upon said selected output of said correlation means, the performance of said series of operations is enabled.

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