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Software catalog encoding method and system

  • US 5,416,840 A
  • Filed: 07/06/1993
  • Issued: 05/16/1995
  • Est. Priority Date: 07/06/1993
  • Status: Expired due to Term
First Claim
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1. A method for protecting computer program distribution within a broadcast medium that is operable on a computer using a decryption device having a unique hardware identifier j, comprising the steps of:

  • A. encrypting at least a portion of the computer program Si, the program having an associated computer program identifier i, in accordance with the formula;

    
    
    space="preserve" listing-type="equation">S.sub.i.sup.E =E(S.sub.i, SK.sub.i)wherein E is an encryption algorithm and Ski is a software encryption key;

    B. securing the software encryption key SKi against unauthorized access;

    C. generating a first table representative of correspondences between the software encryption key SKi and the computer program identifier i;

    D. generating a second table representative of correspondences between the hardware identifier j and a password key PKj ;

    E. selecting from the first and second tables the password key PKj and software encryption key SKi responsive to receipt of the hardware identifier j and computer program identifier i;

    F. generating a password Pij in accordance with the formula;

    
    
    space="preserve" listing-type="equation">P.sub.ij =F(SK.sub.i, PK.sub.j)wherein F is a reversible function; and

    G. issuing the password Pij to enable operation of the encrypted portion of the computer program.

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