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Software protection device

  • US 4,634,807 A
  • Filed: 08/23/1985
  • Issued: 01/06/1987
  • Est. Priority Date: 08/23/1984
  • Status: Expired due to Fees
First Claim
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1. Apparatus for use in protecting wherein the software is independent of the operating system of a host computer comprisingfirst storage means adapted to contain at least one decryption key,second storage means containing instructions for decrypting another key using a key held in the first storage means and for decrypting encrypted software using the said other key,a processor for carrying out the instructions held by the second storage means, andswitch means having first and second modes in which the first storage means are, and are not, in communication with the processor, respectively,the switch means being constructed to enter its first mode automatically under predetermined conditions and while in this first mode to cause the processor to execute a sequence of the instructions held in the second storage means which end with an instruction which causes the switch means to enter its second mode,the first and second storage means, the processor and the switch means being contained in a tamper resistant housing, and the apparatus including an interface constructed to allow the processor to communicate with other apparatus external to the housing.

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