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Key management system for open communication environments

  • US 4,897,875 A
  • Filed: 09/03/1987
  • Issued: 01/30/1990
  • Est. Priority Date: 09/04/1986
  • Status: Expired due to Fees
First Claim
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1. A security system for authenticating a potential user of a service comprising a first unit associated with the service, a second unit associated with the user, each of said first and second units including means for communicating with the other through a communication medium, each of said first and second units including memory means, each of said memory means having stored therein a plurality of groups of random numbers, the numbers of each group being logically associated together as a group with a logical address in the memory, said random numbers of said groups and the associated addresses in the memory means of the first unit being identical to those of the memory means of the second unit, said first unit including control circuit means arranged such that, in a first cycle of operation said circuit means acts, to extract from the memory means thereof one of the random numbers in one of said groups at a respective address to communicate said one random number to said second unit, to compare a received signal from the second unit with another of the random numbers in said one of said groups, and to provide authentication of said user only upon a match of said received signal with said another of the random numbers, and in each subsequent cycle of operation to extract one of the random numbers from a respective different one of the groups in the memory means, said second unit including control circuit means arranged such that it acts on receipt from said first unit of said one of the random numbers in said one of said groups to extract from said memory means thereof said another of said random numbers of said group.

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