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Microprocessor intended particularly for executing the calculation algorithms of a public code encoding system

  • US 4,807,288 A
  • Filed: 11/30/1983
  • Issued: 02/21/1989
  • Est. Priority Date: 11/30/1982
  • Status: Expired due to Term
First Claim
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1. A one chip microprocessor for executing a public key algorithm of a public code encoding system formed by a public function and a secret inverse function of the type comprising at least one programmable read-only memory, a processing unit and an input/output device, wherein it comprises a memory, in which is recorded at least one algorithm corresponding to the performance of said secret function, and wherein the programmable read-only memory contains the secret parameters constituting the secret code and recorded in an area of the read-only memory which is inaccessible from the outside, the processing unit including multiplying circuits for the execution of the algorithm, the microprocessor further including a first address register for addressing an information to be modified into the memory and a second register for the address progression of a writing sequence authorizing the writing of the modified information of the memory, said two registers being respectively associated with two data registers.

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