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Method for certifying the origin of at least one item of information stored in the memory of a first electronic device and transmitted to a second electronic device, and system for carrying out the method

  • US 4,549,075 A
  • Filed: 06/20/1983
  • Issued: 10/22/1985
  • Est. Priority Date: 07/08/1982
  • Status: Expired due to Term
First Claim
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1. A method for certifying the origin of at least one item of information IA stored in the memory of a first electronic device CA controlled by an individual A, said information IA, being specific to individual AM and being transmitted for certification to a second electronic device CB controlled by an individual B, said individual B being assigned at least one specific item of information IB which was previously stored into the memory MB of the second electronic device CB ;

  • comprising the steps of;

    (a) causing to be calculated within each device CA, CB a result R calculated by the same predetermined secret algorithm f and taking account of the same predetermined secret set S and the same random number EB supplied by the second electronic device CB ; and

    (b) comparing within the second device CB, the two results R, the agreement between said two results R certifying to individual B that the first device CA belongs to the same group as his device CB owing to the fact that the two devices contain the same secret set S and the same algorithm f;

    (c) information retrieval service individual certifying the origin of the information IA, causing the algorithm f to take account of a supplementary parameter J which, in turn, takes account of both items of information IA, IB, combined in accordance with the same predetermined secret algorithm p and exchanged between two devices CA, CB ; and

    (d) causing the first device CA to calculate a result R=f (EB, S, J) with J=p (IA, IB) and the second device to calculate a result R=f (EB, S, J) with J=p (IB, IA), the algorithm p being symmetrical so that J=p (IA, IB)=p (IB, IA) and thus certifying to (information retrieval service) individual B, in case of an agreement between said two results R, that the information IA has not been altered during its transfer from the first electronic device CA, and that it comes solely from said first device CA.

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