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Data file authentication device

  • US 6,167,516 A
  • Filed: 11/25/1997
  • Issued: 12/26/2000
  • Est. Priority Date: 04/12/1996
  • Status: Expired due to Fees
First Claim
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1. A device for authenticating a data file, comprising:

  • an input (2) capable of receiving the data of a file to be processed;

    a buffer memory (3) arranged to store said data in the form of blocks, at predetermined addresses;

    a pseudorandom module (4) provided with a working memory (MT) having at least a first segment (SS), a second segment (RI), and a third segment (AI);

    a source memory (MS) of the read-write memory type, capable of storing words, each accompanied by an extraction status; and

    processing means (5) arranged to cooperate with the pseudorandom module (4) and the source memory (MS) so as to authenticate the file, said processing means being arranged for performing;

    a first transfrinnation on a word extracted from the source memory (MS) at an address drawn from the first segment (SS(i)), anda second transformation on the third segment (AI), with an operand which is either one of said data blocks or, if there are no longer any, the extracted word from the source memory (MS), the extraction statis of said extracted word being then modified,wherein the processing means includes;

    an initializing module (6) to initialize the pseudorandom module,transfer means (7) capable of placing into the second segment (RI(i+4)), the transform by said first transformation of the extracted word, and finally replacing the extracted word in the source memory, by the transform by said second transformation of the third segment (AI),a cyclic logic (8) for actuating the pseudorandom module (4), and causing the transfer means (7) to operate until all the words of the source memory (MS) have been extracted once, and once only, anda generator (9) of the authentication sequence, capable of actuating the pseudorandom module (4), and extracting a random bit from one of the first segment (SS) and second segment (RI) at an address drawn from the third segment (AI), repetitively until a predetermined number of random bits is obtained, andwherein said predetermined number of random bits forms an authentication sequence for authenticating the data file.

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