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Block-cipher cryptographic device based upon a pseudorandom nonlinear sequence generator

  • US 5,054,067 A
  • Filed: 02/21/1990
  • Issued: 10/01/1991
  • Est. Priority Date: 02/21/1990
  • Status: Expired due to Term
First Claim
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1. A block-cipher cryptographic device for processing plain-text or encrypted input data with a key signal to provide encrypted or decrypted output data respectively, comprisinga shift register for receiving the input data;

  • anddata processing means, including a pseudorandom nonlinear sequence generator, for executing a data processing routine for a selected number of cycles to provide the output data, wherein the data processing routine includes;

    processing the contents of said shift register with a key signal to provide initially processed data;

    initializing the pseudorandom nonlinear sequence generator with the initially processed data;

    running the pseudorandom nonlinear sequence generator to generate a keystream;

    segregating portions of the keystream;

    processing said segregated portions of said keystream with a portion of the data in the shift register to provide a block of processed data; and

    shifting said block of processed data into the shift register.

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