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Power saving control apparatus and method

  • US 9,787,716 B2
  • Filed: 11/12/2008
  • Issued: 10/10/2017
  • Est. Priority Date: 11/16/2007
  • Status: Active Grant
First Claim
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1. A power-saving control apparatus comprising:

  • a first memory to store first to Nth (N is a natural number not less than two) different first authentication codes;

    a second memory to store first to Mth (M is a natural number not less than two) different second authentication codes;

    a reception circuit to receive (a) a first radio operation signal including a first authentication code and a second authentication code or (b) a second radio operation signal including the first authentication code and a third radio operation signal including the second authentication code, the first authentication code being included in the first authentication codes, the second authentication code being included in the second authentication codes;

    a first determination circuit to determine, every time the reception circuit receives the first radio operation signal or both the second radio operation signals and the third radio operation signal, whether the first authentication code in the first radio operation signal or the second radio operation signal is a first valid code which matches one of the first authentication codes stored in the first memory;

    a second determination circuit to be started when the first determination circuit determines that the first authentication code in the first radio operation signal or the second radio operation signal is the first valid code, and to determine whether the second authentication code in the first radio operation signal or the third radio operation signal received is a second valid code which matches one of the second authentication codes stored in the second memory;

    an output circuit to output an operation signal to a main apparatus when the second determination circuit determines that the second authentication code in the first radio operation signal or the third radio operation signal is the second valid code;

    a first control circuit to generate a new second authentication code, every time the second determination circuit determines that the second authentication code in the first radio operation signal or the third radio operation signal received is the second valid code, to delete at least one of the second authentication codes stored in the second memory, the at least one of the second authentication codes being the second valid code, and to store the new second authentication code in the second memory;

    a counter circuit to count the number of times the first authentication code in the first radio operation signal or the second radio operation signal received matches a first one of the first authentication codes stored in the first memory; and

    a second control circuit to generate a new first authentication code, when (a) a value of the counter circuit is equal to a predetermined set value or (b) the first authentication code in the first radio operation signal or the second radio operation signal matches a second or subsequent one of the first authentication codes stored in the first memory, to delete at least one of the first authentication codes stored in the first memory, and to store the new first authentication code in the first memory,wherein when a replay attack is taken, the first determination circuit determines that the first authentication code in the first radio operation signal or the second radio operation signal received is the first valid code and the second determination circuit determines that the second authentication code in the first radio operation signal or the third radio operation signal received is an invalid code which is not included in the second authentication codes stored in the second memory.

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