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Server apparatus, communication system, and data issuing method

  • US 10,069,815 B2
  • Filed: 06/11/2014
  • Issued: 09/04/2018
  • Est. Priority Date: 06/12/2013
  • Status: Expired due to Fees
First Claim
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1. A server apparatus comprising:

  • processing circuitry configured tocommunicate with a plurality of devices in a wireless network;

    issue data to the devices, respectively; and

    transmit the issued data to the devices, respectively; and

    hardware storage configured to store a data set including the data issued to the devices, a filter having a predetermined bit length, and a revoked data set comprising a set of pieces of invalidated data, whereinthe processing circuitry is further configured to;

    detect whether data satisfying a certain condition exists in the data set according to a revocation request, invalidate the data satisfying the certain condition, and add the invalidated data into the revoked data set in the hardware storage;

    update the filter in the hardware storage each time invalidated data is added to the revoked data set, by setting first values to bits onto which the revoked data set including the invalidated data is projected in the filter according to a definitive projection relation and setting second values to bits different from the projected bits in the filter, and transmit the updated filter to the devices via the wireless network;

    identify, from the data set in the hardware storage, reissuance target data other than the invalidated data, the reissuance target data having projection onto at least one of bits whose bit value has changed from the second value to the first value between before and after the update of the filter, and having the first values for all of bits onto which the reissuance target data is projected in the updated filter; and

    reissue, for the device having the reissuance target data, data having the second value for at least one of bits onto which the reissued data is projected in the updated filter, and transmit reissued data to the device via the wireless network, whereinthe processing circuitry is configured to discard, in a case in which a number of pieces of data having projection onto a bit onto which the issued data is projected in the filter reaches an upper limit in the data set, the issued data, and repetitively issue data until data having projection onto a bit for which the upper limit is not reached is issued.

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