| 摘要 |
[PROBLEMS] To provide an external memory device hardly leaking secret information even if the external memory device is lost or stolen. [MEANS FOR SOLVING PROBLEMS] An external memory device for storing information for an external information processing device. The external memory device comprises a second memory unit for storing information to the stored, an acquiring unit for carrying out conversion of the information to be stored by a secret distributing method necessary for a predetermined reference number of divided data sets to restore the information to be stored and acquiring a first number of divided data sets larger than the predetermined reference number from among the thus created divided data sets, a second storage unit for storing the first number of acquiring divided data set in the second memory unit, and a data destroying unit for destroying a number of divided data sets larger than the difference between the reference number and the first number out of the first number of stored divided data sets when a predetermined reference time passes from the time point at which a predetermined operation is given. ® KIPO & WIPO 2009
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