Patent ID: 7930558
Filing Date: 2011-04-19
Classification: G06F,G06Q,G07F

Abstract:
1. A data storage device for shifting specific data allowed to exist uniquely to a different data storage device, comprising: a history information holding unit holding first history information for specifying processing of shifting said specific data to said different data storage device; a storing unit for storing encrypted content data; a specific data holding unit holding said specific data and an output enable/disable flag indicating whether a part or a whole of said specific data can be externally output or not; and a control unit, wherein said control unit, in response to a request for shifting of said specific data, sets said output enable/disable flag to disable the output of said specific data and then shifts said specific data to said different storage device, when said output enable/disable flag is set to enable the output of said specific data; said control unit, in response to a request for shifting of said specific data, does not shift said specific data to said different storage device and does not change said output enable/disable flag, when said output enable/disable flag is set to disable the output of said specific data; said control unit receives, in response to a request for restoration of said specific data, communication information representing a state of communication with said different data storage device and held in said different data storage device and second history information for specifying said shifting processing held in said different data storage device, checks the state of communication with said different data storage device based on said communication information, and determines whether said second history information matches with said first history information or not, when said communication information represents that said shifting has been discontinued before completion; said control unit sets said output enable/disable flag to enable the output of said specific data when it is determined that said second history information matches with said first history information; and said specific data is a license for decrypting the encrypted content data.