发明名称 |
Data reproduction apparatus capable of safely controlling reproduction time of encrypted content data and data reproduction circuit and data recording apparatus used for the same |
摘要 |
A decryption processing unit decrypts encrypted content data using a license key Kc. When an elapsed time after reception of the license key (Kc) does not exceed a hold time at a time of the license key (Kc) included in reproduction control information (ACp), reproduction of encrypted content data continues. When the elapsed time exceeds the hold time at a time, the license key (Kc) is discarded, and a reproduction control unit again obtains a license key (Kc) from a memory card. Discarding and reobtaining license key (Kc) continues until an allowable output count of license key (Kc) from the memory card becomes zero. As a result, a reproduction time of encrypted content data can be controlled safely.
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申请公布号 |
US7428307(B2) |
申请公布日期 |
2008.09.23 |
申请号 |
US20030482681 |
申请日期 |
2003.12.31 |
申请人 |
SANYO ELECTRIC CO., LTD.;FUJITSU LIMITED;HITACHI, LTD. |
发明人 |
HORI YOSHIHIRO;HASEBE TAKAYUKI;HIRAI TATSUYA |
分类号 |
G06F12/14;H04L9/00;G06F21/00;G06F21/24;G09C1/00;G11B20/00;H04L9/08;H04L9/10 |
主分类号 |
G06F12/14 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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