Title:
データ再生装置それに用いるデータ再生回路、およびデータ記録装置
Document Type and Number:
Japanese Patent JP4545994
Kind Code:
B2
Abstract:
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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Inventors:
Yoshihiro Hori
Takayuki Hasebe
Tatsuya Hirai
Takayuki Hasebe
Tatsuya Hirai
Application Number:
JP2001201000A
Publication Date:
September 15, 2010
Filing Date:
July 02, 2001
Export Citation:
Assignee:
三洋電機株式会社
富士通株式会社
株式会社日立製作所
富士通株式会社
株式会社日立製作所
International Classes:
G06F12/14; H04L9/08; G06F21/10; G06F21/44; G06F21/60; G06F21/62; G09C1/00; G11B20/00; H04L9/10; H04L9/36
Domestic Patent References:
| JP11232776A | ||||
| JP11203128A | ||||
| JP11296076A |
Other References:
山中喜義,高嶋洋一,小柳津育郎,“マルチメディアオンデマンドサービスにおける情報保護システム”,NTT R&D,日本,日本電信電話株式会社,1995年 9月10日,第44巻,第9号,p.813-818
Attorney, Agent or Firm:
Kuro Fukami
Toshio Morita
Hidehiko Ito
Yutaka Horii
Toshio Morita
Hidehiko Ito
Yutaka Horii