发明名称 |
System for providing time dependent conditional access |
摘要 |
A source transmits ( 10 ) successive keys encrypted in encryption control messages and information in an encrypted form at is successively decryptable with the successive keys. A decoder ( 122 ) decrypts the information. A secure device ( 14 ) receives the encryption control messages, decrypts the keys from the messages and supplies the keys to the decoder ( 122 ). The secure device ( 14 ) maintains a time value. The secure device ( 14 ) controls the supply of the keys dependent on the time value, and increments the time value in response to reception of respective ones of the encryption control messages.
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申请公布号 |
US2005084106(A1) |
申请公布日期 |
2005.04.21 |
申请号 |
US20040501167 |
申请日期 |
2004.07.12 |
申请人 |
VENEMA JILLES;KAMPERMAN FRANCISCUS LUCAS ANTONIUS JOHANNES |
发明人 |
VENEMA JILLES;KAMPERMAN FRANCISCUS LUCAS ANTONIUS JOHANNES |
分类号 |
G06F21/24;G06F21/00;G06F21/62;H04L9/08;H04N1/00;H04N5/00;H04N7/16;(IPC1-7):H04N7/167 |
主分类号 |
G06F21/24 |
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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