发明名称 |
Key distribution in a conditional access system |
摘要 |
Methods and apparatus for key distribution in a conditional access system, assuming that the set of all user nodes which the system can accommodate is a complete set, and a subset is composed of all user nodes or part of user nodes. One method comprises: decomposing said subset into at least one secondary subset; assigning a different user key to each secondary subset, each said user key being transmitted to all users in a corresponding secondary subset; encrypting an entitlement key by using each said user key so as to generate a cipher text corresponding to each said secondary subset; and combining said cipher text to generate a media key control block and transmitting said media key control block to all users in said subset. Since a classification method of a binary tree and a multiple tree is used, the invention can save a lot of network resources.
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申请公布号 |
US2004120529(A1) |
申请公布日期 |
2004.06.24 |
申请号 |
US20030667841 |
申请日期 |
2003.09.22 |
申请人 |
INTERNATIONAL BUSINESS MACHINES CORPORATION |
发明人 |
ZHANG JIAN;LIU ZONG WEI;SHAO LING;XIE DONG |
分类号 |
H04L9/08;H04N7/16;(IPC1-7):H04L9/00 |
主分类号 |
H04L9/08 |
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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