发明名称 Hierarchical encryption key system for securing digital media
摘要 The hierarchical encryption key system uses multiple encryption processes for encrypting digital media content in a manner that supports both broadcast and delayed or time-shifted modes of content delivery. The hierarchical encryption key system uses a hierarchical series of encryption keys wherein each subsequent key in the hierarchy encrypts successively increasing time periods of the content that is transmitted from the Cable Modem Termination System to the consumer device. In addition, at one of the layers, the keys are aggregated into a collection or table of keys. The aggregation of keys facilitates the playback of recorded digital content (as opposed to broadcast or streaming digital content) by aggregating keys required for the duration of the content separately. The different layers are linked in a manner to make it difficult to use a brute force attack in an attempt to determine the keys.
申请公布号 US7480385(B2) 申请公布日期 2009.01.20
申请号 US20040982994 申请日期 2004.11.05
申请人 CABLE TELEVISION LABORATORIES, INC. 发明人 WEBER JOSEPH W.
分类号 H04L9/16 主分类号 H04L9/16
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