词条 | Device Keys | ||||||||
释义 |
Device Keys play a role in the cryptographic key management procedure in the Advanced Access Content System (AACS) specification. This specification defines a method for protecting audiovisual entertainment content, including high-definition content. IntroductionThe AACS’s cryptographic key management procedure uses Device Keys to decrypt one or more elements of a Media Key Block (MKB), in order to extract a secret Media Key (Km). A MKB is located on the physical support (the disc) together with the content of the disc encrypted. MKB enables system renewability. The MKB is generated by AACS LA, and allows all compliant devices, each using their set of secret Device Keys, to calculate the same Media Key (Km).
How it worksEach compliant device is given a set of secret Device Keys when manufactured. The actual number of keys may be different in different media types. These Device Keys, referred to as Kdi (i=0,1,…,n-1), are provided by AACS LA. The set of Device Keys may either be unique per device, or used commonly by multiple devices. A device shall treat its Device Keys as highly confidential. The MKB is encrypted in a subset difference tree approach. In order to decrypt it, a device must know the right Processing Key (P) which is available via the subset-difference tree process. This way, to revoke a given device key, the MKB needs only be encrypted with a Processing Key which is not reachable by its Device Keys set. StoringEach device is given its Device Keys and a 31-bit number d called the device number. For each Device Key, there is an associated number denoted the path number, the “u” bit mask, and the “v” bit mask. The device number, path number, and masks denote nodes within a binary tree. Sources
See also
External links
1 : Advanced Access Content System |
||||||||
随便看 |
|
开放百科全书收录14589846条英语、德语、日语等多语种百科知识,基本涵盖了大多数领域的百科知识,是一部内容自由、开放的电子版国际百科全书。