High-Definition Audio-Video Network Alliance - Content Protection

Content Protection

HANA uses content protection developed in conjunction with IBM, a HANA member, called Advanced Secure Content Cluster Technology (ASCCT). ASCCT content protection is based on broadcast encryption key management and AES 128 for distribution and storage. ASCCT was designed specifically for home networks. Devices connected on a HANA network are cryptographically bound to each other to create an “authorized domain”, with each domain receiving its own unique ID. All devices that are members of this domain share certain cryptographic secrets allowing them to act in many ways, as if they are a single device. When content is received into the authorized domain, it too is bound in that only authorized members of the domain will have the keys to decrypt it. If a copy were to be given to a non-authorized device, it would not be able to decrypt it, rendering the copy useless. Moreover devices may only be a member of a single domain and they may only play content that is bound to that domain. This avoids any situation where a device is loaded with content on one network and then moved to another. To share content, it must join the new network at which time its keys from the original domain are destroyed and the content rendered unreadable.

ASCCT, as implemented by HANA, is a peer-to-peer solution. There is no central device that maintains the decryption keys or the library of content. Therefore there is no central failure point as there is for many other solutions such as a cable STB PVR or a PC. It is based on broadcast encryption, the same basic technology used in 4C and AACS content protection. Similar to AACS, a compromised device or class of devices is repairable by revocation of device the keys which can occur any time new content is imported into the domain, or a connection is made to a content service. Further, content can be pre-encrypted with ASCCT by provider or delivered using a proprietary content protection which is then can transcrypted to ASSCT using the built-in secure encryption engine in HANA devices.

A benefit of this approach is that it supports managed copies of content distributed by DVD, On-Demand services, downloads from the Internet, etc. Perfect copies of a movie can be stored on any or all devices within the domain without fear the copies will be distributed outside the domain. Portable devices can be disconnected and still play the content, yet if they are connected to another device or network, any copy left behind cannot be used. The decryption keys remain with the authorized device.