DVB-CPCM
Encyclopedia
DVB Content Protection & Copy Management often abbreviated to DVB-CPCM or CPCM is a digital rights management
standard being developed by the DVB Project. Its main application is interoperable rights management of European digital television
, though other countries may also adopt the standard.
Content providers can use a range of flags stored with the content to describe how it may be used. All CPCM-enabled devices should obey these flags. These flags can allow or deny content to be either moved or copied to other CPCM devices. Content may also be provided for a set time limit, or forbid content to be played concurrently on separate devices.
" of devices. The authorized domain can include devices both in the home or in remote locations such as cars or vacation homes. It also specifies whether content should remain inside the home (the "local environment") or inside a physical region, such as a country (the "geographic area").
Unlike most DRM systems, CPCM (in theory) supports a choice of robustness regimes rather than tying everyone to a single set of conditions. It is possible that different regimes may emerge e.g. distinct trust models for pay TV, free TV, or even public domain
type content. Each of these could have appropriate levels of robustness requirement. It would even be possible to define a CPCM C&R regime that permits implementation in user-modifiable software, though this would probably not be trusted to receive content from most commercial services.
That said, at this time no regime has been announced, so any restrictions have yet to be identified
.
CPCM is only applied in the home after the broadcast has been received, never added to a broadcast signal.
The DVB has now defined signals within the DVB Service Information (DVB-SI) which allow a free-to-air broadcaster to signal correct behaviour for content protection systems such as CPCM. These signals are not specific to use with CPCM, and can also be used to control HDCP
or similar systems. However, CPCM does defined an exact mapping of these SI signals to the CPCM usage state information. See http://www.dvb.org/technology/dvb-cpcm for further information.
It is worth noting that Europe does not have a single regulating authority like the FCC, so an exact parallel to the enforcement rules of the failed US approach is unlikely.
protects a single wire connection, typically DVI
or HDMI
. CPCM is network independent and can be used on LAN, WiFi, and in theory even on IEEE 1394 Firewire links.
DTCP-IP is a link protection system similar to HDCP, but operates over a LAN or WLAN connection.
Both HDCP and DTCP-IP are link protection "render and toss" technologies that generally prohibit the receiving device from recording or redistributing the content. Also, both are designed to prevent connection of devices that are not in close proximity to one another. CPCM by contrast can allow for recording and/or remote access depending on the specific rights granted with the content.
The normative sections have now all been approved for publication by the DVB Steering Board, and will be published by ETSI
as a formal European Standard as ETSI TS 102 825-X where X refers to the Part number of specification.
Nobody has yet stepped forward to provide a Compliance and Robustness
regime for the standard (though several are rumoured to be in development), so it is not presently possible to fully implement a system, as there is nowhere to obtain the necessary device certificates.
Digital rights management
Digital rights management is a class of access control technologies that are used by hardware manufacturers, publishers, copyright holders and individuals with the intent to limit the use of digital content and devices after sale. DRM is any technology that inhibits uses of digital content that...
standard being developed by the DVB Project. Its main application is interoperable rights management of European digital television
Digital television
Digital television is the transmission of audio and video by digital signals, in contrast to the analog signals used by analog TV...
, though other countries may also adopt the standard.
How it works
CPCM specifies a way of adding information to digital content, such as television programs, to describe how and if content may be used and shared among other CPCM-enabled devices.Content providers can use a range of flags stored with the content to describe how it may be used. All CPCM-enabled devices should obey these flags. These flags can allow or deny content to be either moved or copied to other CPCM devices. Content may also be provided for a set time limit, or forbid content to be played concurrently on separate devices.
Domains
CPCM can distinguish between devices inside and outside an "authorized domainAuthorized domain
In the DVB Project's Content Protection and Copy Management scheme, an Authorized Domain is a set of CPCM-compliant devices that "are owned, rented or otherwise controlled by members of a single household", according to the DVB Project. Industry observers saw Authorized Domain as having the...
" of devices. The authorized domain can include devices both in the home or in remote locations such as cars or vacation homes. It also specifies whether content should remain inside the home (the "local environment") or inside a physical region, such as a country (the "geographic area").
Robustness requirement
CPCM (as do all content protection mechanisms used for pay TV) contains a "robustness requirement" that demands that manufacturers design their technologies to resist end-user modification, which makes it impossible to implement a fully trusted CPCM in user-modifiable software like Linux.Unlike most DRM systems, CPCM (in theory) supports a choice of robustness regimes rather than tying everyone to a single set of conditions. It is possible that different regimes may emerge e.g. distinct trust models for pay TV, free TV, or even public domain
Public domain
Works are in the public domain if the intellectual property rights have expired, if the intellectual property rights are forfeited, or if they are not covered by intellectual property rights at all...
type content. Each of these could have appropriate levels of robustness requirement. It would even be possible to define a CPCM C&R regime that permits implementation in user-modifiable software, though this would probably not be trusted to receive content from most commercial services.
That said, at this time no regime has been announced, so any restrictions have yet to be identified
Broadcast Flag
CPCM is sometimes erroneously compared to the failed U.S. broadcast flagBroadcast flag
A broadcast flag is a set of status bits sent in the data stream of a digital television program that indicates whether or not the data stream can be recorded, or if there are any restrictions on recorded content...
.
CPCM is only applied in the home after the broadcast has been received, never added to a broadcast signal.
The DVB has now defined signals within the DVB Service Information (DVB-SI) which allow a free-to-air broadcaster to signal correct behaviour for content protection systems such as CPCM. These signals are not specific to use with CPCM, and can also be used to control HDCP
High-Bandwidth Digital Content Protection
High-bandwidth Digital Content Protection is a form of digital copy protection developed by Intel Corporation to prevent copying of digital audio and video content as it travels across connections...
or similar systems. However, CPCM does defined an exact mapping of these SI signals to the CPCM usage state information. See http://www.dvb.org/technology/dvb-cpcm for further information.
It is worth noting that Europe does not have a single regulating authority like the FCC, so an exact parallel to the enforcement rules of the failed US approach is unlikely.
HDCP and DTCP-IP
HDCPHigh-Bandwidth Digital Content Protection
High-bandwidth Digital Content Protection is a form of digital copy protection developed by Intel Corporation to prevent copying of digital audio and video content as it travels across connections...
protects a single wire connection, typically DVI
Digital Visual Interface
The Digital Visual Interface is a video interface standard covering the transmission of video between a source device and a display device. The DVI standard has achieved widespread acceptance in the PC industry, both in desktop PCs and monitors...
or HDMI
High-Definition Multimedia Interface
HDMI is a compact audio/video interface for transmitting uncompressed digital data. It is a digital alternative to consumer analog standards, such as radio frequency coaxial cable, composite video, S-Video, SCART, component video, D-Terminal, or VGA...
. CPCM is network independent and can be used on LAN, WiFi, and in theory even on IEEE 1394 Firewire links.
DTCP-IP is a link protection system similar to HDCP, but operates over a LAN or WLAN connection.
Both HDCP and DTCP-IP are link protection "render and toss" technologies that generally prohibit the receiving device from recording or redistributing the content. Also, both are designed to prevent connection of devices that are not in close proximity to one another. CPCM by contrast can allow for recording and/or remote access depending on the specific rights granted with the content.
Publication
The full technical specification of DVB-CPCM is now published by the DVB Project and can be freely downloaded from this location.The normative sections have now all been approved for publication by the DVB Steering Board, and will be published by ETSI
European Telecommunications Standards Institute
The European Telecommunications Standards Institute is an independent, non-profit, standardization organization in the telecommunications industry in Europe, with worldwide projection...
as a formal European Standard as ETSI TS 102 825-X where X refers to the Part number of specification.
Nobody has yet stepped forward to provide a Compliance and Robustness
Compliance and Robustness
Compliance and Robustness, sometimes abbreviated as C&R, refers to the legal structure or regime underlying a Digital Rights Management system. In many cases, the C&R regime for a given DRM is provided by the same company that sells the DRM solution...
regime for the standard (though several are rumoured to be in development), so it is not presently possible to fully implement a system, as there is nowhere to obtain the necessary device certificates.
External links
Current standard (Official sites)- DVB Project and CPCM Specifications
- Electronic Frontier FoundationElectronic Frontier FoundationThe Electronic Frontier Foundation is an international non-profit digital rights advocacy and legal organization based in the United States...
- Fastcom Technology Fastcom Technology showed at the 50th DVB-CPT meeting (7-9 February 2007) the first demonstrator of the DVB-CPCM standard and is further developing it.