In Digital Video Broadcasting, the
Common Interface (also called
DVB-CI) is a technology which allows decryption of pay TV channels.
Pay TV stations want to choose which encryption method to use. The
Common Interface allows TV manufacturers to support many different pay
TV stations, by allowing to plug in exchangeable CAM modules for
various encryption schemes.
Common Interface is the connection between the TV tuner (TV or
set-top box) and the module (CAM) that decrypts the TV signal. The CAM
module, in turn, then accepts the pay-to-view subscriber card, which
contains the access keys and permissions.
The host (TV or set-top box) is responsible for tuning to pay TV
channels and demodulation of the RF signal, while CAM is responsible
for CA descrambling. The
Common Interface allows them to communicate
with each other. All
Common Interface equipment must comply with the
EN 50221-1997 standard. This is a defined standard that enables the
addition of a conditional-access module (CAM) in a
DTV receiver to
adapt it to different kinds of cryptography. The EN 50221
specification allows many types of modules but only the
conditional-access module (CAM) has found popularity because of the
pay TV market. Indeed, one of Digital Video Broadcasting's main
strengths is the option of implementing the required conditional
access capability on the Common Interface.
This allows broadcasters to use modules containing solutions from
different suppliers, thus increasing their choice of anti-piracy
1 Mode of operation
Conditional-access module (CAM)
2.1.1 Transport Stream Interface (TSI)
2.1.2 Command Interface
18.104.22.168 Initial versions
22.214.171.124 CI+ v1.3
126.96.36.199 CI+ v1.4
188.8.131.52 CI+ v2.0
184.108.40.206 Content protection
220.127.116.11 Enhanced MMI
2.2.4 Operators (partial list)
2.3 Compatible TV sets (partial list)
3 Embedded Common Interface
4 See also
6 External links
Mode of operation
A DVB receiver may have one or two slots implementing the Common
Interface (CI). The CI uses the conditional-access module (PCMCIA)
connector and conforms to the
Common Scrambling Algorithm
Common Scrambling Algorithm (CSA), the
normative that specifies that such a receiver must be able to accept
Encryption Standard) keys in intervals of some milliseconds,
and use them to decode private channels according to a specific
Those algorithms are proprietary to individual suppliers. Each one
uses their own algorithms and there is no defined standard for them.
As the full
MPEG-2 transport data stream comes out of the demodulator,
and error correction units, the
DTV Receiver sends it through the card
plugged into the Common Interface, before it is processed by the MPEG
demultiplexer in the receiver. If several CI cards are present, the
MPEG transport data stream will be passed sequentially through all
An embedded CAM may not physically exist, as it may be in CPU
software. In such a case, only the smart card reader normally in the
CAM is fitted and not the
PCMCIA type CI slots.
Even if the
Common Interface has been created to resolve cryptography
issues, it can have other functions using other types of modules such
as Web Browser, iDTV (Interactive Television), and so forth.
In Europe, DVB-CI is obligatory in all iDTV terminals.
Conditional-access module (CAM)
Main article: Conditional-access module
The host sends an encrypted
MPEG transport stream
MPEG transport stream to the CAM and the
CAM sends the decrypted transport stream back to the host. The CAM
often contains a smart-card reader.
The normative DVB-CI standard EN 50221 was defined in 1997 by CENELEC,
the European Committee for Electrotechnical Standardization.
According to the
Common Interface scheme:
host : A device where module(s) can be connected; for example, an
Integrated receiver/decoder (IRD), a VCR, a PC ...
module : A small device, not working by itself, designed to run
specialized tasks in association with a host; for example, a
conditional access sub system, an electronic program guide application
module, or to provide resources required by an application but not
provided directly by the host.
The specification only defines two aspects, two logical interfaces to
be included on the same physical interface. The first interface is the
MPEG-2 Transport Stream. The link and physical layers are defined in
this specification and the higher layers are defined in the MPEG-2
specifications. The second interface, the command interface, carries
commands between the host (receiver) and the module.
The specification does not define the operation or functionality of a
conditional access system application on the module. The applications
that may be performed by a module communicating across the interface
are not limited to conditional access or to those described in this
specification. More than one module may be supported concurrently.
The common interface shares many features of the
PC Card Standard
(PCMCIA). By reducing the widths of the address and data busses it has
been possible to include a bi-directional parallel transport stream
Transport Stream Interface (TSI)
The transport stream format is specified by IEC 13818-1 and is the
MPEG 2 TS format.
In addition there is a command interface for communication between the
host and module.
This communication is in the form of a layered protocol stack which
allows the host and module to share resources. For example, the module
can request the current date and time from the host. To use this
service, module shall open a session to the "Date-Time" resource
provided by host. Or, module can ask the host to display a message on
the TV screen and can then read keypresses from the host remote
control. This is done by opening a session to host's Man-Machine
Interface (MMI) Resource. This resource also allows the CAM to request
and receive PIN numbers.
Some of defined by DVB-CI resources are de facto optional. For
example, the host could contain a modem for communication over a
telephone line allowing the CAM to implement pay-per-view. This can be
done by opening a session to host's Low-Speed Communication (LSC)
resource (assuming that the host announced the availability of this
resource). The Host Control resource (allowing CAM to request
force-tuned) also may be absent in some of hosts.
The definitely mandatory resources are Resource Manager, Application
Conditional Access Support ones. First two of these
three are necessary for initial handshaking between CAM and its Host,
while the CA Support resource is necessary for descrambling the
The Command Interface is extensible and there are several
specification documents available which describe these extensions
ETSI TS 101 699). However these extensions have often not proved
popular with manufacturers.
CI+ (also known as CI Plus or
Common Interface Plus) is a
specification that extends the original DVB
Common Interface standard
(DVB-CI, v1). The main addition introduced by CI+ is a form of copy
protection between a CI+ conditional-access module (referenced by the
spec as CICAM, while CI+ CAM seems to be a more precise abbreviation)
and the television receiver (Host). CI+ is backward compatible with
DVB-CIv1. Old television receivers, which have CIv1 CI-slot, can be
used with CI+ CAM and vice versa, but for viewing only those of TV
programs which are not marked as CI+ protected.
CI+ specification has been developed by consumer electronic firms
Panasonic, Philips, Samsung and Sony, as well as pay-TV technology
company SmarDTV and fabless chip maker Neotion.
A first draft of the specification was put up for review in January
2008 as V1.00 CI Plus Specification. The establishment of the Trusted
Authority has been completed and an official security certification
In 2009, versions 1.1 and 1.2 were released. The 1.2 version became
the first one which was massively deployed. The main features added to
the original DVB-CI standard by the CI+ V1.2 are:
Content Control (allows re-encryption of video and audio on their way
from CI+ CAM to its host)
coordination of CAM firmware upgrade between CAM and its host
"CI Plus browser" - support of
MHEG-5 applications running on a CI+
host, launched by a CI+ CAM and being able to communicate with it
support of IP communication was added to the DVB-CI's Low-Speed
Communication (LSC) resource (but without renaming it to
The spec doesn't state explicitly about each feature if it is
mandatory or optional. The mandatory feature (as it's actually the
main raison d'être of CI+) is Content Control. The optional feature
of V1.2 version is "PVR Resource" – this can be concluded from the
fact that it doesn't appear in newer CI+ spec versions.
In 2011, version 1.3.1 was released. The main features added by CI+
V1.3.1 to CI+ V1.2 are:
various enhancements of Content Control mechanism
coordination of parental control PIN code handling between CAM and its
better IP communication support (increased data throughput)
a new Operator Profile resource allowing CAM to adapt non-standard
broadcast-specific service information to standard DVB format
understandable by Host.
With the development of CI+, the standard has now come under the
umbrella of the DVB standards organization.
In 2014, DVB released
ETSI TS 103 205 V1.1.1 specification, defining
what is often referred as "CI+ v1.4". The main features added by ETSI
TS 103 205 V1.1.1 to CI+ v1.3.1 are:
URI (usage rules information) extensions (the most prominent is
addition of trick mode enable/disable flag)
IP-delivered video support
watermarking and transcoding capability
the communication functionality was extended to support IP multicast
and hybrid type of communication (hybrid communication means here that
IP multicast data arrive to module over the transport stream
CI Plus™ browser extensions (interaction channel, streaming, video
letting a CI+ CAM to determine if its Host supports an advanced
application environment (e.g.
HbbTV or MHP) and, if yes, to launch a
allowing CI+ CAM applications to be represented in the Host's channel
line-up in form of virtual channels.
DVB standards organization announced working on version 2.0 of the
DVB CI+ specifications. The main evolution of this version is to add
USB as physical layer to replace the aging
PC Card interface.
CI+ Host and CAM testing and certification is carried out by Eurofins
Digital Testing (formerly Digital TV Labs) in Belgium, the UK and Hong
By making use of certificates issued by a trusted certification
authority, a secure authenticated channel (SAC) is formed between a
CI+ CAM and television receiver (Host). This SAC is used to generate a
shared key, unique per a CAM-Host pair, which protects from
unauthorized copying the content marked in the associated URI (Usage
Rules Info) as a content which needs to be re-encrypted on its way
from CAM to Host after removal the original CA or DRM scrambling (in
the original CI standard, decrypted content could be sent over the
PCMCIA interface only in unscrambled form).
CI+ standard allows revocation of compromised CI+ Hosts. This is done
by broadcasting a Service Operator Certificate Revocation List (SOCRL)
DSM-CC data carousel. If CAM detects that its Host's ID, model or
brand is listed in SOCRL (and isn't listed in optional SOCWL - Service
Operator Certificate White List), the CAM must refuse descrambling the
content marked in CI+ URI as protected. A SOCRL is created and signed
by the CI+ Root-of-Trust on request of a Service Operator. To prevent
replay of out-of-dated SOCRL and SOCWL, they must be broadcast in
combination with RSD (Revocation Signaling Data) table which specifies
the last versions of SOCRL and SOCWL and their location in the DSM-CC
data carousel. The RSD also must be signed.
A CI+ compliant Host device must also implement
MHEG-5 interactive TV
engine to manage navigation of the user within an interactive TV
application, using its device remote control. Support of MHP or
HbbTV interactive TV engines is optional.
Operators (partial list)
The following operators have currently rolled out CI+ support or plan
to do so:
Blizoo - launched CI+ in 2014
Telenet – launched CI+ in June 2013
VOO - launched CI+ in September 2015
evotv - launched CI+ v1.3
Canal+ – launched the "Canal Ready" label for devices able to
Mediaset Premium (Digital terrestrial television) - needs CI+ slot on
HD television to descramble High Definition channel Premium Calcio HD.
Caiway – launched CI+ in October 2009
Delta NV – launched CI+ in 2010
Kabel Noord – launched CI+ in 2010
Ziggo – launched CI+ in September 2009 (2011 in former UPC areas),
SMiT and Neotion CAM modules are used
Romania - launched CI+ in April 2012
RCS & RDS - Starting November 2013
UPC Cablecom – Starting June 2010
Top Up TV
In July 2009 the largest Cable operator in the Netherlands, Ziggo,
announced that it will support CI+ based Integrated Digital Television
sets (IDTVs) actively. In September 2009 the first batch
of 15,000 SMiT (Shenzhen State Micro Technology Co., Ltd.) CI+ CAMs
was offered by various Dutch retailers, followed in October 2009 by
the first batch of Neotion CAMs. Other supporters include
Canal+, and conditional access companies Irdeto and Conax.
In 2009, NDS (now Cisco) announced that it will support Kabel
Deutschland to deploy CI+ to its customers. In 2014, CI+ CAMs with
VideoGuard CA, manufactured by SMiT were deployed at D-Smart,
KDG (Kabel Deutschland), KBW, Sky Deutschland,
Tele Columbus etc.
Compatible TV sets (partial list)
LG 2010 models all LD and LE series also MFT models MXX80D.
Many of Samsung's new LCD, LCD LED and Plasma model variants with CI+
compatible motherboards, although there were some incompatibilities
between TV and UPC and RCS-RDS CI+ modules, even with models certified
by UPC and RCS-RDS. Some problems were solved by upgrading the
firmware of the TV, other were solved by simply replacing ( in many
cases under warranty ) the motherboard.
Many of Sony's new models including the Bravia W5500 series. Some
older models needed a firmware update.
Philips new 5000 and 9000 series LCD TVs (required firmware pending
according to Ziggo).
Panasonic early models (until early 2011) with CI+ slots needed a new
firmware to be fully CI+ compatible. (Update 2010). All
incompatibility problems were solved by software and firmware updates,
or sometimes by using a CI+ card or module with other firmware. All
models produced after early 2011 are fully compatible with CI+.
Tesco Technika models.
Vestel based TV sets. Newer
Vestel based TV sets are marking the
fact they are CI+ certified in their SHOP MODE ( or DEMO MODE ), which
is mentioning, beside other features, the CI+ compatibility ( no
matter DVB-T, DVB-C, DVB-S), or simply by a sticker attached on the
front of the set. Sometimes, however in many cases, CI+ compatibility
Vestel sets is mentioned on the package, beside other main
Embedded Common Interface
ETSI working group will be working on Embedded Common Interface
Conditional-access module (CAM)
^ "Cabot Communications Ltd. CI+ Technical Paper". Archived from the
original on 2012-03-08. Retrieved 2013-07-10.
^ "Führende TV-Hersteller vertrauen bei der Umsetzung des CI
Plus-Standards in Europa auf TC TrustCenter (German)" (PDF). Archived
from the original (PDF) on 2009-04-24. Retrieved 2013-07-10.
^ 10.48 Europe/London (2009-03-05). "Digital TV Labs to test for CI
Plus". Broadbandtvnews.com. Retrieved 2013-07-10.
^ 10.55 Europe/London (2011-02-18). "CI Plus back with the DVB".
Broadbandtvnews.com. Retrieved 2013-07-10.
^ "DVB CIplus 2.0 on its way". DVB World. Retrieved 21 January
^ "CI PlusSpecification 1.3.1" (PDF). Retrieved 2014-08-28.
^ Caiway CI+ CAM (Dutch) Archived July 24, 2011, at the Wayback
^ 08.54 Europe/London (2009-10-16). "Caiway introduces CI Plus
modules". Broadbandtvnews.com. Retrieved 2013-07-10.
^ "Digitale Televisie Module (Dutch)". Ziggo.nl. 1970-01-01. Retrieved
^ Cablecom makes access to digital TV in HD quality and Internet
easier and cheaper
^ "CI+ Landing". Top Up TV. 2012-07-31. Retrieved 2013-07-10.
Ziggo claims “world first” with CI Plus (visited July 7th 2009)
Ziggo Approved SMiT CI+ CAM[dead link]
^ After initial pioneering, ZIGGO and NEOTION are now further
unleashing CI Plus momentum in the Digital Pay TV ecosystem[permanent
^ 13.31 Europe/London (2009-08-30). "
Ziggo starts supply of CI Plus
CAMs". Broadbandtvnews.com. Retrieved 2013-07-10.
^ 18.06 Europe/London (2009-04-27). "
Canal+ backs CI Plus with 'Canal
Ready' label". Broadbandtvnews.com. Retrieved 2013-07-10.
^ "Iredeto press release". Irdeto.com. Archived from the original on
2012-06-30. Retrieved 2013-07-10.
^ 11.28 Europe/London (2008-09-12). "
Conax announces CI+ support".
Broadbandtvnews.com. Retrieved 2013-07-10.
^ 08.45 Europe/London (2009-09-13). "NDS to deliver CI+ to KDG".
Broadbandtvnews.com. Retrieved 2013-07-10.
LinuxTV entry for common interface
EN 50221 Specification
ETSI TS 101 699 - DVB Extensions to the
Common Interface Specification
R206-001:1998 - Guidelines for Implementation and Use of the Common
Interface for DVB Decoder Applications
Gerard O'Driscoll, The essential Guide to Digital Set-Boxes and
Interactive TV, reprinted April 2000
Jerry whitaker, Television Receivers, 2001
CI Plus official web site
CI Plus Specification V1.2 (2009-04)
CI Plus Specification V1.3.1 (2011-09)
ETSI TS 103 205 V1.1.1 (aka CI+ V1.4)
Official CI Plus TrustCenter
Official CI Plus test lab
Open source and open hardware CI implementation (Joker TV)
Broadcast encryption and digital rights management
Conditional access system
Smart cards and encryption
Digital video disc
Content Scramble System (CSS)
Advanced Access Content System
Advanced Access Content System (AACS)
Analogue broadcast encoding
See also free-to-view