High-bandwidth Digital Content 
Protection System  
Interface Independent Adaptation 
Revision 2.2 
16 October, 2012 
Digital Content Protection LLC 
HDCP Interface Independent Adaptation Specification             October 16, 2012 
Revision 2.2 
 
 
 
Digital Content Protection LLC 
   
 
    
Notice 
THIS DOCUMENT IS PROVIDED "AS IS" WITH NO WARRANTIES WHATSOEVER, INCLUDING 
ANY  WARRANTY  OF  MERCHANTABILITY,  NONINFRINGEMENT,  FITNESS  FOR  ANY 
PARTICULAR  PURPOSE,  OR  ANY  WARRANTY  OTHERWISE  ARISING  OUT  OF  ANY 
PROPOSAL, SPECIFICATION OR SAMPLE. Intel Corporation disclaims all liability, including liability 
for infringement of any proprietary rights, relating to use of information in this specification. No license, 
express or implied, by estoppel or otherwise, to any intellectual property rights is granted herein. 
The cryptographic functions described in this specification may be subject to export control by the United 
States, Japanese, and/or other governments. 
Copyright  ©  1999-2011  by  Intel  Corporation.  Third-party  brands  and  names  are  the  property  of  their 
respective owners. 
Acknowledgement 
Intellectual Property 
Implementation of this specification requires a license from the Digital Content Protection LLC. 
Contact Information 
Digital Content Protection LLC 
C/O Vital Technical Marketing, Inc. 
3855 SW 153rd Drive 
Beaverton, OR 97006 
 
Email: info@digital-cp.com 
Web: www.digital-cp.com 
Revision History 
October 23, 2008  - 
2.0 Revision. Publication on DCP LLC website 
July 18, 2011 
- 
2.1 Revision. Publication on DCP LLC website 
 
 
 
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HDCP Interface Independent Adaptation Specification             October 16, 2012 
Revision 2.2 
 
 
 
Introduction .......................................................................................................... 5 
1 
Scope............................................................................................................................. 5 
1.1 
Definitions ...................................................................................................................... 5 
1.2 
Overview ........................................................................................................................ 8 
1.3 
Terminology ................................................................................................................... 9 
1.4 
References .................................................................................................................... 9 
1.5 
2  Authentication Protocol .................................................................................... 11 
Overview ...................................................................................................................... 11 
2.1 
2.2 
Authentication and Key Exchange ............................................................................. 12 
2.2.1 
Pairing .............................................................................................................................................. 17 
2.3 
2.4 
2.5 
Locality Check ............................................................................................................. 18 
Session Key Exchange ............................................................................................... 21 
Authentication with Repeaters .................................................................................... 22 
2.5.1 
2.5.2 
Upstream Propagation of Topology Information ........................................................................... 22 
Downstream Propagation of Content Stream Management Information ...................................... 28 
Link Synchronization ................................................................................................... 29 
2.6 
Key Derivation ............................................................................................................. 29 
2.7 
HDCP Transmitter State Diagram .............................................................................. 30 
2.8 
HDCP Receiver State Diagram .................................................................................. 36 
2.9 
2.10  HDCP Repeater State Diagrams ............................................................................... 37 
2.10.1 
Propagation of Topology Errors ..................................................................................................... 38 
2.10.2  HDCP Repeater Downstream State Diagram ................................................................................ 38 
2.10.3  HDCP Repeater Upstream State Diagram...................................................................................... 44 
2.11  Converters ................................................................................................................... 47 
2.11.1  HDCP 2 – HDCP 1.x Converters ................................................................................................... 47 
2.11.2  HDCP 1.x – HDCP 2 Converters ................................................................................................... 49 
2.12  Session Key Validity .................................................................................................... 51 
2.13  Random Number Generation ..................................................................................... 51 
3  HDCP Encryption ............................................................................................... 52 
Description ................................................................................................................... 52 
3.1 
AV Stream ................................................................................................................... 52 
3.2 
3.3 
Abbreviations ............................................................................................................... 53 
HDCP Cipher .............................................................................................................. 53 
3.4 
HDCP Cipher Block .................................................................................................... 55 
3.5 
3.6 
MPEG System Multiplexing ........................................................................................ 55 
3.6.1 
3.6.2 
3.6.3 
HDCP Registration Descriptor ....................................................................................................... 56 
Transport Stream ............................................................................................................................. 56 
Program Stream ............................................................................................................................... 57 
3.7 
Uniqueness of ks and riv .............................................................................................. 57 
4  Authentication Protocol Messages ................................................................. 59 
Abbreviations ............................................................................................................... 59 
4.1 
Control / Status Stream ............................................................................................... 59 
4.2 
4.3 
Message Format ......................................................................................................... 60 
4.3.1 
4.3.2 
4.3.3 
4.3.4 
4.3.5 
4.3.6 
4.3.7 
4.3.8 
AKE_Init (Transmitter to Receiver) ............................................................................................... 60 
AKE_Send_Cert (Receiver to Transmitter) ................................................................................... 60 
AKE_No_Stored_km (Transmitter to Receiver) ........................................................................... 60 
AKE_Stored_km (Transmitter to Receiver) ................................................................................... 60 
AKE_Send_rrx (Receiver to Transmitter) ...................................................................................... 61 
AKE_Send_H_prime (Receiver to Transmitter) ............................................................................ 61 
AKE_Send_Pairing_Info (Receiver to Transmitter) ...................................................................... 61 
LC_Init (Transmitter to Receiver) .................................................................................................. 61 
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4.3.9 
LC_Send_L_prime (Receiver to Transmitter) ............................................................................... 61 
4.3.10 
SKE_Send_Eks (Transmitter to Receiver) ..................................................................................... 62 
4.3.11 
RepeaterAuth_Send_ReceiverID_List (Receiver to Transmitter) ................................................. 62 
4.3.12 
RTT_Ready (Receiver to Transmitter) ........................................................................................... 63 
4.3.13 
RTT_Challenge (Transmitter to Receiver) ..................................................................................... 64 
4.3.14 
RepeaterAuth_Send_Ack (Transmitter to Receiver) ..................................................................... 64 
4.3.15 
RepeaterAuth_Stream_Manage (Transmitter to Receiver) ........................................................... 64 
4.3.16 
RepeaterAuth_Stream_Ready (Receiver to Transmitter) .............................................................. 65 
4.3.17 
Receiver_AuthStatus (Receiver to Transmitter) ............................................................................ 65 
4.3.18  AKE_Transmitter_Info (Transmitter to Receiver) ......................................................................... 65 
4.3.19  AKE_Receiver_Info (Receiver to Transmitter) ............................................................................. 66 
5  Renewability ....................................................................................................... 67 
5.1 
SRM Size and Scalability ............................................................................................ 68 
5.2 
Updating SRMs ........................................................................................................... 69 
Appendix A.  Core Functions and Confidentiality and Integrity of Values .... 71 
Appendix B.  DCP LLC Public Key ...................................................................... 74 
Appendix C.  Bibliography (Informative) ............................................................ 75 
Appendix D.  Test Vectors ................................................................................... 76 
D.1  Facsimile Keys ................................................................................................................. 76 
 
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HDCP Interface Independent Adaptation Specification             October 16, 2012 
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1 
Introduction 
 
Digital Content Protection LLC 
   
 
    
1.1  Scope 
This  specification  describes  an  interface  independent  adaptation  of  the  High-bandwidth  Digital 
Content  Protection  (HDCP)  system,  Revision  2.20.  This  specification  can  be  applied  over  any 
wired or wireless interface as explained in subsequent chapters. 
For the purpose of this specification, it is assumed that the Audiovisual content is transmitted over 
any wired or wireless display link. For example, this specification can be applied for the protection 
of Audiovisual content over an IP based wireless interface.  
In an HDCP System, two or more HDCP Devices are interconnected through an HDCP-protected 
Interface.  The Audiovisual Content flows from the Upstream Content Control Function into the 
HDCP  System  at  the  most  upstream  HDCP  Transmitter.    From  there  the  Audiovisual  Content 
encrypted  by  the  HDCP  System,  referred  to  as  HDCP  Content,  flows  through  a  tree-shaped 
topology  of  HDCP  Receivers  over  HDCP-protected  Interfaces.  This  specification  describes  a 
content  protection  mechanism  for:  (1)  authentication  of  HDCP  Receivers  to  their  immediate 
upstream  connection  (i.e.,  an  HDCP  Transmitter),  (2)  revocation  of  HDCP  Receivers  that  are 
determined by the Digital Content Protection, LLC, to be invalid, and (3) HDCP Encryption of 
Audiovisual Content over the HDCP-protected Interfaces between HDCP Transmitters and their 
downstream  HDCP  Receivers.    HDCP  Receivers  may  render  the  HDCP  Content  in  audio  and 
visual form for human consumption.  HDCP Receivers may be HDCP Repeaters that serve as 
downstream HDCP Transmitters emitting the HDCP Content further downstream to one or more 
additional HDCP Receivers. 
Unless  otherwise  specified,  the  term  “HDCP  Receiver”  is  also  used  to  refer  to  the  upstream 
HDCP-protected interface port of an HDCP Repeater. Similarly, the term “HDCP Transmitter” is 
also used to refer to the downstream HDCP-protected interface port of an HDCP Repeater 
Except  when  specified  otherwise,  HDCP  2.2-compliant  Devices  must  interoperate  with  other 
HDCP 2.2-compliant Devices, HDCP 2.1-compliant Devices and HDCP 2.0-compliant Devices 
connected to their HDCP-protected Interface Ports using the same protocol. HDCP Transmitters 
must support HDCP Repeaters. 
The state machines in this specification define the required behavior of HDCP Devices.  The link-
visible behavior of HDCP Devices implementing the specified state machines must be identical, 
even  if  implementations  differ  from  the  descriptions.  The  behavior  of  HDCP  Devices 
implementing the specified state machines must also be identical from the perspective of an entity 
outside of the HDCP System. 
Implementations  must  include  all  elements  of  the  content  protection  system  described  herein, 
unless the element is specifically identified as informative or optional. Adopters must also ensure 
that  implementations  satisfy  the  robustness  and  compliance  rules  described  in  the  technology 
license.  
Device  discovery  and  association,  and  link  setup  and  teardown,  is  outside  the  scope  of  this 
specification. 
1.2  Definitions 
The following terminology, as used throughout this specification, is defined as herein: 
Audiovisual Content.  Audiovisual works (as defined in the United States Copyright Act as in 
effect on January 1, 1978), text and graphic images, are referred to as AudioVisual Content. 
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Authorized Device.  An HDCP Device that is permitted access to HDCP Content is referred to as 
an  Authorized  Device.    An  HDCP  Transmitter  may  test  if  a  connected  HDCP  Receiver  is  an 
Authorized Device by successfully completing the following stages of the authentication protocol 
–  Authentication  and  Key  Exchange  (AKE)  and  Locality  check.  If  the  authentication  protocol 
successfully results in establishing authentication, then the other device is considered by the HDCP 
Transmitter to be an Authorized Device. 
Content  Stream.  Content  Stream  consists  of  Audiovisual  Content  received  from  an  Upstream 
Content  Control  Function  that  is  to  be  encrypted  and  Audiovisual  Content  received  from  an 
Upstream Content Control Function that is encrypted by the HDCP System. 
Device Key Set.  An HDCP Receiver has a Device Key Set, which consists of its corresponding 
Device Secret Keys along with the associated Public Key Certificate. 
Device Secret Keys.  For an HDCP Transmitter, Device Secret Key consists of the secret Global 
Constant. For an HDCP Receiver, Device Secret Keys consists of the secret Global Constant and 
the RSA private key. The Device Secret Keys are to be protected from exposure outside of the 
HDCP Device. 
downstream.  The term, downstream, is used as an adjective to refer to being towards the sink of 
the  HDCP  Content.    For  example,  when  an  HDCP  Transmitter  and  an  HDCP  Receiver  are 
connected  over  an  HDCP-protected  Interface,  the  HDCP  Receiver  can  be  referred  to  as  the 
downstream HDCP Device in this connection.  For another example, on an HDCP Repeater, the 
HDCP-protected  Interface  Port(s)  which  can  emit  HDCP  Content  can  be  referred  to  as  its 
downstream HDCP-protected Interface Port(s).  See also, upstream. 
Global Constant.  A 128-bit random, secret constant provided only to HDCP adopters and used 
during HDCP Content encryption or decryption 
HDCP 1.x.  HDCP 1.x refers to, specifically, the variant of HDCP described by Revision 1.00 
(referred to as HDCP 1.0), Revision 1.10 (referred to as HDCP 1.1), Revision 1.20 (referred to as 
HDCP  1.2)  and  Revision  1.30  (referred  to  as  HDCP  1.3)  along  with  their  associated  errata,  if 
applicable. 
HDCP  1.x-compliant  Device.  An HDCP Device that is designed in adherence to HDCP 1.x, 
defined above, is referred to as an HDCP 1.x-compliant Device. 
HDCP 2.  HDCP 2 refers to, specifically, the variant of HDCP mapping for all HDCP protected 
interfaces  described by Revision 2.00 and higher versions along with their associated errata, if 
applicable. 
HDCP 2.0.  HDCP 2.0 refers to, specifically, the variant of HDCP mapping described by Revision 
2.00 of this specification along with its associated errata, if applicable. 
HDCP 2.0-compliant Device.  An HDCP Device that is designed in adherence to HDCP 2.0 is 
referred to as an HDCP 2.0-compliant Device. 
HDCP 2.1.  HDCP 2.1 refers to, specifically, the variant of HDCP mapping described by Revision 
2.10 of this specification along with its associated errata, if applicable. 
HDCP 2.1-compliant Device.  An HDCP Device that is designed in adherence to HDCP 2.1 is 
referred to as an HDCP 2.1-compliant Device. 
HDCP 2.2.  HDCP 2.2 refers to, specifically, the variant of HDCP mapping described by Revision 
2.20 of this specification along with its associated errata, if applicable. 
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HDCP 2.2-compliant Device.  An HDCP Device that is designed in adherence to HDCP 2.2 is 
referred to as an HDCP 2.2-compliant Device. 
HDCP Content.  HDCP Content consists of Audiovisual Content that is protected by the HDCP 
System.  HDCP Content includes the Audiovisual Content in encrypted form as it is transferred 
from an HDCP Transmitter to an HDCP Receiver over an HDCP-protected Interface, as well as 
any translations of the same content, or portions thereof.  For avoidance of doubt, Audiovisual 
Content that is never encrypted by the HDCP System is not HDCP Content. 
HDCP  Device.    Any  device  that  contains  one  or  more  HDCP-protected  Interface  Port  and  is 
designed in adherence to HDCP is referred to as an HDCP Device. 
HDCP Encryption.  HDCP Encryption is the encryption technology of HDCP when applied to 
the protection of HDCP Content in an HDCP System. 
HDCP Receiver.  An HDCP Device that can receive and decrypt HDCP Content through one or 
more of its HDCP-protected Interface Ports is referred to as an HDCP Receiver. 
HDCP Repeater.  An HDCP Device that can receive and decrypt HDCP Content through one or 
more of its HDCP-protected Interface Ports, and can also re-encrypt and emit said HDCP Content 
through one or more of its HDCP-protected Interface Ports, is referred to as an HDCP Repeater.  
An HDCP Repeater may also be referred to as either an HDCP Receiver or an HDCP Transmitter 
when referring to either the upstream side or the downstream side, respectively.  
HDCP  Session.  An  HDCP  Session  is  established  between  an  HDCP  Transmitter  and  HDCP 
Receiver with the transmission or reception of rtx as part of the authentication initiation message, 
AKE_Init.  The  established  HDCP  Session  remains  valid  until  it  is  aborted  by  the  HDCP 
Transmitter or a new HDCP Session is established, which invalidates the HDCP Session that was 
previously  established,  by  the  transmission  or  reception  of  a  new  rtx  as  part  of  the  AKE_Init 
message. 
HDCP  System.    An  HDCP  System  consists  of  an  HDCP  Transmitter,  zero  or  more  HDCP 
Repeaters and one or more HDCP Receivers connected through their HDCP-protected interfaces 
in a tree topology; whereas the said HDCP Transmitter is the HDCP Device most upstream, and 
receives  the Audiovisual  Content from  one or  more Upstream  Content  Control  Functions.  All 
HDCP  Devices  connected  to  other  HDCP  Devices  in  an  HDCP  System  over  HDCP-protected 
Interfaces are part of the HDCP System. 
HDCP Transmitter.  An HDCP Device that can encrypt and emit HDCP Content through one or 
more of its HDCP-protected Interface Ports is referred to as an HDCP Transmitter. 
HDCP.  HDCP is an acronym for High-bandwidth Digital Content Protection.  This term refers to 
this content protection system as described by any revision of this specification and its errata. 
HDCP-protected Interface Port.  A logical connection point on an HDCP Device that supports 
an  HDCP-protected  Interface  is  referred  to  as  an  HDCP-protected  Interface  Port.  A  single 
connection can be made over an HDCP-protected interface port. 
HDCP-protected  Interface.  An interface for which HDCP applies is described as an HDCP-
protected Interface. 
Master  Key.  A  128-bit  random,  secret  cryptographic  key  negotiated  between  the  HDCP 
Transmitter and the HDCP Receiver during Authentication and Key Exchange and used to pair the 
HDCP Transmitter with the HDCP Receiver. 
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Public Key Certificate.  Each HDCP Receiver is issued a Public Key Certificate signed by DCP 
LLC, and contains the Receiver ID and RSA public key corresponding to the HDCP Receiver. 
Receiver Connected Indication. An indication to the HDCP Transmitter that an active receiver 
has  been  connected  to  it.  The  format  of  the  indication  or  the  method  used  by  the  HDCP 
Transmitter to connect to or disconnect from a receiver is outside the scope of this specification. 
Receiver Disconnected Indication. An indication to the HDCP Transmitter that the receiver has 
been  disconnected  from  it.  The  format  of  the  indication  or  the  method  used  by  the  HDCP 
Transmitter to connect to or disconnect from a receiver is outside the scope of this specification.  
Receiver ID.  A 40-bit value that uniquely identifies the HDCP Receiver. It has the same format as 
an HDCP 1.x KSV i.e. it contains 20 ones and 20 zeroes. 
Session  Key.  A  128-bit  random,  secret  cryptographic  key  negotiated  between  the  HDCP 
Transmitter  and  the  HDCP  Receiver  during  Session  Key  exchange  and  used  during  HDCP 
Content encryption or decryption. 
Upstream  Content  Control  Function.    The  HDCP  Transmitter  most  upstream  in  the  HDCP 
System  receives  Audiovisual  Content  to  be  protected  from  the  Upstream  Content  Control 
Function.  The  Upstream  Content  Control  Function  is  not  part  of  the  HDCP  System,  and  the 
methods used, if any, by the Upstream Content Control Function to determine for itself the HDCP 
System is correctly authenticated or permitted to receive the Audiovisual Content, or to transfer the 
Audiovisual  Content  to  the  HDCP  System,  are  beyond  the  scope  of  this  specification.    On  a 
personal  computer  platform,  an  example  of  an  Upstream  Content  Control  Function  may  be 
software  designed  to  emit  Audiovisual  Content  to  a  display  or  other  presentation  device  that 
requires HDCP. 
upstream.  The term, upstream, is used as an adjective to refer to being towards the source of the 
HDCP Content.  For example, when an HDCP Transmitter and an HDCP Receiver are connected 
over  an  HDCP-protected  Interface,  the  HDCP  Transmitter  can  be  referred  to  as  the  upstream 
HDCP  Device  in  this  connection.    For  another  example,  on  an  HDCP  Repeater,  the  HDCP-
protected Interface Port(s) which can receive HDCP Content can be referred to as its upstream 
HDCP-protected Interface Port(s).  See also, downstream.   
1.3  Overview 
1.  HDCP  is  designed  to  protect  the  transmission  of  Audiovisual  Content  between  an  HDCP 
Transmitter  and  an  HDCP  Receiver.  The  HDCP  Transmitter  may  support  simultaneous 
connections to HDCP Receivers through one or more of its HDCP-protected interface ports. 
The  system  also  allows  for  HDCP  Repeaters  that  support  downstream  HDCP-protected 
Interface Ports. The HDCP System allows up to four levels of HDCP Repeaters and as many 
as  32  total  HDCP  Devices,  including  HDCP  Repeaters,  to  be  connected  to  an  HDCP-
protected Interface port.  
Figure 1.1 illustrates an example connection topology for HDCP Devices.  
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