DCI Specs - Digital Cinema Initiatives

9.4.2.3. Media Blocks (MBs)The term Media Block 19 (MB) has been used by the Digital Cinema industry in a numberof ways. In this Section 9 SECURITY, it has a very narrow scope: An MB is an SPB thatperforms essence decryption, i.e., it contains at least one MD. Other SE functions mayalso be present within a MB SPB, as described below:• Image Media Block (IMB) – The Image Media Block (IMB) is a type of SecureProcessing Block (SPB) that shall contain a Security Manager (SM), Image,Audio and Subtitle Media Decryptors (MD), image decoder, Image and AudioForensic Marking (FM) and optionally Link Encryptor (LE) functions. The IMB SMis responsible for security for a single auditorium, and it authenticates other SPBsthat are required to participate in showings. Other such SPBs are referred to asremote or external SPBs.• Remote Media Block – A remote Media Block is a remote SPB that containsother types of MDs, such as those used for audio or subtitles, but does notcontain an SM. Remote Media Blocks shall not be used in DCI compliantsystems.9.4.2.4. Security Manager (SM)The SM controls Security Data and content access in a manner consistent with thepolicies agreed upon by the Stakeholders who rely upon it. There is one SM for eachauditorium, and it shall be contained within the IMB. The Rights Owners (Distribution)shall share this SM for their security needs.Security Manager functions shall conform to the requirements as given in Section 9.4.3.5Functions of the Security Manager (SM) and Section 9.6.1 Digital Rights Management.The Security Manager is a self-contained system with an embedded processor and realtimeoperating system. SM functions shall not be implemented outside of the secureenvironment of the Image Media Block (IMB) SPB.The Security Manager is a self-contained processor running a real-time operatingsystem. The operating environment shall be limited to the FIPS 140-2 limited operationalenvironment category (Section 9.5.2.5 FIPS 140-2 Requirements for Type 1 SecureProcessing Blocks), meaning that the SM’s operation shall not be modifiable in the field.The only security communication with systems (processors) external to the SM’s SPBshall be by Transport Layer Security (TLS) over a network interface per Section 9.4.5.1Transport Layer Security Sessions, End Points and Intra-Theater Messaging. Thepreferred real time operating system would use the National Security Agency (NSA)kernel and would be specifically designed for secure operations.. The Security Managersoftware shall use all appropriate security features of the operating system.Security Manager software changes and upgrade requirements are given in Section9.5.2.7 SPB Firmware Modifications.9.4.2.5. Screen Management System (SMS)Theater management controls auditorium security operations through the ScreenManagement System (SMS). Because the SMS interacts and communicates directly19 In Section 7 THEATER SYSTEMS Media Blocks are also discussed. The terminology used there is not strictly securityfocused, because other important equipment requirements such as storage and server functions are discussed. Dependingupon a particular design, server functions may well be part of what is in a MB, when viewed in its entirety. Since othersuch functions are invisible to security, they need not be discussed within the security arena, and are not addressed in thissecurity chapter.DCI Digital Cinema System Specification v.1.2 Page 102