DCI Specs - Digital Cinema Initiatives

Figure 14: Digital Cinema Security Message Flow9.3.3.2. Security EntitiesSecurity Entities (SE) are characterized by executing in a narrowly defined securityfunction, and having a role defined for them in a digital certificate with which they areassociated. The seven defined SE(s) are as follows (these are developed more fully inSection 9.4 Theater Systems Security).1. Screen Management System (SMS) – The SMS is not a secure device andtherefore is not trusted to handle Security Data (keys). The SMS is trusted tosend/receive commands to/from the auditorium SM, such as those required toprepare an equipment suite for playback.2. Security Manager (SM) – Responsible for Security Data (keys) and Digital RightsManagement within a defined sphere of control (see Section 9.6.2 “Trust” andthe Trusted Device List (TDL))3. Media Decryptor (MD) – Transforms encrypted (image, sound, etc.) content to itsoriginal plaintext form4. Link Encryptor (LE) – Encrypts content transmission over links between physicaldevices in exhibition5. Link Decryptor (LD) – Decrypts content encrypted by a Link Encryptor (LE)6. Forensic Marker (FM) – Inserts markings (data indicating time, date and locationof playback) in both image and audio essence in realtime at time of playback(i.e., a fingerprint or watermark inserter)7. Secure Processing Block (SPB) – A Security Entity (SE) whose security functionis to provide physical protection to other SEs contained within it. A Media Block isan example of a SPB. These specifications define two types of SPB physicalDCI Digital Cinema System Specification v.1.2 Page 96