DCI Specs - Digital Cinema Initiatives

which it was stopped or paused. It is required that a restart be logged by the SecurityManager, provided that the essence (either image, audio or subtitle) is encrypted.5.3.1.12. Simple EssenceA track file is required to contain essence of a single essence type (e.g., audio, image,subtitles). While a Track File can, for instance, contain all audio channels for a givenlanguage, additional languages are required to be stored in separate track file. TheComposition Playlist will select the correct Track Files to play a requested version of themovie (composition).5.3.2. MXF Track File Encryption5.3.2.1. IntroductionMXF Track File Encryption shall be compliant with SMPTE 429-6-2006 D-CinemaPackaging – MXF Track File Essence Encryption. The following requirements clarify theuse of SMPTE 429-6-2006 with this specification. For the purpose of this section, aframe is defined as an image frame time, for example 24 FPS or 48 FPS.• The encryption shall support KLV encoding as specified in [SMPTE 336M-2001Television – Data Encoding Protocol using Key-Length-Value].• The encrypted audio or image Track File shall be a valid MXF file.• KLV packets shall be encrypted using the Advanced Encryption Standard (AES)block cipher algorithm using a 128 bit key operating in Cipher Block Chaining(CBC) mode, as defined in [NIST Special Publication 800-38A]. See NationalInstitute of Standards and Technology [FIPS PUB 197] (November 26, 2001).• Each reel shall use a single cryptographic key for all frames within the sound orpicture Track File.• The encryption method shall support random access to any frame of essencewithin the sound or picture Track File.• The integrity of each frame of sound and picture essence shall be verifiable usingthe HMAC-SHA1 algorithm. The optional Message Integrity Code (MIC) elementof SMPTE 429-6-2006 shall be present.• There shall be a method for verifying that all frames within a sound and picturetrack are played in correct sequence. The optional TrackFileID andSequenceNumber elements of SMPTE 429-6-2006 shall be present.• The Track File encryption method shall allow for the common header data withineach frame of essence to be plain text. In other words, the encryption of eachframe of essence shall have a programmable offset of “n” bytes such thatcommon header data is left as plaintext.• There shall be a method for verifying that the correct cryptographic key is usedand the essence is being decrypted correctly.• A reference decryption model shall be specified.• Track File encryption shall not require encryption of all frames within a file.• Track File encryption shall be independent of the nature of the underlyingessence and associated metadata.DCI Digital Cinema System Specification v.1.2 Page 50