ISO 26430-6:2009 describes the Auditorium Security Message (ASM) specification, which enables interoperable communication of security-critical information (information necessary to ensure security of D-Cinema content) between devices over an intra-theater exhibition network. The specification uses Transport Layer Security (TLS) for authentication and confidentiality, and Key Length Value (KLV) coding for message encoding. It defines a protocol, a general purpose request-response message set and a specific message set for link encryption keying.