This part of ISO/IEC 24767 specifies security in a home network for equipment with limited IT capability. The Secure Communication Protocol for Middleware (SCPM) is particularly designed to support network security (see 5.2) for equipment not capable of supporting Internet security protocols such as IPSec or SSL/TLS. Although this protocol is designed for unsafe transmissions, it may be used on other types of transmissions. Of course, the quality level of the security services of SCPM is not equal with that of the Internet security protocols but will ensure that such middleware can also be connected securely within a home. It is not the intention that SCPM replace existing security mechanisms of protocols that have already been published. The SCPM provides the security services at the network layer and the protocol does not rely on any specific media transmission. This part of ISO/IEC 24767 contains detailed specifications of the security services supported, the necessary message formats, the information flows and the processing of these pieces of information necessary for the implementation of this protocol. Therefore, this standard neither addresses media-dependent issues nor an overall security architecture covering every home-networking technology. The protocol specified in this standard is media-independent and covers the security services for the network layer for protocols that do not have a conflicting network-layer addressing scheme. Network layer security services are provided through the use of a combination of cryptographic and security mechanisms. Each protocol should specify the details of this security implementation. An HES system supporting more than one protocol needs a gateway in between protocols. Finally, this standard does not define any type of application except for key management which has become essential in any security service. Nonetheless, there are no restrictions on which types of applications may be deployed with SCPM.