ISO 21091:2013 defines minimal specifications for directory services for healthcare. It can be used to enable communications between organizations, devices, servers, application components, systems, technical actors, and devices. ISO 21091:2013 provides the common directory information and services needed to support the secure exchange of healthcare information over public networks where directory information and services are used for these purposes. It addresses the health directory from a community perspective in anticipation of supporting inter-enterprise, inter-jurisdiction, and international healthcare communications. While several options are supported by ISO 21091:2013, a given service will not need to include all of the options. In addition to the support of security services, such as access control and confidentiality, ISO 21091:2013 provides specification for other aspects of communication, such as addresses and protocols of communication entities. ISO 21091:2013 also supports directory services aiming to support identification of health professionals and organizations and the subjects of care.