What types of authorities does XRI support?
XRI supports two overall types of authorities: • IRI authorities, which include the same two types of authorities supported in URIs and IRIs, i.e., IP addresses and DNS names. • XRI authorities, which include two new types of authority identifiers: GCS characters and cross-references (see below.) Since XRI authority syntax is a superset of URI/IRI authority syntax, any authority identifier than can be used in a URI or IRI may also be used in an XRI.