Namespace Registration for International Standard Name Identifier (ISNI) Namespace ID: ISNI Version: 1.0 Date: 2025-10-15 Registrant: Name: Paul Jessop E-mail: info&isni.org Affiliation: Adviser to ISNI International Agency (ISNI-IA) Address: c/o EDItEUR, United House, North Road, London, N7 9DP, UK Web URL: https://isni.org Purpose: The purpose of the ISNI namespace is to allow the representation of ISNI identifiers as URNs. An ISNI is an identifier for the public identity of a party in the media content industry - that is, the identity presented to the public. ISNI is an international standard under ISO 27729 and ISO has appointed the ISNI International Agency (ISNI-IA) as the registration authority. ISNI-IA publishes documentation explaining how to implement ISNI and revises this from time to time. Advice is available on the ISNI-IA website at https://isni.org and includes information on implementation details that are not contained in the international standard. ISNI does not identify the underlying natural or legal person, and several ISNIs may be associated with such a person if it presents multiple identities (such as personas) to the public. It is possible to resolve an ISNI by using the website or by prepending https://isni.org/isni/ and performing an http GET. The resolution process may include one or more HTTP redirections. The following benefits are envisaged: 1. When represented as URNs, ISNIs are fully compliant URIs as required by certain systems. 2. When represented as URNs, ISNIs can be easily located within text by machines and humans, even without the resolver address https://isni.org/isni/. 3. When represented as URNs, ISNIs can in the future become technology independent hyperlinks without the proxy address. 4. URN Q- and R-components might in the future be used with ISNI in order to send requests to the target system or resolver, provided that the ISNI resolver is enhanced with support for these URN features. Syntax: The ISNI Namespace-Specific String (NSS) follows the syntax and content of the represented ISNI, as specified in ISO 27729. The NSS comprises a fixed length string of 16 characters consisting of 15 decimal digits and a check digit which is either a decimal digit or the alphabetic character "X". The use of a lower-case "x" is strictly non-conformant but in practice, systems may treat is as its upper-case equivalent. ISO 27729 requires that when an ISNI is "written, printed or otherwise presented in a human-readable format" it is preceded by "ISNI" and a space, and split into blocks of four characters separated by a space. This does not affect the identifier itself which is the sixteen characters. EXAMPLE "0000000121241960" is the ISNI of Elvis Presley. "ISNI 0000 0001 2124 1960" should appear on-screen. "urn:isni:0000000121241960" is the URN-ISNI for the same referent. The following formal definition uses ABNF [RFC5234]. URN-ISNI = "urn:isni:" ISNI-NSS ISNI-NSS = 15DIGIT ISNI-CHECK-DIGIT DIGIT = %x30-39 ISNI-CHECK-DIGIT = DIGIT / %x58 Rules for lexical equivalence: Two URN-ISNIs are equivalent if corresponding characters of each ISNI-NSS are identical. It is recommended that a strictly non-conformant lower case "x" as the check-digit be converted to an upper-case "X" before comparison is made. URN F-, Q- and R-components SHALL be ignored in the comparison since they are not part of the NSS. Because the ISNI-NSS has the same content as the corresponding ISNI, the same test can be applied to the comparison of a URN-ISNI and an ISNI. Where comparison is made between a URN-ISNI and the presentation format of an ISNI, the prefixed "ISNI" and the spaces shall be removed before comparison is attempted. EXAMPLE The following representations of an ISNI name SHALL be regarded as equivalent: 0000000121241960 ISNI 0000 0001 2124 1960 urn:isni:0000000121241960 Assignment: ISNI assignment is managed by ISNI-IA through its registration agencies and the appointed assignment agency. Their roles and responsibilities are documented on the ISNI website. Uniqueness: The assignment of an ISNI requires that the applicant provide sufficient disambiguating information to describe the identity to the degree necessary to distinguish it as a separate name within the ISNI system. Where two ISNIs are later discovered to refer to the same identity, these registrations are merged but the unused ISNI is retained yet marked as deprecated and aliased to the preferred ISNI. The effect of these policies is that there is exactly one information record associated with each assigned ISNI. This record is managed to represent a single name. Because a single party may present multiple identities (such as personas) with different names, there may be several ISNIs associated with that party. ISNI-IA publishes guidance on when multiple names associated with an entity should (a) be regarded as different identities and assigned different ISNIs and when they should (b) be regarded as name-variants of the same identity. Persistence of ISNI information is a key aim of the ISNI system and is a key objective of ISNI-IA which has sustainability as a prime operating target. Security and Privacy: ISNIs do not have any unmanaged privacy issues. Detailed examination has assured ISO and ISNI-IA that the ISNI system is in compliance with privacy and data protection requirements such as the General Data Protection Regulation of the EU and the California Consumer Privacy Act. Interoperability: ISNIs do not have any known interoperability related problems. ISNI registrations may contain other identifiers relating to the same identity and routinely do so. These other identifiers can be accessed when resolving an ISNI. Resolution: URNs in the URN:ISNI namespace SHALL be resolvable. Each resolution of a URN in the URN:ISNI namespace SHALL return information about the identity represented by the ISNI in the ISNI-NSS. To resolve a URN in the URN:ISNI namespace, the string to the right of "urn:isni: " is prepended with "https://isni.org/isni/" and an https GET is performed. The ISNI website contains information on how to use the ISNI resolution process with parameters to allow access to the registered information in specific formats. Additional documentation / information: See ISO 27729 and the ISNI Website at https://isni.org. Revision Information: None