ISO 24165-2:2025

International
Standard
ISO 24165-2
Second edition
Digital token identifier (DTI) —
2025-06
Registration, assignment and
structure —
Part 2:
Data elements for registration
Jeton digital — Enregistrement, affectation et structure —
Partie 2: Données d’enregistrement
Reference number
© ISO 2025
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Constituents of a registry record . 6
4.1 Digital token identifier (DTI).6
4.2 Digital ledger identifier . .7
4.3 Classes of information .7
5 Data elements . 7
5.1 Categories of data elements .7
5.2 Normative data elements for DTI records .8
5.3 Informative data elements for DTI records .9
5.4 Data elements for base record of digital ledger identifier (DLI) .10
5.5 Normative data elements for base record of DLI .11
5.6 Informative data elements for base record of DLI .11
5.7 Data elements for fork record(s) for DLI . 12
5.8 Normative data elements for fork record(s) for DLI . 12
6 Registration authority .13
6.1 Name and contact details of the registration authority . 13
6.2 Service provision for the registration authority . 13
Annex A (normative) Data requirements . 14
Bibliography .18

iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
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with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
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related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 68, Financial services, Subcommittee SC 8,
Reference data for financial services.
This second edition cancels and replaces the first edition (ISO 24165-2:2021), which has been technically
revised.
The main changes are as follows:
— The scope for digital token identifiers (DTIs) has been extended to include non-fungible tokens (NFTs).
— The document now separates DTIs to identify tokens and digital ledger identifiers (DLIs) to identify
ledgers (only ledgers that have one or more DTIs linked to them are in the scope of this document).
— Anchor block information has been added where genesis block is either not known/lost.
— "Functionally fungible group" has been renamed "equivalent digital token group".
— Issuer and maintainer have been added as informative, optional fields.
— "Native token" has been renamed "protocol token".
A list of all parts in the ISO 24165 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
Introduction
With the rise in popularity of peer-to-peer payment systems, these systems rely less on centralized
authorities. Instead, they depend on aspects of cryptography, decentralized processing and a distributed
network. This network maintains a shared record of transaction activity.
As a result, the need to identify the digital tokens issued, traded, transacted or stored on these networks
has grown. Stakeholders in the trading community, service providers, custodians and regulatory bodies
have identified numerous use cases where a standard identifier for accounting, research, tracking and
management of these digital tokens would improve efficiency and eliminate confusion in the marketplace.
However, the nature of these new types of digital asset means they do not fit within the structure of existing
ISO identifiers, in part because they can lack clear reference to an issuing authority and will therefore not
be considered the liability of an issuing authority or corporate governing body. These digital assets, in many
cases, extend across various regions and monetary governance jurisdictions.
Though these digital assets are sometimes referred to as cryptocurrencies, virtual currencies or digital
currencies, the term "currency" has a specific meaning as defined by ISO 4217. This definition is in conflict
with the nature of the digital tokens identified in this document due to the reasons described above; namely,
the lack of monetary authority and geographic location.
Where traditional financial instruments or currencies are tokenized for electronic exchange and issued by
a legal entity including the monetary authority responsible for it, other International Standards, such as
ISO 6166 or ISO 4217, can apply. To eliminate confusion for users of this document, care has been taken to
provide a clear definition and eligibility criteria for assignment of a digital token identifier (DTI) and digital
ledger identifier (DLI).
This document is addressed to applicants seeking to identify digital tokens that conform to the definition
provided in ISO 24165-1. The data elements described in this document are used to distinguish one set
of digital tokens and ledgers from another and are, wherever possible, objective and publicly available.
Inclusion in the registry and the issuance of an identifier signifies only the existence of the token and/or
ledger and its 1:1 relationship to its identifier.
The ISO 24165 series is organized into the following parts:
— ISO 24165-1 describes the method of registration and assignment of a DTI and a DLI.
— ISO 24165-2 describes the data elements required for registration and display on the DTI and DLI registry.

v
International Standard ISO 24165-2:2025(en)
Digital token identifier (DTI) — Registration, assignment and
structure —
Part 2:
Data elements for registration
1 Scope
This document defines the data elements included in the registry record and used to establish the 1:1
relationship between a digital token and the identifier assigned according to the method in ISO 24165-1.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO/IEC 10646, Information technology — Universal coded character set (UCS)
ISO 24165-1, Digital token identifier—Registration, assignment and structure—Part 1: Method for registration
and assignment
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
anchor block
earliest known and verifiable block in a blockchain
Note 1 to entry: The anchor block is typically the blockchain genesis block (3.33).
3.2
anchor block hash
block hash (3.10) of the anchor block
Note 1 to entry: The anchor block hash is typically recorded in the block immediately following the anchor block.
3.3
anchor block hash algorithm
block hash algorithm (3.11) used to produce the block hash (3.10) of the anchor block (3.1)
3.4
anchor block height
block height (3.13) of the anchor block (3.1)

3.5
anchor block UTC timestamp
timestamp recorded in the anchor block (3.1)
Note 1 to entry: Frequently, the anchor block UTC timestamp is located in the anchor block header (data structure that
includes a cryptographic link to the previous block [ISO 22739:2024, 3.4]) .
Note 2 to entry: The anchor block UTC timestamp is expressed in Coordinated Universal Time.
3.6
auxiliary digital token
non-protocol digital token (3.51) created as an application on an existing blockchain or other distributed
ledger technology for its issuance, storage or transaction record which is explicitly identified within the
distributed ledger technology protocol
Note 1 to entry: A distributed ledger may support zero or more auxiliary digital tokens.
3.7
auxiliary digital token distributed ledger
assigned digital ledger identifier of the distributed ledger used for issuance, storage or transaction record of
an auxiliary digital token (3.6)
EXAMPLE If registering an ERC-20 token operating on the Ethereum blockchain, this data element will contain
...