Blockchain and distributed ledger technologies — Taxonomy and Ontology

This document specifies a taxonomy and an ontology for blockchain and distributed ledger technologies (DLT). The taxonomy includes a taxonomy of concepts, a taxonomy of DLT systems and a taxonomy of application domains, purposes and economy activity sections for use cases. The ontology includes classes and attributes as well as relations between concepts. The audience includes but is not limited to academics, architects, customers, users, tool developers, regulators, auditors and standards development organizations.

Technologies des chaînes de blocs et technologies de registre distribué — Taxinomie et ontologie

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Status
Published
Publication Date
01-Nov-2021
Current Stage
6060 - International Standard published
Completion Date
02-Nov-2021
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TECHNICAL ISO/TS
SPECIFICATION 23258
First edition
2021-11
Blockchain and distributed ledger
technologies — Taxonomy and
Ontology
Technologies des chaînes de blocs et technologies de registre
distribué — Taxinomie et ontologie
Reference number
ISO/TS 23258:2021(E)
© ISO 2021
---------------------- Page: 1 ----------------------
ISO/TS 23258:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on

the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below

or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
© ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/TS 23258:2021(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction .................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ..................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 1

4 Abbreviated terms ............................................................................................................................................................................................. 1

5 Taxonomy ....................................................................................................................................................................................................................2

5.1 Introduction .............................................................................................................................................................................................. 2

5.2 Taxonomy of concepts ...................................................................................................................................................................... 2

5.3 Taxonomy of DLT systems ......................................................................................................................................................... 12

5.3.1 General .....................................................................................................................................................................................12

5.3.2 Major characteristics of DLT systems ..........................................................................................................12

5.4 Taxonomy of application domains, purposes and economic activity sections for

use cases ........................................................................................................................................... ......................................................... 17

5.4.1 General ..................................................................................................................................................................................... 17

5.4.2 Cross-sector application domains .................................................................................................................... 17

5.4.3 Cross-sector use cases purposes ...................................................................................................................... 19

5.4.4 Economic activity sections ..................................................................................................................................... 21

6 Ontology .....................................................................................................................................................................................................................22

6.1 Introduction ........................................................................................................................................................................................... 22

6.2 Ledger Class ........................................................................................................................................................................................... 22

6.3 Distributed ledger class ............................................................................................................................................................... 23

6.4 Blockchain class .................................................................................................................................................................................. 23

6.5 Block class ................................................................................................................................................................................................ 24

Annex A (informative) Classification of DLT system based on the taxonomy of DLT systems ............25

Annex B (informative) Context from use-case classification .................................................................................................26

Bibliography .............................................................................................................................................................................................................................28

iii
© ISO 2021 – All rights reserved
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ISO/TS 23258:2021(E)
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 has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely 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).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions 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 307, Blockchain and distributed ledger

technologies.

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.
© ISO 2021 – All rights reserved
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ISO/TS 23258:2021(E)
Introduction

A taxonomy is useful for defining information and data classification rules and for identifying

classification items and classification criteria. An ontology aims at clearly showing the concepts that

make up the conceptual basis and the vocabulary of the technology under consideration and at creating

a foundation that is a prerequisite for understanding the concepts through the definition of their mutual

relations (synonyms, inclusions, dependencies, etc.).

A consistent taxonomy is a valuable resource in its own right that also supports and helps to understand

other relevant standards.

This document includes a taxonomy of concepts, a taxonomy of DLT systems, and a taxonomy of

application domains, purposes and economic activity sections for use cases. This document includes an

ontology providing classes and attributes as well as relations between concepts.

Figure 1 shows the relationships between this document and other standards developed by ISO/TC 307.

Key
feedback
direction of input
affects each other

Figure 1 — Relationships between this document and other standards developed by ISO/TC 307

© ISO 2021 – All rights reserved
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TECHNICAL SPECIFICATION ISO/TS 23258:2021(E)
Blockchain and distributed ledger technologies —
Taxonomy and Ontology
1 Scope

This document specifies a taxonomy and an ontology for blockchain and distributed ledger technologies

(DLT). The taxonomy includes a taxonomy of concepts, a taxonomy of DLT systems and a taxonomy

of application domains, purposes and economy activity sections for use cases. The ontology includes

classes and attributes as well as relations between concepts.

The audience includes but is not limited to academics, architects, customers, users, tool developers,

regulators, auditors and standards development organizations.
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 22739, Blockchain and distributed ledger technologies — Vocabulary
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 22739 and the following 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
taxonomy

scheme of categories and subcategories that can be used to sort and otherwise organize itemized

knowledge or information
[SOURCE: ISO 5127:2017, 3.8.6.07]
4 Abbreviated terms
DLT Distributed Ledger Technology
PoW Proof-of-Work
PoS Proof-of-Stake
DPoS Delegated Proof-of-Stake
BFT Byzantine Fault Tolerance
PBFT Practical Byzantine Fault Tolerance
TPS Transaction Per Second
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ISO/TS 23258:2021(E)
CA Certificate Authority
IPFS InterPlanetary File System
UML Unified Modeling Language
5 Taxonomy
5.1 Introduction

To better understand DLT systems, it is necessary to classify them into different categories based

on their similarities on different aspects. Such classification is also known as the taxonomy of DLT

systems. To be able to thoroughly classify and correlate DLT systems, it is imperative to investigate

and understand the existing blockchain and distributed ledger technologies as well as the relationships

among the DLT system options. This taxonomy helps the potential blockchain users and other

stakeholders to compare and choose the right options according to their business needs and applicable

legal and regulatory requirements. Furthermore, the ability to classify DLT systems can help with

knowledge advancement and can lead to a significant breakthrough in understanding and utilization

of DLT systems. Furthermore, the taxonomy informs the scientific research and could support wider

understanding and adoption of blockchain and distributed ledger technologies and systems.

5.2 Taxonomy of concepts

Table 1 is based on and refers to the terms and definitions in ISO 22739:2020, ISO 23257:— and

completed with some of the concepts used in Reference [1]. It organizes the concepts into 6-level

hierarchical structure with only one entry per concept. Short forms of concepts are given in square

brackets and references are provided in parentheses, e.g. “[DLT user (ISO 22739:2020, 3.28)].”

Table 1 — Taxonomy of concepts

Level 1 con- Level 2 concepts Level 3 con- Level 4 conceptsLevel 5 concepts Level 6 concepts

cepts cepts
Asset (ISO Digital Asset Cryptographic Cryptocurrency
22739:2020, (ISO 22739:2020, Asset (ISO 22739:2020,
3.1) 3.20) 3.14)
(Crypto-as-
Token (ISO (Token) Fungi- Fungible Token
set ) (ISO
22739:2020, bility (Fungible
22739:2020,
Non-Fungible
3.76) (ISO 23257:—,
3.13)
Token [NFT]
3.12)
Token Metadata Digital Asset De-
scription
Privilege Descrip-
tion
Value Description
(Asset) Prov- Origin of Asset
enance (ISO
History of Asset
23257:—, 3.11)
History of Cus-
tody
1) Under preparation. Stage at the time of publication: ISO/FDIS 23257:2021.
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ISO/TS 23258:2021(E)
Table 1 (continued)

Level 1 con- Level 2 concepts Level 3 con- Level 4 conceptsLevel 5 concepts Level 6 concepts

cepts cepts
Consensus (ISO Consensus Fault Tolerance Byzantine Fault Practical Byzan-
22739:2020, Mechanism (ISO Tolerance [BFT] tine Fault Toler-
3.11) 22739:2020, ance [PBFT]
3.12)
Crash Fault Tol-
erance
Nakamoto Con- Proof of Stake Delegated Proof
sensus [PoS] of Stake [DPoS]
Proof of Work
[PoW]
Consensus Secu-
rity
Smart Con- Legally Binding
tract (ISO Smart Contract
22739:2020,
3.72)
Entity (ISO Legal Entity Group
22739:2020,
3.34)
Organization Autonomous Decentralized
Organization Autonomous Or-
ganization [DAO]
Person Operator Distributed
Ledger Technolo-
gy Operator [DLT
Operator]
User D is t r i b u te d
Ledger Technol-
ogy User (ISO
22739:2020, 3.31)
[DLT User (ISO
22739:2020, 3.31)]
Process Action Confirmation Block Confirma-
tion
Transaction Con-
firmation
Compliance
Deletion (Delete Transaction
ISO 23257:—, Deletion
3.2)
Execution Execution of Stateful Execution
Contract of Contract
Stateless Execution
of Contract
Validation (ISO Block Validation
22739:2020,
Ledger Record
3.82)
Validation
Transaction Vali-
dation
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ISO/TS 23258:2021(E)
Table 1 (continued)

Level 1 con- Level 2 concepts Level 3 con- Level 4 conceptsLevel 5 concepts Level 6 concepts

cepts cepts
Activity Archiving Data Archiving
(Archive ISO (ISO 23257:—,
23257:—, 3.3) 3.4)
Resource Archiv-
ing
Transaction
Archiving
Hashing
Mining (ISO
22739:2020,
3.49)
Restoring Data Restoring
(Restore
Resource Restor-
ISO 23257:—,
ing
3.6)
Transaction
Restoring
Event Disruption (ISO Attack
23257:—, 3.10)
Incident (ISO
23257:—, 3.8)
Error Error analytics
Failure (ISO
22739:2020,
3.35)
Fault Fault Tolerance
(ISO 22739:2020,
3.36)
Fork (ISO Hard Fork (ISO
22739:2020, 22739:2020,
3.45) 3.38)
Soft Fork (ISO
22739:2020,
3.73)
Work Process Backup (ISO Data Backup
23257:—, 3.5)
Resource Backup
Transaction
Backup
Transaction
(ISO 22739:2020,
3.77)
Thing Object Device
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ISO/TS 23258:2021(E)
Table 1 (continued)

Level 1 con- Level 2 concepts Level 3 con- Level 4 conceptsLevel 5 concepts Level 6 concepts

cepts cepts
Node (ISO Child Node
22739:2020,
Distributed Miner (ISO
3.50)
Ledger Tech- 22739:2020, 3.48)
nology Node
Participant
[DLT Node (ISO
Validator (ISO
22739:2020,
b 22739:2020, 3.83)
3.27)]
Leaf Node (ISO
22739:2020,
3.42)
Non-Leaf Node
Parent Node
Peer
Root Node (ISO (Node) Merkle
22739:2020, Root (ISO
3.69) 22739:2020, 3.46)
Platform Distributed
Ledger Tech-
nology Platform
[DLT Platform
(ISO 22739:2020,
3.29)]
Governance Control Decentralized
Control
Governance Rule
Incentive Incentive Mech- Reward System Block Reward
anism (ISO (ISO 22739:2020, (ISO 22739:2020,
22739:2020, 3.68) 3.5)
3.68)
Interoper- Transport Inter-
ability (ISO operability
22739:2020,
Syntactic Inter-
3.41)
operability
Semantic Inter-
operability
Behavioral Inter-
operability
Policy Interoper-
ability
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ISO/TS 23258:2021(E)
Table 1 (continued)

Level 1 con- Level 2 concepts Level 3 con- Level 4 conceptsLevel 5 concepts Level 6 concepts

cepts cepts
Ledger (ISO Distributed Blockchain (ISO
22739:2020, Ledger (ISO 22739:2020, 3.6)
3.43) 22739:2020,
3.22)
Distributed Distributed
Ledger Control Ledger Control
Architecture
Distributed
Ledger Privilege
Distributed
Ledger Pruning
(Prune (ISO
22739:2020,
3.63)
Distributed Distributed
Ledger Storage Ledger Storage
Architecture
Shared
Ledger (ISO
22739:2020,
3.70)
Ledger Imple- Block (ISO Block Data (ISO
mentation 22739:2020, 3.2) 22739:2020, 3.3)
Block Header (Block) Hash
(ISO 22739:2020, Value (ISO
3.4) 22739:2020,
3.39)
(Block) Merkle
Root
(Block) Nonce
(ISO 22739:2020,
3.51)
Block Number (or Genesis Block
Block Height) (ISO 22739:2020,
3.37)
Previous Block
(Block) Times-
tamp (ISO
22739:2020,
3.75)
Block Status Confirmed (ISO
22739:2020,
3.8) Block (ISO
22739:2020, 3.9)
Validated (ISO
22739:2020,
3.81) Block
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ISO/TS 23258:2021(E)
Table 1 (continued)

Level 1 con- Level 2 concepts Level 3 con- Level 4 conceptsLevel 5 concepts Level 6 concepts

cepts cepts
Ledger Status Inconsistent Double Spend-
Ledger ing (ISO
22739:2020,
3.33)
Ledger
Split (ISO
22739:2020,
3.45)
Ledger Tamper Tamper-Resist-
Resistance ant
Traditional
Ledger
Permission Hybrid Permis-
sion
Permissioned Permissioned Permissioned Permissioned
(ISO 22739:2020, Distributed Blockchain Private Block-
3.57) Ledger chain
Permissioned
Public Block-
chain
Permis- Permissioned
sioned DLT Blockchain Sys-
System (ISO tem
22739:2020,
3.58)
Permissionless Permissionless Permissionless Permissionless
(ISO 22739:2020, Distributed Blockchain Private Block-
3.59) Ledger chain
Permissionless
Public Block-
chain
Permission- Permissionless
less DLT Blockchain Sys-
System (ISO tem
22739:2020,
3.60)
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ISO/TS 23258:2021(E)
Table 1 (continued)

Level 1 con- Level 2 concepts Level 3 con- Level 4 conceptsLevel 5 concepts Level 6 concepts

cepts cepts
Record (ISO Ledger Record (Ledger Re- Immutable
22739:2020, (ISO 22739:2020, cord) Immu-
3.67) 3.44) tability (ISO
22739:2020,
3.40)
Ledger Record Validated (ISO
Status 22739:2020,
3.81) Ledger
Record
Transaction Transaction Fee
Record (ISO (ISO 22739:2020,
22739:2020, 3.78)
3.79)
(Transaction)
Hash Value (ISO
22739:2020,
3.39)
(Transaction)
Nonce (ISO
22739:2020,
3.51)
(Transaction)
Timestamp (ISO
22739:2020,
3.75)
Transaction Confirmed (ISO
Status 22739:2020, 3.8)
Transaction
(ISO 22739:2020,
3.10)
Validated (ISO
22739:2020,
3.81) Transac-
tion
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ISO/TS 23258:2021(E)
Table 1 (continued)

Level 1 con- Level 2 concepts Level 3 con- Level 4 conceptsLevel 5 concepts Level 6 concepts

cepts cepts
Security Authentication User Authenti- Password
cation
Authorization User Authoriza-
tions
Cryptography Asymmetric Public Key
(ISO 22739:2020, Cryptography Cryptography
3.17) (ISO 22739:2020,
3.66)
Cryptographic Cryptographic Hash Value (ISO
Technique Hash Function 22739:2020,
(ISO 22739:2020, 3.39)
3.15)
Cryptograph-
ic Link (ISO
22739:2020,
3.16)
Cryptographic Tree Data Struc- Merkle Tree (ISO
Tree ture 22739:2020, 3.47)
Digital Sig-
nature (ISO
22739:2020,
3.21)
Encryption Key Private Key (ISO
22739:2020, 3.62)
Public Key (ISO
22739:2020, 3.65)
Decryption
Encryption
Identifiable In- Personally
formation Identifiable In-
formation [PII
(ISO 23257:—,
3.1)]
Identity Manage- Identity Self-Sovereign
ment Identity [SSID]
Integrity Check Integrity
Privacy Manage-
ment
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ISO/TS 23258:2021(E)
Table 1 (continued)

Level 1 con- Level 2 concepts Level 3 con- Level 4 conceptsLevel 5 concepts Level 6 concepts

cepts cepts
Service Application Decentralized
Application
[DApp (ISO
22739:2020,
3.18)]
Wallet (ISO Account Distributed
22739:2020, Ledger Technol-
3.84) ogy
Account [DLT
Account (ISO
22739:2020,
3.24)]
Address Distributed
Ledger Tech-
nology Address
[DLT Address
(ISO 22739:2020,
3.25)]
Hardware Wallet
Software Wallet
Cloud Service Blockchain as a
Service [BaaS]
Oracle Distribut-
ed Ledger
Technology
Oracle [DLT
Oracle (ISO
22739:2020,
3.28)]
System Decentralized
System (ISO
22739:2020,
3.19)
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ISO/TS 23258:2021(E)
Table 1 (continued)

Level 1 con- Level 2 concepts Level 3 con- Level 4 conceptsLevel 5 concepts Level 6 concepts

cepts cepts
Distributed Distribut- Blockchain Off-Chain (ISO
System (ISO ed Ledger System (ISO 22739:2020,
22739:2020, System [DLT 22739:2020, 3.7) 3.52)
3.32) System (ISO
On-Chain (ISO
22739:2020,
22739:2020,
3.30)]
3.54)
Sidechain (ISO Associated Block-
22739:2020, chain System
3.71)
Main chain
Subchain (ISO
22739:2020,
3.74)
Off-Ledger (ISO
22739:2020,
3.53)
On-Ledger (ISO
22739:2020,
3.55)
Private Distrib-
uted Ledger
(Technology)
System [Private
DLT System
(ISO 22739:2020,
3.61)]
Public Distrib-
uted Ledger
(Technology)
System [Public
DLT System
(ISO 22739:2020,
3.64)]
Ecosystem Token Ecosys-
tem
Subsystem Network Distributed
Ledger Technol-
ogy
Network [DLT
Network (ISO
22739:2020,
3.26)]
Peer-To-Peer
(ISO 22739:2020,
3.56) Network
(System) Re-
silience (ISO
23257:—, 3.7)
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ISO/TS 23258:2021(E)
Table 1 (continued)

Level 1 con- Level 2 concepts Level 3 con- Level 4 conceptsLevel 5 concepts Level 6 concepts

cepts cepts
Technology Information
and Communi-
cation Technol-
ogy [ICT (ISO
23257:—, 3.9)]
Ledger Technol- Distribut- Blockchain Tech-
ogy ed Ledger nology
Technology
[DLT (ISO
22739:2020,
3.23)]
Trust (ISO Product Confi-
22739:2020, dence
3.80)
Service Confi-
dence

Group can be a group of items including legal entity, person, process, thing according to ISO

22739:2020, 3.34.

DLT Node may be below Device or Process and was set below Object to avoid duplicate.

Non-cryptographic assets are not covered e.g. when token is considered as a subclass of cryptographic

asset (or crypto-asset), token refers to cryptographic token (or crypto-token).
5.3 Taxonomy of DLT systems
5.3.1 General

The taxonomy of DLT systems is based on several key aspects including whether it is permissioned or

permissionless, the type of consensus mechanism and the existence of incentive mechanisms. Such a

classification helps the companies and organizations to understand and differentiate DLT systems.

5.3.2 Major characteristics of DLT systems
5.3.2.1 General

To provide classification for DLT systems, it is required to analyse them into various categories based

on their similarities on different aspect through main characteristics. See Annex A for an example for

classification of DLT system based on the taxonomy of DLT systems.
5.3.2.2 Purpose of DLT system

DLT systems (including blockchain systems) are designed to implement tamper-resistant distributed

ledgers, using consensus for maintaining a ledger in a distributed network of DLT nodes. Incentives in

DLT systems can drive the achievement of consensus among decision makers, the resolution of conflicts

and the taking of decisions regarding the ongoing governance, design and operation of systems.

Business purpose of DLT systems defines the essential concepts associated with these systems. For

example, Bitcoin system is to allow people to store and transfer value securely and anonymously.

Therefore, the purpose of the Bitcoin system can be described as a payment.
5.3.2.3 Ledger design

Blockchain is one of the most popular ledger designs in the industry. However another systems might

apply a different type of ledger design like DAG (Directed Acyclic Graph) to commit their specific

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ISO/TS 23258:2021(E)

requirements, for example, Internet of Things. In addition, new ledger designs might be continuously

inspired by developers of DLT system in the future.

Blockchain is a distributed ledger with confirmed blocks organized in an append-only, sequential chain

using cryptographic links. This distributed ledger forms a linear chain of blocks of transactions in an

unalterable, chronological order. Transactions are bundled into blocks of transactions to be validated.

Validated blocks are added to a chain of previously validated blocks.

By comparison, a DAG is a network of individual transactions linked to multiple other transactions.

There are no blocks of transactions in DAG networks. If blockchain is a linked list, a DAG is a tree,

branching out from one transaction to another, to another and so on.

Blockchain offers transparency and immutability. It is also relatively well established, being the basis of

cryptocurrencies like Bitcoin and of distributed application (Dapp) platforms like Ethereum. Blockchain

offers solid guarantees and cost-effectiveness for transactions of medium to high value.

By scaling very efficiently and avoiding or reducing user fees, DAGs are well suited to high volumes of

transactions, including micro and nano-transactions. The higher the volume of transactions, the faster

a DAG validates them. DAGs also cut out the need for miners and in turn mining equipment — meaning

lower energy consumption.
5.3.2.4 DLT system permission
5.3.2.4.1 General

According to whether it is requiring permissions to use or operate the system, the types of DLT systems

can be classified as permissionless and permissioned DLT systems.

A permissionless DLT system doesn’t require any permission in order to use the system as a DLT user

or to participate in operation of the system as a DLT node. By contrast a permissioned DLT system does

require some permissions in order to perform a particular activity or activities.

5.3.2.4.2 Permissioned DLT system

In a permissioned DLT system, permissions are required for some capabilities to use the system or

permissions are required for some capabilities to operate the system. Therefore, any participant who

wants to use the system or join to run the DLT network needs to request and get an approval from the

host of the system before they access and use the permissioned DLT system.

In the aspect of operating the system, all DLT nodes of permissioned DLT system are authorized to join

the network and participate in the consensus process to build the blockchain or distributed ledger. In

such system, there might be a central authority which determines and controls the permission for a DLT

node to join the network as well as restricts the DLT nodes on which can participate in the consensus

process to validate block transactions and propose blocks.

In the aspect of DLT user, permissioned DLT system can restrict access for DLT users who use services

provided by DLT system. In such system, all the users should have a per
...

TECHNICAL ISO/TS
SPECIFICATION 23258
First edition
Blockchain and distributed ledger
technologies — Taxonomy and
Ontology
PROOF/ÉPREUVE
Reference number
ISO/TS 23258:2021(E)
ISO 2021
---------------------- Page: 1 ----------------------
ISO/TS 23258:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii PROOF/ÉPREUVE © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/TS 23258:2021(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Symbols and abbreviated terms ........................................................................................................................................................... 1

5 Taxonomy ..................................................................................................................................................................................................................... 2

5.1 Introduction .............................................................................................................................................................................................. 2

5.2 Taxonomy of concepts ...................................................................................................................................................................... 2

5.3 Taxonomy of DLT systems ..........................................................................................................................................................10

5.3.1 General...................................................................................................................................................................................10

5.3.2 Major characteristics of DLT systems .........................................................................................................10

5.4 Taxonomy of application domains, purposes and economic activity sections for

use cases ....................................................................................................................................................................................................15

5.4.1 General...................................................................................................................................................................................15

5.4.2 Cross-sector application domains .................................................................................................................15

5.4.3 Cross-sector use cases purposes .....................................................................................................................17

5.4.4 Economic activity sections ...................................................................................................................................19

6 Ontology .....................................................................................................................................................................................................................20

6.1 Introduction ...........................................................................................................................................................................................20

6.2 Ledger Class ............................................................................................................................................................................................20

6.3 Distributed ledger class ................................................................................................................................................................21

6.4 Blockchain class ..................................................................................................................................................................................21

6.5 Block class ................................................................................................................................................................................................22

Annex A (informative) Classification of DLT system based on the taxonomy of DLT systems ................23

Annex B (informative) Context from use-case classification ....................................................................................................24

Bibliography .............................................................................................................................................................................................................................26

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ISO/TS 23258:2021(E)
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 has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely 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).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions 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 307, Blockchain and distributed ledger

technologies.

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.
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ISO/TS 23258:2021(E)
Introduction

A taxonomy is useful for defining information and data classification rules and for identifying

classification items and classification criteria. An ontology aims at clearly showing the concepts that

make up the conceptual basis and the vocabulary of the technology under consideration and at creating

a foundation that is a prerequisite for understanding the concepts through the definition of their mutual

relations (synonyms, inclusions, dependencies, etc.).

A consistent taxonomy is a valuable resource in its own right that also supports and helps to understand

other relevant standards.

This document includes a taxonomy of concepts, a taxonomy of DLT systems, and a taxonomy of

application domains, purposes and economic activity sections for use cases. This document includes an

ontology providing classes and attributes as well as relations between concepts.

Figure 1 shows the relationships between this document and other standards developed by TC 307.

Key
feedback
direction of input
affects each other

Figure 1 — Relationships between this document and other standards developed by ISO/TC 307

© ISO 2021 – All rights reserved PROOF/ÉPREUVE v
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TECHNICAL SPECIFICATION ISO/TS 23258:2021(E)
Blockchain and distributed ledger technologies —
Taxonomy and Ontology
1 Scope

This document specifies a taxonomy and an ontology for blockchain and distributed ledger technologies

(DLT). The taxonomy includes a taxonomy of concepts (terms), a taxonomy of DLT systems and a

taxonomy of application domains, purposes and economy activity sections for use cases. The ontology

includes classes and attributes as well as relations between concepts.

The audience includes but is not limited to academics, architects, customers, users, tool developers,

regulators, auditors and standards development organizations.
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 22739, Blockchain and distributed ledger technologies — Vocabulary
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 22739 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at http:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
taxonomy

scheme of categories and subcategories that can be used to sort and otherwise organize itemized

knowledge or information
[SOURCE: ISO 5127:2017, 3.8.6.07]
4 Symbols and abbreviated terms
DLT Distributed Ledger Technology
PoW Proof-of-Work
PoS Proof-of-Stake
DPoS Delegated Proof-of-Stake
BFT Byzantine Fault Tolerance
PBFT Practical Byzantine Fault Tolerance
TPS Transaction Per Second
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ISO/TS 23258:2021(E)
CA Certificate Authority
IPFS InterPlanetary File System
UML Unified Modeling Language
5 Taxonomy
5.1 Introduction

To better understand DLT systems, it is necessary to classify them into different categories based

on their similarities on different aspects. Such classification is also known as the taxonomy of DLT

systems. To be able to thoroughly classify and correlate DLT systems, it is imperative to investigate

and understand the existing blockchain and distributed ledger technologies as well as the relationships

among the DLT system options. This taxonomy helps the potential blockchain users and other

stakeholders to compare and choose the right options according to their business needs and applicable

legal and regulatory requirements. Furthermore, the ability to classify DLT systems can help with

knowledge advancement and can lead to a significant breakthrough in understanding and utilization

of DLT systems. Furthermore, the taxonomy informs the scientific research and could support wider

understanding and adoption of blockchain and distributed ledger technologies and systems.

5.2 Taxonomy of concepts

Table 1 is based on and refers to the terms and definitions in ISO 22739:2020, ISO 23257:2021 and

completed with some of the concepts used in Reference [1]. It organizes the concepts into 6-level

hierarchical structure with only one entry per concept. Short forms of concepts are given in square

brackets and references are provided in parentheses, e.g. “[DLT user (ISO 22739:2020, 3.28)].”

Table 1 — Taxonomy of concepts

Level 1 concepts Level 2 concepts Level 3 concepts Level 4 concepts Level 5 concepts Level 6 concepts

Asset (ISO Digital Asset (ISO Cryptographic Cryptocurrency
22739:2020, 3.1) 22739:2020, 3.20) Asset (ISO 22739:2020,
3.14)
(Crypto-asset )
Token (ISO (Token) Fungibili- Fungible Token
(ISO 22739:2020,
22739:2020, 3.76) ty (Fungible (ISO
3.13)
Non-Fungible Token
23257:2021, 3.12)
[NFT]
Token Metadata Digital Asset De-
scription
Privilege Descrip-
tion
Value Description
(Asset) Prov- Origin of Asset
enance (ISO
History of Asset
23257:2021, 3.11)
History of Cus-
tody
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ISO/TS 23258:2021(E)
Table 1 (continued)

Level 1 concepts Level 2 concepts Level 3 concepts Level 4 concepts Level 5 concepts Level 6 concepts

Consensus (ISO Consensus Fault Tolerance Byzantine Fault Practical Byzan-
22739:2020, Mechanism (ISO Tolerance [BFT] tine Fault Toler-
3.11) 22739:2020, 3.12) ance [PBFT]
Crash Fault Toler-
ance
Nakamoto Con- Proof of Stake Delegated Proof of
sensus [PoS] Stake [DPoS]
Proof of Work
[PoW]
Consensus Secu-
rity
Smart Contract Legally Binding
(ISO 22739:2020, Smart Contract
3.72)
Entity (ISO Legal Entity Group
22739:2020,
3.34)
Organization Autonomous Or- Decentralized
ganization Autonomous Or-
ganization [DAO]
Person Operator Distributed
Ledger Technolo-
gy Operator [DLT
Operator]
User D i s t r i b u t e d
Ledger Technol-
ogy User (ISO
22739:2020, 3.31)
[DLT User (ISO
22739:2020, 3.31)]
Process Action Confirmation Block Confirma-
tion
Transaction Con-
firmation
Compliance
Deletion (Delete Transaction De-
ISO 23257:2021, 3.2) letion
Execution Execution of Con- Stateful Execution
tract of Contract
Stateless Execution
of Contract
Validation (ISO Block Validation
22739:2020, 3.82)
Ledger Record
Validation
Transaction Vali-
dation
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ISO/TS 23258:2021(E)
Table 1 (continued)

Level 1 concepts Level 2 concepts Level 3 concepts Level 4 concepts Level 5 concepts Level 6 concepts

Activity Archiving Data Archiving
(Archive ISO (ISO 23257:2021,
23257:2021, 3.3) 3.4)
Resource Archiv-
ing
Transaction Ar-
chiving
Hashing
Mining (ISO
22739:2020, 3.49)
Restoring Data Restoring
(Restore
Resource Restor-
ISO 23257:2021,
ing
3.6)
Transaction Re-
storing
Event Disruption (ISO Attack
23257:2021, 3.10)
Incident (ISO
23257:2021, 3.8)
Error Error analytics
Failure (ISO
22739:2020, 3.35)
Fault Fault Tolerance
(ISO 22739:2020,
3.36)
Fork (ISO Hard Fork (ISO
22739:2020, 3.45) 22739:2020, 3.38)
Soft Fork (ISO
22739:2020, 3.73)
Work Process Backup (ISO Data Backup
23257:2021, 3.5)
Resource Backup
Transaction
Backup
Transaction (ISO
22739:2020, 3.77)
Thing Object Device
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ISO/TS 23258:2021(E)
Table 1 (continued)

Level 1 concepts Level 2 concepts Level 3 concepts Level 4 concepts Level 5 concepts Level 6 concepts

Node (ISO Child Node
22739:2020, 3.50)
Distributed Miner (ISO
Ledger Tech- 22739:2020, 3.48)
nology Node
Participant
[DLT Node (ISO
Validator (ISO
22739:2020,
22739:2020, 3.83)
3.27)]
Leaf Node (ISO
22739:2020, 3.42)
Non-Leaf Node
Parent Node
Peer
Root Node (ISO (Node) Merkle Root
22739:2020, 3.69) (ISO 22739:2020,
3.46)
Platform Distributed
Ledger Tech-
nology Platform
[DLT Platform
(ISO 22739:2020,
3.29)]
Governance Control Decentralized
Control
Governance Rule
Incentive Incentive Reward System Block Reward
Mechanism (ISO (ISO 22739:2020, (ISO 22739:2020,
22739:2020, 3.68) 3.5)
3.68)
Interoperability Transport Inter-
(ISO 22739:2020, operability
3.41)
Syntactic Interop-
erability
Semantic Interop-
erability
Behavioral Inter-
operability
Policy Interoper-
ability
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ISO/TS 23258:2021(E)
Table 1 (continued)

Level 1 concepts Level 2 concepts Level 3 concepts Level 4 concepts Level 5 concepts Level 6 concepts

Ledger (ISO Distributed Blockchain (ISO
22739:2020, Ledger (ISO 22739:2020, 3.6)
3.43) 22739:2020, 3.22)
Distributed Ledg- Distributed
er Control Ledger Control
Architecture
Distributed Ledg-
er Privilege
Distributed
Ledger Pruning
(Prune (ISO
22739:2020, 3.63)
Distributed Ledg- Distributed
er Storage Ledger Storage
Architecture
Shared Ledger
(ISO 22739:2020,
3.70)
Ledger Implemen- Block (ISO Block Data (ISO
tation 22739:2020, 3.2) 22739:2020, 3.3)
Block Header (Block) Hash
(ISO 22739:2020, Value (ISO
3.4) 22739:2020, 3.39)
(Block) Merkle
Root
(Block) Nonce
(ISO 22739:2020,
3.51)
Block Number (or Genesis Block (ISO
Block Height) 22739:2020, 3.37)
Previous Block
(Block) Times-
tamp (ISO
22739:2020, 3.75)
Block Status Confirmed (ISO
22739:2020,
3.8) Block (ISO
22739:2020, 3.9)
Validated (ISO
22739:2020, 3.81)
Block
Ledger Status Inconsistent Double Spending
Ledger (ISO 22739:2020,
3.33)
Ledger Split (ISO
22739:2020, 3.45)
Ledger Tamper Tamper-Resistant
Resistance
Traditional Ledger
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ISO/TS 23258:2021(E)
Table 1 (continued)

Level 1 concepts Level 2 concepts Level 3 concepts Level 4 concepts Level 5 concepts Level 6 concepts

Permission Hybrid Permis-
sion
Permissioned Permissioned Permissioned Permissioned Pri-
(ISO 22739:2020, Distributed Blockchain vate Blockchain
3.57) Ledger
Permissioned
Public Blockchain
Permissioned Permissioned
DLT System Blockchain Sys-
(ISO 22739:2020, tem
3.58)
Permissionless Permissionless Permissionless Permissionless
(ISO 22739:2020, Distributed Blockchain Private Block-
3.59) Ledger chain
Permissionless
Public Blockchain
Permissionless Permissionless
DLT System (ISO Blockchain Sys-
22739:2020, 3.60) tem
Record (ISO Ledger Record (Ledger Record) Immutable
22739:2020, (ISO 22739:2020, Immutability
3.67) 3.44) (ISO 22739:2020,
3.40)
Ledger Record Validated (ISO
Status 22739:2020, 3.81)
Ledger Record
Transaction Transaction Fee
Record (ISO (ISO 22739:2020,
22739:2020, 3.79) 3.78)
(Transaction)
Hash Value (ISO
22739:2020, 3.39)
(Transaction)
Nonce (ISO
22739:2020, 3.51)
(Transaction)
Timestamp (ISO
22739:2020, 3.75)
Transaction Confirmed (ISO
Status 22739:2020, 3.8)
Transaction (ISO
22739:2020, 3.10)
Validated (ISO
22739:2020, 3.81)
Transaction
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ISO/TS 23258:2021(E)
Table 1 (continued)

Level 1 concepts Level 2 concepts Level 3 concepts Level 4 concepts Level 5 concepts Level 6 concepts

Security Authentication User Authentica- Password
tion
Authorization User Authoriza-
tions
Cryptography Asymmetric Public Key Cryp-
(ISO 22739:2020, Cryptography tography (ISO
3.17) 22739:2020, 3.66)
Cryptographic Cryptographic Hash Value (ISO
Technique Hash Function 22739:2020, 3.39)
(ISO 22739:2020,
3.15)
Cryptograph-
ic Link (ISO
22739:2020, 3.16)
Cryptographic Tree Data Struc- Merkle Tree (ISO
Tree ture 22739:2020, 3.47)
Digital Signature
(ISO 22739:2020,
3.21)
Encryption Key Private Key (ISO
22739:2020, 3.62)
Public Key (ISO
22739:2020, 3.65)
Decryption
Encryption
Identifiable Infor- Personally
mation Identifiable
Information [PII
(ISO 23257:2021,
3.1)]
Identity Manage- Identity Self-Sovereign
ment Identity [SSID]
Integrity Check Integrity
Privacy Manage-
ment
Service Application Decentralized
Application
[DApp (ISO
22739:2020,
3.18)]
Wallet (ISO Account Distributed
22739:2020, Ledger Technol-
3.84) ogy
Account [DLT
Account (ISO
22739:2020,
3.24)]
Address Distributed
Ledger Tech-
nology Address
[DLT Address
(ISO 22739:2020,
3.25)]
Hardware Wallet
Software Wallet
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ISO/TS 23258:2021(E)
Table 1 (continued)

Level 1 concepts Level 2 concepts Level 3 concepts Level 4 concepts Level 5 concepts Level 6 concepts

Cloud Service Blockchain as a
Service [BaaS]
Oracle Distributed
Ledger Tech-
nology Oracle
[DLT Oracle
(ISO 22739:2020,
3.28)]
System Decentralized
System (ISO
22739:2020, 3.19)
Distributed Distributed Blockchain Off-Chain (ISO
System (ISO Ledger System System (ISO 22739:2020, 3.52)
22739:2020, 3.32) [DLT System 22739:2020, 3.7)
On-Chain (ISO
(ISO 22739:2020,
22739:2020, 3.54)
3.30)]
Sidechain (ISO Associated Blockchain
22739:2020, 3.71) System
Main chain
Subchain (ISO
22739:2020, 3.74)
Off-Ledger (ISO
22739:2020, 3.53)
On-Ledger (ISO
22739:2020, 3.55)
Private Distrib-
uted Ledger
(Technology)
System [Private
DLT System
(ISO 22739:2020,
3.61)]
Public Distrib-
uted Ledger
(Technology)
System [Pub-
lic DLT System
(ISO 22739:2020,
3.64)]
Ecosystem Token Ecosystem
Subsystem Network Distributed
Ledger Technol-
ogy
Network [DLT
Network (ISO
22739:2020,
3.26)]
Peer-To-Peer
(ISO 22739:2020,
3.56) Network
(System) Re-
silience (ISO
23257:2021, 3.7)
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ISO/TS 23258:2021(E)
Table 1 (continued)

Level 1 concepts Level 2 concepts Level 3 concepts Level 4 concepts Level 5 concepts Level 6 concepts

Technology Information and
Communication
Technology [ICT
(ISO 23257:2021,
3.9)]
Ledger Technol- Distributed Blockchain Tech-
ogy Ledger Tech- nology
nology [DLT
(ISO 22739:2020,
3.23)]
Trust (ISO Product Confi-
22739:2020, dence
3.80)
Service Confi-
dence

Group can be a group of items including legal entity, person, process, thing according to ISO 22739:2020, 3.34.

DLT Node may be below Device or Process and was set below Object to avoid duplicate.

Non-cryptographic assets are not covered e.g. when token is considered as a subclass of cryptographic asset (or

crypto-asset), token refers to cryptographic token (or crypto-token).
5.3 Taxonomy of DLT systems
5.3.1 General

The taxonomy of DLT systems is based on several key aspects including whether it is permissioned or

permissionless, the type of consensus mechanism and the existence of incentive mechanisms. Such a

classification helps the companies and organizations to understand and differentiate DLT systems.

5.3.2 Major characteristics of DLT systems
5.3.2.1 General

To provide classification for DLT systems, it is required to analyse them into various categories based

on their similarities on different aspect through main characteristics. See Annex A for an example for

classification of DLT system based on the taxonomy of DLT systems.
5.3.2.2 Purpose of DLT system

DLT systems (including blockchain systems) are designed to implement tamper-resistant distributed

ledgers, using consensus for maintaining a ledger in a distributed network of DLT nodes. Incentives in

DLT systems can drive the achievement of consensus among decision makers, the resolution of conflicts

and the taking of decisions regarding the ongoing governance, design and operation of systems.

Business purpose of DLT systems defines the essential concepts associated with these systems. For

example, Bitcoin system is to allow people to store and transfer value securely and anonymously.

Therefore, the purpose of the Bitcoin system can be described as a payment.
5.3.2.3 Ledger design

Blockchain is one of the most popular ledger designs in the industry. However another systems might

apply a different type of ledger design like DAG (Directed Acyclic Graph) to commit their specific

requirements, for example, Internet of Things. In addition, new ledger designs might be continuously

inspired by developers of DLT system in the future.

Blockchain is a distributed ledger with confirmed blocks organized in an append-only, sequential chain

using cryptographic links. This distributed ledger forms a linear chain of blocks of transactions in an

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ISO/TS 23258:2021(E)

unalterable, chronological order. Transactions are bundled into blocks of transactions to be validated.

Validated blocks are added to a chain of previously validated blocks.

By comparison, a DAG is a network of individual transactions linked to multiple other transactions.

There are no blocks of transactions in DAG networks. If blockchain is a linked list, a DAG is a tree,

branching out from one transaction to another, to another and so on.

Blockchain offers transparency and immutability. It is also relatively well established, being the basis of

cryptocurrencies like Bitcoin and of distributed application (Dapp) platforms like Ethereum. Blockchain

offers solid guarantees and cost-effectiveness for transactions of medium to high value.

By scaling very efficiently and avoiding or reducing user fees, DAGs are well suited to high volumes of

transactions, including micro and nano-transactions. The higher the volume of transactions, the faster

a DAG validates them. DAGs also cut out the need for miners and in turn mining equipment — meaning

lower energy consumption.
5.3.2.4 DLT system permission
5.3.2.4.1 General

According to whether it is requiring permissions to use or operate the system, the types of DLT systems

can be classified as permissionless and permissioned DLT systems.

A permissionless DLT system doesn’t require any permission in order to use the system as a DLT user

or to participate in operation of the system as a DLT node. By contrast a permissioned DLT system does

require some permissions in order to perform a particular activity or activities.

5.3.2.4.2 Permissioned DLT system

In a permissioned DLT system, permissions are required for some capabilities to use the system or

permissions are required for some capabilities to operate the system. Therefore, any participant who

wants to use the system or join to run the DLT network needs to request and get an approval from the

host of the system before they access and use the permissioned DLT system.

In the aspect of operating the system, all DLT nodes of permissioned DLT system are authorized to join

the network and participate in the consensus process to build the blockchain or distributed ledger. In

such system, there might be a central authority which determines and controls the permission for a DLT

node to join the network as well as restricts the DLT nodes on which can participate in the consensus

process to validate block transactions and propose blocks.

In the aspect of DLT user, permissioned DLT system can restrict access for DLT users who use services

provided by DLT system. In such system, all the users should have a permission to use the DLT system.

A permissioned blockchain only allows users who have permissions to read block information and to

create smart contracts interacted with the ledger.
5.3.2.4.3 Permissionless DLT system

Permissionless DLT system allow any entity to participate in the system, and there is no authentication

or authorization required to access and use the system. Therefore, any participant in the permissionless

DLT system is anonymous and there is no way to restrict anyone in such system.
In permissionless
...

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