ISO/IEC 24745:2022

INTERNATIONAL ISO/IEC
STANDARD 24745
Second edition
2022-02
Information security, cybersecurity
and privacy protection — Biometric
information protection
Securité de l'information, cybersécurité et protection de la vie
privée — Protection des informations biométriques
Reference number
© ISO/IEC 2022
© ISO/IEC 2022
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
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© ISO/IEC 2022 – All rights reserved

Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms . 6
5 Biometric systems . 7
5.1 General . 7
5.2 Biometric system operations . 9
5.3 Biometric references and identity references (IRs) . 11
5.4 Biometric systems and identity management systems . 11
5.5 Personally identifiable information (PII) and privacy .12
5.6 Societal considerations . 12
6 Security aspects of a biometric system .13
6.1 Security requirements for biometric systems to protect biometric information .13
6.1.1 Confidentiality .13
6.1.2 Integrity .13
6.1.3 Renewability and revocability . 13
6.1.4 Availability . 14
6.2 Security threats and countermeasures in biometric systems . 14
6.2.1 Threats and countermeasures against biometric system components . 14
6.2.2 Threats and countermeasures during the transmission of biometric
information . 16
6.2.3 Renewable biometric references as countermeasure technology . 17
6.3 Security of data records containing biometric information . 19
6.3.1 Security for biometric information processing in a single database . 19
6.3.2 Security for biometric information processing in separated databases . 21
7 Biometric information privacy management .22
7.1 Biometric information privacy threats . 22
7.2 Biometric information privacy requirements and guidelines .22
7.2.1 Irreversibility . 22
7.2.2 Unlinkability .23
7.2.3 Confidentiality .23
7.3 Biometric information lifecycle privacy management . 23
7.3.1 Collection .23
7.3.2 Transfer (disclosure of information to a third party) . 24
7.3.3 Use . 24
7.3.4 Storage . 24
7.3.5 Retention . 25
7.3.6 Archiving and data backup . 25
7.3.7 Disposal . 25
7.4 Responsibilities of a biometric system owner . 25
8 Biometric system application models and security .26
8.1 Biometric system application models . 26
8.2 Security in each biometric application model . 27
8.2.1 General . 27
8.2.2 Model A — Store on server and compare on server.28
8.2.3 Model B — Store on token and compare on server.29
8.2.4 Model C — Store on server and compare on client . 31
8.2.5 Model D — Store on client and compare on client . 32
8.2.6 Model E — Store on token and compare on client .34
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© ISO/IEC 2022 – All rights reserved

8.2.7 Model F — Store on token and compare on token .36
8.2.8 Model G — Store distributed on token and server, compare on server . 37
8.2.9 Model H — Store distributed on token and client, compare on client .38
8.2.10 Model I — Store on server, compare distributed .40
8.2.11 Model J — Store on token, compare distributed . 41
8.2.12 Model K — Store distributed, compare distributed . 43
Annex A (informative) Secure binding and use of separated DB and DB .45
IR BR
Annex B (informative) Framework for renewable biometric references (RBRs) .48
Annex C (informative) Technology examples for biometric information protection .52
Annex D (informative) Biometric watermarking .54
Annex E (informative) Biometric information protection using information splitting .56
Annex F (informative) Selection of biometric application models .58
Bibliography .61
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Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are
members of ISO or IEC participate in the development of International Standards through technical
committees established by the respective organization to deal with particular fields of technical
activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international
organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the
work.
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 document 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 or
www.iec.ch/members_experts/refdocs).
Attention is drawn to the possibility that some of the elements of this document may be the subject
of patent rights. ISO and IEC 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) or the IEC
list of patent declarations received (see patents.iec.ch).
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. In the IEC, see www.iec.ch/understanding-standards.
This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 27, Information security, cybersecurity and privacy protection.
This second edition cancels and replaces the first edition (ISO/IEC 24745:2011), which has been
technically revised.
The main changes compared to the previous edition are as follows:
— correction of terms;
— removal of non-compliant requirements related to jurisdictions;
— clarification of various explanations;
— improvements on the requirements for protection of biometric information, with more explicit
enforcement of irreversibility and unlinkability;
— addition of relevant references to ISO/IEC 30136:2018;
— introduction of new application models based on recent technologies;
— addition of examples in annexes.
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 and
www.iec.ch/national-committees.
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© ISO/IEC 2022 – All rights reserved

Introduction
As the Internet becomes a more pervasive part of daily life, various services are bein
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