ISO/IEC 24760-1:2025

International
Standard
ISO/IEC 24760-1
Third edition
Information security, cybersecurity
2025-09
and privacy protection —
A framework for identity
management —
Part 1:
Core concepts and terminology
Sécurité de l'information, cybersécurité et protection de la vie
privée — Cadre pour la gestion de l'identité —
Partie 1: Concepts fondamentaux et terminologie
Horizontal document
Reference number
© ISO/IEC 2025
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
© ISO/IEC 2025 – All rights reserved
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
3.1 General terms .1
3.2 Identification .3
3.3 Authenticating identity information .3
3.4 Management of identity .6
3.5 Federation .8
3.6 Privacy protection .8
4 Symbols and abbreviated terms. 9
5 Identity . 9
5.1 General .9
5.2 Identity information .10
5.3 Identifier .11
5.4 Credential .11
5.4.1 General .11
5.4.2 Authenticator. 12
5.4.3 Credential management . 13
6 Attributes .13
6.1 General . 13
6.2 Types of attributes . 13
6.3 Domain of origin .14
7 Managing identity information .15
7.1 General . 15
7.2 Identity lifecycle . 15
8 Identification . 17
8.1 General .17
8.2 Verification . .18
8.3 Enrolment .18
8.4 Registration .18
8.5 Identity proofing .19
8.5.1 General .19
8.5.2 Identity evidence .19
9 Authentication .20
10 Maintenance .20
11 Implementation aspects .20
12 Privacy .21
Bibliography .22
Index of terms . .24

© ISO/IEC 2025 – All rights reserved
iii
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).
ISO and IEC draw attention to the possibility that the implementation of this document may involve the
use of (a) patent(s). ISO and IEC take 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 and IEC had not
received notice of (a) patent(s) which may be required to implement this document. However, implementers
are cautioned that this may not represent the latest information, which may be obtained from the patent
database available at www.iso.org/patents and https://patents.iec.ch. ISO and IEC shall not be held
responsible for identifying any or all such patent rights.
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 Technical Committee ISO/IEC JTC 1, Information technology, Subcommittee
SC 27, Information security, cybersecurity and privacy protection.
This third edition cancels and replaces the second edition (ISO/IEC 24760-1:2019), which has been
technically revised. It also incorporates the Amendment ISO/IEC 24760-1:2019/Amd 1:2023.
The main changes are as follows:
— title has been updated;
— the document has been editorially revised.
A list of all parts in the ISO/IEC 24760 series can be found on the ISO website.
This document has been given the status of a horizontal document in accordance with the ISO/IEC
Directives, Part 1.
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.

© ISO/IEC 2025 – All rights reserved
iv
Introduction
Data processing systems commonly gather a range of information on their users, be it a person, piece of
equipment, or piece of software connected to them, and make decisions based on the gathered information.
Such identity-based decisions can concern access to applications or other resources.
To address the need to efficiently and effectively implement systems that make identity-based decisions, the
ISO/IEC 24760 series specifies a framework for the issuance, administration, and use of data that serves to
characterize individuals, organizations or information technology components which operate on behalf of
individuals or organizations.
For many organizations, the proper management of identity information is crucial for maintaining security
within organizational processes. For individuals, correct identity management is important for protecting
privacy.
The ISO/IEC 24760 series specifies fundamental concepts and operational structures for identity
management and provides a framework on which information systems can meet business, contractual,
regulatory, and legal obligations.
This document specifies the terminology and concepts for identity management, in order to promote a
common understanding in the field of identity management.
This document is intended to provide a foundation for the terminology and concepts in other international
standards related to identity information processing including other parts of the ISO/IEC 24760 series,
ISO/IEC 29100, ISO/IEC 29101, ISO/IEC 29115, and ISO/IEC 29146.

© ISO/IEC 2025 – All rights reserved
v
International Standard ISO/IEC 24760-1:2025(en)
Information security, cybersecurity and privacy protection —
A framework for identity management —
Part 1:
Core concepts and terminology
1 Scope
This document:
— defines terms for identity management and specifies core concepts of identity and identity management,
and their relationships;
— is applicable to any information system where information relating to identity is processed or stored;
— is considered to be a horizontal document for the following reasons:
— it applies concepts such as distinguishing the term “identity” from the term “identifier” on the
implementation of systems for the management of identity information and on the requirements for
the implementation and operation of a framework for identity management,
— it provides an important contribution to assess identity management systems with regard to their
privacy-friendliness and their ability to assure the relevant attributes of an identity, and consequently
it provides a foundation and a common understanding for any other standard addressing identity,
identity information, and identity management.
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 24760-2, Information security, cybersecurity and privacy protection — A framework for identity
management — Part 2: Reference architecture and requirements
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 General terms
3.1.1
entity
item relevant for the purpose of operation of a domain (3.2.3) that has recognizably distinct existence
Note 1 to entry: An entity can have a physical or a logical embodiment.

© ISO/IEC 2025 – All rights reserved
EXAMPLE A person, an organization, a device, a group of such items, a human subscriber to a telecom service, a
SIM card, a passport, a network interface card, a software application, a service or a website.
3.1.2
identity
partial identity
set of attributes (3.1.3) related to an entity (3.1.1)
Note 1 to entry: An entity can have more than one identity.
Note 2 to entry: Several entities can have the same identity.
Note 3 to entry: ITU-T X1252 specifies the distinguishing use of an identity. In this document, the term identifier (3.1.4)
implies this aspect.
3.1.3
attribute
characteristic or property of an entity (3.1.1)
EXAMPLE An entity type, address information, telephone number, a privilege, a MAC address, a domain name are
possible attributes.
3.1.4
identifier
attribute (3.1.3) or set of attributes that uniquely characterizes an identity (3.1.2) in a domain (3.2.3)
Note 1 to entry: An identifier can be a specifically created attribute with a value assigned to be unique within the domain.
EXAMPLE A name of a club with a club-membership number, a health insurance card number together with a
name of the insurance company, an email address, or a universal unique identifier (UUID) can all be used as identifiers.
In a voter’s register, the combination of attributes name, address and date of birth is sufficient to unambiguously
distinguish a voter.
3.1.5
domain of origin
domain (3.2.3) where an attribute (3.1.3) value was created or its value has been (re)assigned
Note 1 to entry: The domain of origin can be provided as meta data for an attribute.
Note 2 to entry: The domain of origin typically specifies the meaning and format of the attribute value. Such
specification can be based on international standards.
Note 3 to entry: An attribute can contain an explicit value that references the domain of origin, e.g. an ISO country
code for a passport number as reference to the issuing country that is the domain of origin of identity information
(3.2.4) in the passport.
Note 4 to entry: Operationally, a domain of origin can be available as an authoritative source for an attribute
(sometimes known as the attribute authority). An authoritative source can be operated outside the actual domain of
origin. Multiple authoritative sources can exist for the same domain of origin.
EXAMPLE The domain of origin of a club-membership number is the specific club that assigned the number.
3.1.6
reference identifier
RI
identifier (3.1.4) in a domain (3.2.3) that is intended to remain the same for the duration an entity (3.1.1) is
known in the domain and is not associated with another entity for a period specified in a policy after the
entity ceases to be known in that domain
Note 1 to entry: A reference identifier persists at least for the existence of the entity in a domain and can exist longer
than the entity, e.g. for archival purposes.
Note 2 to entry: A reference identifier for an entity can change during the lifetime of an entity, at which point the old
reference identifier is no longer applicable for that entity.

© ISO/IEC 2025 – All rights reserved
EXAMPLE A driver license number that stays the same for an individual driver’s driving life is a persistent
identifier, which references additional identity information (3.2.4) and that is a reference identifier. An IP address is
not a reference identifier as it can be assigned to other entities.
3.1.7
principal
subject
entity (3.1.1) of which identity information (3.2.4) is stored and managed by an identity management system (3.4.8)
Note 1 to entry: Typically, in a context of privacy protection or where a principal is seen as having agency a principal
refers to a person.
3.2 Identification
3.2.1
identification
process of recognizing an entity (3.1.1) in a particular domain (3.2.3) as distinct from other entities
Note 1 to entry: The process of identification applies verification to claimed or observed attributes.
Note 2 to entry: Identification typically is part of the interactions between an entity and the services in a domain and
to access resources. Identification can occur multiple times while the entity is known in the domain.
3.2.2
verification
process of establishing that identity information (3.2.4) associated with a particular entity (3.1.1) is correct
Note 1 to entry: Verification typically involves determining which attributes are needed to recognize an entity in a
domain (3.2.3), checking that these required attributes are present, that they have the correct syntax, and exist within
a defined validity period and pertain to the entity.
3.2.3
domain
domain of applicability
context
environment where an entity (3.1.1) can use a set of attributes (3.1.3) for identification (3.2.1) and other
purposes
Note 1 to entry: In general, the domain of an identity (3.1.2) is well defined in relation to the particular set of attributes.
Note 2 to entry: ITU-T X1252 uses the term context; this document prefers the term domain.
EXAMPLE An IT system deployed by an organization that allows users to login is the domain for the user’s login name.
3.2.4
identity information
set of values of attributes (3.1.3) optionally with any associated metadata in an identity (3.1.2)
Note 1 to entry: In an information and communication technology system, an identity is present as identity information.
3.3 Authenticating identity information
3.3.1
authentication
formalized process of verification (3.2.2) that, if successful, results in an authenticated identity (3.3.2) for an
entity (3.1.1)
Note 1 to entry: The authentication process involves tests by a verifier of one or more identity attributes provided by
an entity to determine, with the required level of assurance, their correctness.
Note 2 to entry: Authentication typically involves the use of a policy to specify a required level of assurance for the
result of a successful completion.

© ISO/IEC 2025 – All rights reserved
3.3.2
authenticated identity
identity information (3.2.4) for an entity (3.1.1) created to record the result of authentication (3.3.1)
Note 1 to entry: An authenticated identity typically contains information obtained in the authentication process, e.g.
the level of assurance attained.
Note 2 to entry: The existence of an authenticated identity in a particular domain denotes that an entity has been
recognized in that domain.
Note 3 to entry: An authenticated identity typically has a lifespan restricted by an authentication policy.
3.3.3
identity information authority
IIA
entity (3.1.1) related to a particular domain (3.2.3) that can make provable statements on the validity and/or
correctness of one or more attribute (3.1.3) values in an identity (3.1.2)
Note 1 to entry: An identity information authority is typically associated with the domain, for instance the domain of
origin (3.1.5), in which the attributes, which the IIA can make assertions on, have a particular significance.
Note 2 to entry: The activity of an identity information authority can be subject to a policy on privacy protection.
Note 3 to entry: An entity can combine the functions of identity information provider (3.3.4) and identity information
authority.
3.3.4
identity information provider
IIP
identity provider
entity (3.1.1) that makes available identity information (3.2.4)
Note 1 to entry: Typical operations performed by an identity information provider are to create and maintain identity
information for entities known in a particular domain. An identity information provider and an identity information
authority (3.3.3) can be the same entity.
3.3.5
credential
representation of an identity (3.1.2) for use in authentication (3.3.1)
Note 1 to entry: As described in 5.4, customary embodiments of a credential are very diverse. To accommodate this
wide range, the definition adopted in this document is very generic.
Note 2 to entry: A credential is typically made to facilitate data authentication of the identity information (3.2.4)
pertaining to the identity it represents. Data authentication is typically used in authorization.
Note 3 to entry: The identity information represented by a credential can, for example, be printed on human-readable
media, or stored within a physical token. Typically, such information can be presented in a manner designed to
reinforce its perceived validity.
EXAMPLE A credential can be a username, username with a password, a PIN, a smartcard, a token, a fingerprint,
a passport, etc.
3.3.6
verifier
entity (3.1.1) that performs verification (3.2.2)
Note 1 to entry: A verifier can be the same as, or act on behalf of, the entity that controls identification of entities for a
particular domain.
© ISO/IEC 2025 – All rights reserved
3.3.7
relying party
RP
entity (3.1.1) that relies on the verification (3.2.2) of identity information (3.2.4) for a particular entity
Note 1 to entry: A relying party is exposed to risk caused by incorrect identity information. Typically, it has a trust
relationship with one or more identity information authorities (3.3.3).
3.3.8
identity assertion
statement by an identity information authority (3.3.3) used by a relying party (3.3.7) for authentication (3.3.1)
Note 1 to entry: An identity assertion can be the cryptographic proof of a successful authentication, created with
algorithms and keys agreed between parties, e.g. in an identity federation.
3.3.9
authentication factor
distinguishing feature of an authenticator to characterize its use in authentication (3.3.1)
Note 1 to entry: Four different authentication factors can be recognized:
— cognition factor, any credential (3.3.5) that is formed by something that the principal (3.1.7) knows and can
reproduce (exclusively): a personal secret (3.3.13);
— possession factor, any credential that is formed by something that the principal possesses, e.g. an authenticator;
— inherent factor, any credential that is formed by a description of something that is inherent to the physical existence
of the principal, e.g. a biometric characteristic such as fingerprint, facial image, or 1, iris pattern;
— behaviour factor, any credential that is formed by a description of something that the principal typically does, e.g.
a behaviour pattern.
3.3.10
multi-factor authentication
authentication (3.3.1) in which multiple authenticators (3.3.11) are used of two or more authentication
factors (3.3.9)
Note 1 to entry: If two or more authenticators are being used in authentication that have the same authentication
factor, they should have been issued by different credential issuers (3.4.10).
Note 2 to entry: Using multiple authenticators that differ in authentication factor can enhance the security of the
authentication as that could prompt the principal (3.1.7) to act differently with each of them.
1)
[SOURCE: ISO/IEC 19790:2012, 3.74, modified — definition and notes to entry have been updated to align
with the context of this document.]
3.3.11
authenticator
representation of an entity (3.1.1) to demonstrate it is known in a domain of origin (3.1.5)
EXAMPLE One-time password (OTP) generator token, transaction authentication number (TAN) generator token,
an electronic (identity) card or a mobile phone application with one or more of these functions.
Note 1 to entry: An authenticator can have a physical form, which can be under exclusive operational control of a
principal (3.1.7).
Note 2 to entry: As a physical device an authenticator can provide a cryptographically strong identifier for the
principal, which can be a pseudonym or ephemeral (3.6.4).
Note 3 to entry: An authenticator is intended to be used by the principal to provide input on its behalf during
authentication (3.3.1) functioning as a possession factor.
1) Cancelled and replaced by ISO/IEC 19790:2025.

© ISO/IEC 2025 – All rights reserved
Note 4 to entry: An authenticator can be provided to a principal by a credential issuer (3.4.10) which is unrelated to
the domain of origin. Upon enrolment in a domain of origin of a principal who has such a third-party authenticator, the
(pseudonymous) identifier of the authenticator is typically recorded as attribute for the principal.
Note 5 to entry: An authenticator can either be unconnected, or connected through a computer interface, e.g. a USB
port, or can be integrated with a user device, e.g. as application in a smart phone. As a mobile application it could use a
secure element in the phone to protect cryptographic secrets or a personal secret (3.3.13).
Note 6 to entry: While under operational control of the principal, an authenticator can also be under secure, remote
functional control of its issuer, e.g. to update functional parameters or refresh cryptographic keys.
3.3.12
one-time password
OTP
single-use value randomly generated for use in authentication (3.3.1)
Note 1 to entry: An authenticator may be configured to generate a one-time password, typically after its operator has
entered a personal secret (3.3.13).
3.3.13
personal secret
knowledge exclusive to a principal (3.1.7) that can be validated in a domain of origin (3.1.5) where the
principal is known
EXAMPLE A password, PIN, selecting pictures from a presented randomized grid with a type of content pre-
arranged with the credential issuer (3.4.10).
Note 1 to entry: Each different type of personal secret has an establishment procedure implemented by the credential
issuer to provide an associated identity information authority (3.3.3) with the information required for future
validation.
Note 2 to entry: Each different type of personal secret has a verification (3.2.2) procedure implemented by the identity
information authority associated with the credential issuer to verify that knowledge based on securely stored
information.
Note 3 to entry: In general, data communication during the process to establish or validate a personal secret as a
credential (3.3.5) is cryptographically protected, e.g. with HTTPS.
3.4 Management of identity
3.4.1
identity management
IDM
processes and policies involved in managing the lifecycle and value, type and optional metadata of attributes
(3.1.3) in identities (3.1.2) known in a particular domain (3.2.3)
Note 1 to entry: In general, identity management is involved in interactions between parties where identity information
(3.2.4) is processed.
Note 2 to entry: Processes and policies in identity management support the functions of an identity information
authority (3.3.3) where applicable, in particular to handle the interaction between an entity for which an identity is
managed and the identity information authority.
3.4.2
identity proofing
initial entity authentication
verification (3.2.2) based on identity evidence (3.4.4) aimed at achieving a specific level of assurance
Note 1 to entry: Identity proofing is typically performed as part of enrolment (3.4.3). Identity evidence can also be
needed during maintenance of registered identity information, e.g. recovery of a user account.
Note 2 to entry: Typically, identity proofing involves a verification of provided identity information and can include
uniqueness checks, possibly based on biometric techniques.

© ISO/IEC 2025 – All rights reserved
Note 3 to entry: Verification for identity proofing is usually based on an enrolment policy that includes specification of
the verification criteria of the identity evidence to be provided by the entity.
Note 4 to entry: The verified identity information (3.2.4) obtained when performing identity proofing can be included
in the registration and can serve to facilitate future identification of the entity (3.1.1).
3.4.3
enrolment
process to make an entity (3.1.1) known within a particular domain (3.2.3)
Note 1 to entry: Enrolment typically comprises the collection and validation of identity information (3.2.4) for
identification of an entity and the collection of the identity information (3.2.4) required for identity registration (3.4.6),
followed by identity registration itself.
3.4.4
identity evidence
evidence of identity
information that can support validating identity information (3.2.4)
Note 1 to entry: Identity evidence is the presented and gathered information related to an entity that provides the
attributes (3.1.3) needed for a successful identification or authentication (3.3.1) at a specific (high) level of assurance.
3.4.5
identity register
IMS register
repository of identities (3.1.2)
Note 1 to entry: A typical identity register is indexed by a reference identifier.
Note 2 to entry: The identity information authority (3.3.3) in a particular domain (3.2.3) typically uses its own identity
register. However, an identity register can be shared between related domains, e.g. within the same commercial entity.
Note 3 to entry: The reliability of the identity information (3.2.4) in an identity register is determined by the identity
proofing policies used during enrolment (3.4.3).
3.4.6
identity registration
registration
process of recording an entity’s (3.1.1)identity information (3.2.4) in an identity register (3.4.5)
3.4.7
identity management system
mechanism comprising of policies, procedures, technology and other resources for maintaining identity
information (3.2.4) including associated metadata
Note 1 to entry: An identity management system is typically used for identification (3.2.1) or authentication (3.3.1)
of entities. It can be deployed to support other automated decisions based on identity information for an entity
recognized in the domain for the identity management system.
3.4.8
registration authority
RA
entity (3.1.1) related to a particular domain (3.2.3) responsible for enrolment (3.4.3), identity proofing (3.4.2)
and identity registration (3.4.6)
3.4.9
credential issuer
entity (3.1.1) responsible for provisioning of a credential (3.3.5) to a principal (3.1.7) in a specific domain (3.2.3)
Note 1 to entry: A credential provisioned by a credential issuer can have a physical form, e.g. a membership (smart) card.
Note 2 to entry: The issuance of a credential for a principal can be recorded as an attribute (3.1.3) for the principal, e.g.
by recording the unique number of the token issued.

© ISO/IEC 2025 – All rights reserved
Note 3 to entry: A credential provisioned by an issuer can be a username and password. A credential in the form of a
smart card or similar security device, can be configured to validate a password off-line.
3.4.10
entity authentication assurance
assertion that the reliability of identity information (3.2.4) pertains to a particular entity
3.4.11
level of assurance
description of the strength of entity authentication assurance
Note 1 to entry: ISO/IEC 29115:2013 specifies multiple levels of assurance.
3.4.12
principal’s personal identity management system
PPI
mobile identity
identity management system (3.4.8) holding identity information (3.2.4) for a single principal (3.1.7), operated
by, or under exclusive control of, this principal
Note 1 to entry: The term “mobile identity” has been used, among other concepts, to refer to a PPI, e.g. as implemented
on a mobile phone or as a dedicated processing token.
Note 2 to entry: An authenticator can be configured to operate as private IMS for its principal. In that case, some
attributes in the identity are exclusively stored in the authenticator, while an external identity information provider
(3.3.4) may be used for additional attributes, and an external identity information authority may be used to provide
(additional) cryptographic assertions on the contained identity information.
3.5 Federation
3.5.1
identity federation
agreement between two or more domains (3.2.3) specifying how identity information (3.2.4) will be
exchanged and managed for cross-domain identification (3.2.1) purposes
Note 1 to entry: Establishing an identity federation typically includes an agreement on the use of common protocols
and procedures for privacy control, data protection and auditing. The federation agreement can specify the use of
standardized data formats and cryptographic techniques.
Note 2 to entry: The federation agreement can be the basis for identity authorities in each of the domains of
applicability to mutually recognize credentials for authorization.
3.6 Privacy protection
3.6.1
selective disclosure
principle of identity management (3.4.1) that gives a person a measure of control over the identity information
(3.2.4) that can be transferred to a third party, e.g. during authentication (3.3.1)
Note 1 to entry: In jurisdictions where certain types of legal entities are granted the right of privacy protection, the
term "person" should be interpreted to include such entities, otherwise the term "person" is used in relation to a single
human individual.
3.6.2
minimal disclosure
principle of identity management (3.4.1) to restrict the request or transfer of identity information (3.2.4) to a
third party to the minimum information strictly required for a particular purpose
Note 1 to entry: The principle of proportionality is related to minimal disclosure in so far as the effort of control
intervention is reasonable in relation to the activity.

© ISO/IEC 2025 – All rights reserved
3.6.3
pseudonym
identifier (3.1.4) that contains the minimal identity information (3.2.4) sufficient to allow a verifier (3.3.6) to
establish it as a link to a known identity (3.1.2)
Note 1 to entry: A pseudonym can be used to reduce privacy risks that are associated with the use of identifiers with
fixed or known values.
Note 2 to entry: A pseudonym can be an identifier with a value chosen by the person or assigned randomly.
Note 3 to entry: In jurisdictions where certain types of legal entities are granted the right of privacy protection, the
term "person" should be interpreted to include such entities, otherwise the term "person" is used in relation to a single
human individual.
3.6.4
ephemeral identifier
identifier (3.1.4) with a restricted validity period
Note 1 to entry: Typically, an ephemeral identifier is provided to a subject as a cryptographic credential to represent
an authenticated identity (3.3.2).
Note 2 to entry: Typically, an ephemeral identifier can only be verified in the domain (3.2.3) that created it, possibly
also in domains federated with this domain.
4 Symbols and abbreviated terms
HTTPS Hypertext transport protocol, secured
MAC Media access control
ICT Information and communication technology
URI Uniform resource identifier
5 Identity
5.1 General
An identity represents an entity in an ICT system as data to be stored or processed. The (business) purposes
of a particular domain of application served by an ICT system determine which of the attributes pertaining
to an entity shall be used in its identity. A persistently stored identity is the basis for identification of a
principal. If a persistent identity is not an identifier, identification can require additional information from
the principal.
An identity can, in part or fully, be represented by a credential issued to the principal. If an identity is
represented by such a credential, an identifier for the credential can be included in the registered identity.
This document considers any set of attributes that describe a particular entity as an identity for the entity.
In some domains, the persistently stored identity information for different entities can be the same. In this
case, additional information is used in identification to recognize an entity as distinct, where needed. In
[15]
other standards, e.g. ITU-T X1252, the explicit purpose of an identity is the capability of the identity
information to distinguish entities from each other to the extent relevant for applications in a domain (“in
context”).
An entity can have multiple identities, each identity relating to at least one domain. An entity can have
multiple identities relating to the same domain. Some identities of an entity cannot be unique in any domain.
NOTE 1 The term entity is taken in a broad sense. It represents a physical person, a moral or legal person
(institution, company), an object (information, a system, a device), or a group of these individual entities.

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NOTE 2 A human is an entity in this document and has a single, whole existence. It can be described by many
different attributes. Different sets of these attributes form different identities for the same human entity.
If an identity is not unique in a particular domain, it can serve to distinguish a group of entities in that
domain that share one or more characteristics from other entities that do not have such a characteristic.
The identity of an entity serves to make known relevant information of the entity in its interactions with the
services and access of resources provided by a domain. A domain specifies the type and range of permissible
values of attributes to be used for identification or other purposes.
NOTE 3 In some cases the term “partial identity” can be used to refer to a particular set of attributes taken from a
larger set of attributes, which in contrast can be referred to as the full identity — all available attributes — of an entity
in a domain. The preferred term in this document is identity.
A domain should deploy an identity management system conforming to the ISO/IEC 24760 series to manage
the identity information of the entities it intends to recognize.
5.2 Identity information
Information pertaining to a particular entity in a domain is called identity information.
If given identity information sufficiently distinguishes an entity from others in the context of a given use
case, then this identity information is a distinguishing identity.
If the combination of values contained in identity information is unique in the domain, then this identity
information is an identifier of the entity.
When a new identity is created for an entity in a domain, an identity information provider for the domain
can create values for required attributes of the new identity. The new attributes can consist of:
— any information required to facilitate the interaction between the domain and the entity for which the
identity is created;
— any information required for future identification of the entity, including description of aspects of the
physical existence of the entity;
— any information required for future authentication of the entity’s identity; or
— one or more reference identifiers.
The new identity information can be derived from identity information for the entity created in the current
or another domain. Deriving information can involve copying, collating, or
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