ISO 22600-2:2014

Health informatics — Privilege management and access control — Part 2: Formal models

ISO 22600 defines principles and specifies services needed for managing privileges and access control to data and/or functions. It focuses on communication and use of health information distributed across policy domain boundaries. This includes healthcare information sharing across unaffiliated providers of healthcare, healthcare organizations, health insurance companies, their patients, staff members, and trading partners by both individuals and application systems ranging from a local situation to a regional or even national situation. It specifies the necessary component-based concepts and is intended to support their technical implementation. It will not specify the use of these concepts in particular clinical process pathways. ISO 22600-2:2014 introduces the underlying paradigm of formal high-level models for architectural components. It is based on ISO/IEC 10746 (all parts) and introduces the domain model, the document model, the policy model, the role model, the authorization model, the delegation model, the control model, and the access control model.

Informatique de santé — Gestion de privilèges et contrôle d'accès — Partie 2: Modèles formels

L'ISO 22600 définit les principes de gestion des privilèges et de contrôle d'accès aux données et/ou aux fonctions et spécifie les services nécessaires à ces activités. Elle se concentre sur la communication et l'utilisation des informations de santé distribuées au-delà des limites d'un domaine de politique. Cela inclut le partage d'informations de santé entre professionnels de santé non affiliés, établissements de santé, sociétés d'assurance-maladie, patients, membres du personnel et partenaires commerciaux, par des individus tout comme par des systèmes d'application utilisés dans un contexte local, voire régional ou même national. Elle spécifie les concepts nécessaires pour chaque composante et est destinée à faciliter leur mise en oeuvre technique. Elle ne spécifiera pas l'utilisation de ces concepts pour des cheminements de processus cliniques particuliers. L'ISO 22600-2:2014 constitue une introduction au paradigme sous-jacent de modèles formels de haut niveau pour les composantes architecturales. Elle est basée sur l'ISO/IEC 10746 (toutes les parties) et introduit le modèle de domaine, le modèle de document, le modèle de politique, le modèle de rôle, le modèle d'autorisation, le modèle de délégation, le modèle de contrôle et le modèle de contrôle d'accès.

General Information

• Status: Published
• Publication Date: 21-Sep-2014
• ICS: 35.240.80 - IT applications in health care technology
• Technical Committee: ISO/TC 215 - Health informatics
• Drafting Committee: ISO/TC 215/WG 4 - Security, Safety and Privacy
• Current Stage: 9093 - International Standard confirmed
• Completion Date: 02-Jul-2020

Relations

• Revises: ISO/TS 22600-2:2006 - Health informatics — Privilege management and access control — Part 2: Formal models
• Effective Date: 25-Aug-2012

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 22600-2
First edition
2014-10-01
Health informatics — Privilege
management and access control —
Part 2:
Formal models
Informatique de santé — Gestion de privilèges et contrôle d’accès —
Partie 2: Modèles formels
Reference number
ISO 22600-2:2014(E)
©
ISO 2014

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ISO 22600-2:2014(E)

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© ISO 2014
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
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ISO 22600-2:2014(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms . 6
5 Component paradigm . 6
6 Generic models . 7
6.1 Framework . 7
6.2 Domain model . 9
6.3 Document model .10
6.4 Policy model .11
6.5 Role model .14
6.6 Authorization model — Role and privilege assignment .14
6.7 Control model .15
6.8 Delegation model .16
6.9 Access control model .18
Annex A (informative) Functional and structural roles .20
Bibliography .25
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ISO 22600-2:2014(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 on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 215, Health informatics.
This first edition of ISO 22600-2 cancels and replaces ISO/TS 22600-2:2006, which has been technically
revised.
ISO 22600 consists of the following parts, under the general title Health informatics — Privilege
management and access control:
— Part 1: Overview and policy management
— Part 2: Formal models
— Part 3: Implementations
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ISO 22600-2:2014(E)

Introduction
The distributed architecture of shared care information systems supporting service-oriented
architecture (SOA) is increasingly based on corporate networks and virtual private networks. For
meeting the interoperability challenge, the use of standardized user interfaces, tools, and protocols,
which ensures platform independence, but also the number of really open information systems, is
rapidly growing during the last couple of years.
As a common situation today, hospitals are supported by several vendors providing different applications,
which are not able to communicate authentication and authorization since each has its own way of
handling these functions. For achieving an integrated scenario, it takes a remarkable amount of money,
time, and efforts to get users and changing organizational environments dynamically mapped before
starting communication and cooperation. Resources required for the development and maintenance
of security functions grow exponentially with the number of applications, with the complexity of
organizations towards a regional, national, or even international level, and with the flexibility of users
playing multiple roles, sometimes even simultaneously.
The situation becomes even more challenging when inter-organizational communications happens,
thereby crossing security policy domain boundaries. Moving from one healthcare centre to another or
from country to country, different rules for privileges and their management can apply to similar types
of users, both for execution of particular functions and for access to information. The policy differences
between these domains have to be bridged automatically or through policy agreements, defining sets of
rules followed by the parties involved, for achieving interoperability.
Another challenge to be met is how to improve the quality of care by using IT without infringing the
privacy of the patient. To provide physicians with adequate information about the patient, a virtual
electronic health care record is required which makes it possible to keep track of all the activities
belonging to one patient regardless of where and by whom they have been performed and documented.
In such an environment, a generic model or specific agreement between the parties for managing
privileges and access control including the patient or its representative is needed.
Besides a diversity of roles and responsibilities, typical for any type of large organization, also ethical
and legal aspects in the healthcare scenario due to the sensitivity of person-related health information
managed and its personal and social impact have to be considered.
Advanced solutions for privilege management and access control are required today already, but
this challenge will even grow over the next couple of years. The reason is the increase of information
exchanged between systems in order to fulfil the demands of health service providers at different care
levels for having access to more and more patient-related information to ensure the quality and efficiency
of patient’s diagnosis and treatment, however combined with increased security and privacy risks.
The implementation of this International Standard might be currently too advanced and therefore not
feasible in certain organizational and technical settings. For meeting the basic principle of best possible
action, it is therefore very important that at least a policy agreement is written between the parties
stating to progress towards this International Standard when any update/upgrade of the systems is
intended. The level of formalization and granularity of policies and the objects these policies are bound
to defines the solution maturity on a pathway towards the presented specification.
The policy agreement also has to contain defined differences in the security systems and agreed
solutions on how to overcome the differences. For example, the authentication service and privileges
of a requesting party at the responding site have to be managed according to the policy declared in
the agreement. For that reason, information and service requester, as well as information and service
provider on the one hand, and information and services requested and provided on the other hand, have
to be grouped and classified in a limited number of concepts for enabling the specification of a limited
number of solution categories. Based on that classification, claimant mechanisms, target sensitivity
mechanisms, and policy specification and management mechanisms can be implemented. Once all
parties have signed the policy agreement, the communication and information exchange can start with
the existing systems if the parties can accept the risks. If there are unacceptable risks which have to be
eliminated before the information exchange starts, they shall also be recorded in the policy agreement
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ISO 22600-2:2014(E)

together with an action plan stating how these risks shall be removed. The policy agreement also has to
contain a time plan for this work and an agreement on how it shall be financed.
The documentation of the negotiation process is very important and provides the platform for the policy
agreement.
Privilege management and access control address security and privacy services required for
communication and cooperation, i.e. distributed use of health information. It also implies safety aspects,
professional standards, and legal and ethical issues. This International Standard introduces principles
and specifies services needed for managing privileges and access control. Cryptographic protocols are
out of the scope of this International Standard.
This three-part International Standard references existing architectural and security standards as well
as specifications in the healthcare area such as ISO, CEN, ASTM, OMG, W3C, etc., and endorses existing
appropriate standards or identifies enhancements or modifications or the need for new standards. It
comprises of:
— ISO 22600-1: describes the scenarios and the critical parameters in information exchange across
policy domains. It also gives examples of necessary documentation methods as the basis for the
policy agreement.
— ISO 22600-2: describes and explains, in a more detailed manner, the architectures and underlying
models for privilege management and access control which are necessary for secure information
sharing including the formal representation of policies.
— ISO 22600-3: describes examples of implementable specifications of application security services
and infrastructural services using different specification languages.
It accommodates policy bridging. It is based on a conceptual model where local authorization servers and
cross border directory and policy repository services can assist access control in various applications
(software components). The policy repository provides information on rules for access to various
application functions based on roles and other attributes. The directory service enables identification
of the individual user. The granted access will be based on four aspects:
— the authenticated identification of principals (i.e. human users and objects that need to operate
under their own rights) involved;
— the rules for access to a specific information object including purpose of use;
— the rules regarding authorization attributes linked to the principal provided by the authorization
manager;
— the functions of the specific application
This International Standard supports collaboration between several authorization managers that can
operate over organizational and policy borders.
This International Standard is strongly related to other ISO/TC 215 work such as ISO 17090 (all parts),
ISO 22857, ISO 21091, and ISO 21298.
This International Standard is meant to be read in conjunction with its complete set of associated
standards.
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INTERNATIONAL STANDARD ISO 22600-2:2014(E)
Health informatics — Privilege management and access
control —
Part 2:
Formal models
1 Scope
This multi-part International Standard defines principles and specifies services needed for managing
privileges and access control to data and/or functions.
It focuses on communication and use of health information distributed across policy domain boundaries.
This includes healthcare information sharing across unaffiliated providers of healthcare, healthcare
organizations, health insurance companies, their patients, staff members, and trading partners by
both individuals and application systems ranging from a local situation to a regional or even national
situation.
It specifies the necessary component-based concepts and is intended to support their technical
implementation. It will not specify the use of these concepts in particular clinical process pathways.
This part of ISO 22600 introduces the underlying paradigm of formal high-level models for architectural
components. It is based on ISO/IEC 10746 (all parts) and introduces the domain model, the document
model, the policy model, the role model, the authorization model, the delegation model, the control
model, and the access control model.
The specifications are provided using the meta-languages Unified Modelling Language (UML) and
Extensible Markup Language (XML). Additional diagrams are used for explaining the principles. The
attributes used have been referenced to the HL7 reference information model (see ISO 21731:2006) and
the HL7 data type definitions.
The role model has been roughly introduced referring to ISO 21298.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
1)
ISO 21298:— , Health informatics — Functional and structural roles
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
access control
means of ensuring that the resources of a data processing system can be accessed only by authorized
entities in authorized ways
[SOURCE: ISO/IEC 2382-8:1998]
1) To be published.
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3.2
accountability
property that ensures that the actions of an entity can be traced uniquely to the entity
[SOURCE: ISO 7498-2:1989]
3.3
attribute authority
AA
authority which assigns privileges by issuing attribute certificates
[SOURCE: ISO/IEC 9594-8:2008]
3.4
attribute certificate
data structure, digitally signed by an attribute authority, that binds some attribute values with
identification about its holder
[SOURCE: ISO/IEC 9594-8:2008]
3.5
authentication
provision of assurance of the claimed identity of an entity by securely associating an identifier and its
authenticator
Note 1 to entry: See also data origin authentication and peer entity authentication.
[SOURCE: ISO/IEC 15944-5:2008, 3.5]
3.6
authority
entity, which is responsible for the issuance of certificates
Note 1 to entry: Two types are distinguished in this part of ISO 22600: certification authority which issues public
key certificates and attribute authority which issues attribute certificates.
3.7
authorization
granting of privileges, which includes the granting of privileges to access data and functions
[SOURCE: ISO 7498-2:1989, modified]
3.8
availability
property of being accessible and useable upon demand by an authorized entity
[SOURCE: ISO 7498-2:1989]
3.9
certificate validation
process of ensuring that a certificate was valid at a given time, including possibly the construction and
processing of a certification path, and ensuring that all certificates in that path were valid (i.e. were not
expired or revoked) at that given time
3.10
certification authority
CA
certificate issuer; an authority trusted by one or more relying parties to create, assign, and manage
certificates
Note 1 to entry: Optionally, the certification authority can create the relying parties’ keys. The CA issues
certificates by signing certificate data with its private signing key.
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Note 2 to entry: Authority in the CA term does not imply any government authorization, only that it is trusted.
Certificate issuer can be a better term but CA is used very broadly.
[SOURCE: ISO/IEC 9594-8:2008]
3.11
certification path
ordered sequence of certificates of objects in the DIT which, together with the public key of the initial
object in the path, can be processed to obtain that of the final object in the path
3.12
confidentiality
property that information is not made available or disclosed to unauthorized individuals, entities, or
processes
[SOURCE: ISO 7498-2:1989]
3.13
credential
prerequisite issued evidence for the entitlement of, or the eligibility for, a role
3.14
delegation
conveyance of privilege from one entity that holds such privilege to another entity
3.15
delegation path
ordered sequence of certificates which, together with authentication of a privilege asserter’s identity,
can be processed to verify the authenticity of a privilege asserter’s privilege
3.16
environmental variables
aspects of policy required for an authorization decision that are not contained within static structures,
but are available through some local means to a privilege verifier (e.g. time of day or current account
balance)
3.17
identification
performance of tests to enable a data processing system to recognize entities
[SOURCE: ISO/IEC 2382-8:1998]
3.18
identifier
piece of information used to claim an identity, before a potential corroboration by a corresponding
authenticator
[SOURCE: ENV 13608-1:2000]
3.19
integrity
property that information is not altered in any way, deliberately or accidentally
3.20
key
sequence of symbols that controls the operations of encipherment and decipherment
[SOURCE: ISO 7498-2:1989]
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3.21
non-repudiation
service providing proof of the integrity and origin of data (both in an unforgeable relationship) which
can be verified by any party
[SOURCE: ISO 17090-1:2013]
3.22
policy
set of legal, political, organizational, functional, and technical obligations for communication and
cooperation
3.23
policy agreement
written agreement where all involved parties commit themselves to a specified set of policies
3.24
principal
human users and objects that need to operate under their own rights
[SOURCE: OMG Security Services Specification: 2001]
3.25
private key
key that is used with an asymmetric cryptographic algorithm and whose possession is restricted
(usually to only one entity)
[SOURCE: ISO/IEC 10181-1:1996]
3.26
privilege
capacity assigned to an entity by an authority according to the entity’s attribute
3.27
privilege asserter
privilege holder using their attribute certificate or public key certificate to assert privilege
3.28
privilege management infrastructure
PMI
infrastructure able to support the management of privileges in support of a comprehensive authorization
service and in relationship with a public key infrastructure
3.29
privilege policy
policy that outlines conditions for privilege verifiers to provide/perform sensitive services to/for
qualified privilege asserters
Note 1 to entry: Privilege policy relates attributes associated with the service as well as attributes associated
with privilege asserters.
3.30
privilege verifier
entity verifying certificates against a privilege policy
3.31
public key
key that is used with an asymmetric cryptographic algorithm and that can be made publicly available
[SOURCE: ISO/IEC 10181-1:1996]
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3.32
public key certificate
PKC
certificate that binds an identity and a public key
[SOURCE: ISO/IEC 9594-8:2008]
Note 1 to entry: The identity can be used to support identity-based access control decisions after the client proves
that it has access to the private key that corresponds to the public key contained in the PKC (see RFC 2459).
3.33
role
set of competences and/or performances that are associated with a task
3.34
role assignment certificate
certificate that contains the role attribute, assigning one or more roles to the certificate holder
3.35
role certificate
certificate that assigns privileges to a role rather than directly to individuals
Note 1 to entry: Individuals assigned to that role, through an attribute certificate or public key certificate with
a subject directory attributes extension containing that assignment, are indirectly assigned the privileges
contained in the role certificate.
3.36
role specification certificate
certificate that contains the assignment of privileges to a role
3.37
sensitivity
characteristic of a resource that implies its value or importance
3.38
security
combination of availability, confidentiality, integrity, and accountability
[SOURCE: ENV 13608-1:2000]
3.39
security policy
plan or course of action adopted for providing computer security
[SOURCE: ISO/IEC 2382-8:1998]
Note 1 to entry: The set of rules laid down by the security authority governing the use and provision of security
services and facilities constitutes its security policy.
3.40
security service
service, provided by a layer of communicating open systems, which ensures adequate security of the
systems or of data transfers
[SOURCE: ISO 7498-2:1989]
3.41
source of authority
SOA
attribute authority that a privilege verifier for a particular resource trusts as the ultimate authority to
assign a set of privileges
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3.42
target
resource being accessed by a claimant
Note 1 to entry: Its sensitivity is modelled in this part of ISO 22600 as a collection of attributes, represented as
either ASN.1 attributes or XML elements.
3.43
trust
circumstance existing between two entities whereby one entity makes the assumption that the other
entity will behave exactly as the first entity expects
Note 1 to entry: This trust applies only for some specific function. The key role of trust in this framework is to
describe the relationship between an authenticating entity and an authority; an entity must be certain that it can
trust the authority to create only valid and reliable certificates.
4 Abbreviated terms
AA Attribute Authority
PKC Public Key Certificate
UML Unified Modelling Language
XML Extensible Markup Language
5 Component paradigm
The framework for a future-proof health information system architecture is based on the generic
component model developed in the mid-nineties (e.g. References [1], [2], and [3]). Bases of that architecture
are a reference information model (RIM) and agreed vocabularies enabling interoperability. Referenced
to them, domain-specific constraint models will be specified which represent domain-specific knowledge
concepts, considering both structural and functional knowledge. The corresponding components have
to be established according to all views of the ISO/IEC 10746-1 reference model of open distributed
processing (RM-ODP), i.e. enterprise view, information view, computational view, engineering view, and
technology view. A view focuses consideration on one aspect abstracting from all others. The different
domain concepts and their view representation is not the task of programmers but of domain experts.
For that reason, they will use appropriate expression means such as specific graphical representation
(e.g. UML diagrams) or structured text expressed in XML.
The components can be aggregated to a higher level of composition. Contrary to the ISO
definition of primitives and composition, in the generic component model at least four levels of
composition/decomposition have been defined (Figure 1).
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Figure 1 — Generic component model
The aggregation is performed according to content- or process-related knowledge expressed by
logics/algorithms/operations or rules/workflows/procedures/relationships. So, the aggregation of
the building blocks “constraint models” is controlled by the aforementioned mechanisms or by the
communicating or co-operating principal’s behaviour. The specification is completely provided at meta-
level. Different vocabularies as well as tooling environment and functionality are harmonized by meta-
[4]
languages like XML Metadata Interchange (XMI).
6 Generic models
6.1 Framework
Privilege management and authorization can be based on roles that individual actors or groups of
individual actors play. Actors interacting with system components are called principals, which can be a
human user, a system, a device, an application, a component, or even an object.
In order to obtain the above-described structure and functionality, there are a number of models,
mechanisms, processes, objects, etc. needed, which have to be considered.
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Regarding privilege management and access control management, two basic class types shall be dealt
with:
— entities:
— documents;
— principals;
— policies;
— roles;
— acts:
— policy management;
— principal management;
— privilege management;
— authentication;
— authorization;
— access control management;
— audit.
The following models will be considered in more detail:
— domain model;
— document model;
— policy model;
— role model;
— authorization model;
— control model;
— delegation model;
— access control model.
All specifications in this framework will be kept open, platform-independent, portable, and scalable.
Therefore, the models provided are described at meta-model level and at the model level keeping the
instance level out of consideration. For expressing systems in such a way, specific languages and meta-
languages are used su
...