ISO 17090-3:2021

INTERNATIONAL ISO
STANDARD 17090-3
Second edition
2021-03
Health informatics — Public key
infrastructure —
Part 3:
Policy management of certification
authority
Informatique de santé — Infrastructure de clé publique —
Partie 3: Gestion politique d'autorité de certification
Reference number
ISO 17090-3:2021(E)
©
ISO 2021

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ISO 17090-3:2021(E)

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ISO 17090-3:2021(E)

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviations. 1
5 Requirements for digital certificate policy management in a healthcare context.2
5.1 General . 2
5.2 Need for a high level of assurance . 2
5.3 Need for a high level of infrastructure availability . 2
5.4 Need for a high level of trust . 2
5.5 Need for Internet compatibility. 3
5.6 Need to facilitate evaluation and comparison of CPs . 3
6 Structure of healthcare CPs and healthcare CPSs . 3
6.1 General requirements for CPs . 3
6.2 General requirements for CPSs . 4
6.3 Relationship between a CP and a CPS . 4
6.4 Applicability . 4
7 Minimum requirements for a healthcare CP . 5
7.1 General requirements . 5
7.2 Publication and repository responsibilities. 5
7.2.1 Repositories . 5
7.2.2 Publication of certification information . 5
7.2.3 Frequency of publication . 5
7.2.4 Access controls on repositories . 5
7.3 Identification and authentication . 6
7.3.1 Initial registration . 6
7.3.2 Initial identity validation . 7
7.3.3 Identification and authentication for re-keying requests . 8
7.3.4 Identification and authentication for revocation request . 8
7.4 Certificate life-cycle operational requirements . 9
7.4.1 Certificate application . 9
7.4.2 Certificate application processing .10
7.4.3 Certificate issuance .10
7.4.4 Certificate acceptance .11
7.4.5 Key pair and certificate usage .11
7.4.6 Certificate renewal .12
7.4.7 Certificate re-key .13
7.4.8 Certificate modification .13
7.4.9 Certificate revocation and suspension .14
7.4.10 Certificate status services .17
7.4.11 End of subscription . .18
7.4.12 Private key escrow .18
7.5 Physical controls .18
7.5.1 General.18
7.5.2 Physical controls .18
7.5.3 Procedural controls .18
7.5.4 Personnel controls .18
7.5.5 Security audit logging procedures .18
7.5.6 Record archive .18
7.5.7 Key changeover .19
7.5.8 Compromise and disaster recovery .19
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ISO 17090-3:2021(E)

7.5.9 CA termination .19
7.6 Technical security controls .19
7.6.1 Key pair generation and installation .19
7.6.2 Private key protection .20
7.6.3 Other aspects of key management .22
7.6.4 Activation data .23
7.6.5 Computer security controls .23
7.6.6 Life-cycle technical controls .23
7.6.7 Network security controls .23
7.6.8 Time stamping .24
7.7 Certificate, CRL and OCSP profiles .24
7.8 Compliance audit .24
7.8.1 General.24
7.8.2 Frequency of CA compliance audit .24
7.8.3 Identity/qualifications of auditor .24
7.8.4 Auditor's relationship to audited party.24
7.8.5 Topics covered by audit .24
7.8.6 Actions taken as a result of deficiency .25
7.8.7 Communication of audit results .26
7.9 Other business and legal matters .26
7.9.1 Fees .26
7.9.2 Financial responsibility .26
7.9.3 Confidentiality of business information .26
7.9.4 Privacy of personal information .26
7.9.5 Intellectual property rights .27
7.9.6 Representations and warranties .27
7.9.7 Disclaimers of warranties .29
7.9.8 Limitations of liability .29
7.9.9 Indemnities .30
7.9.10 Term and termination .30
7.9.11 Individual notices and communication with participants .30
7.9.12 Amendments .30
7.9.13 Dispute resolution procedures .30
7.9.14 Governing law . .31
7.9.15 Compliance with applicable law .31
7.9.16 Miscellaneous provisions .31
8 Model PKI disclosure statement .31
8.1 Introduction .31
8.2 Structure of PKI disclosure statement .32
Bibliography .33
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ISO 17090-3:2021(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 215, Health informatics.
This second edition cancels and replaces the first edition (ISO 17090-3:2008), of which it constitutes a
minor revision. The changes compared to the previous edition are as follows:
— update to references;
— editorial update.
A list of all parts in the ISO 17090 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
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ISO 17090-3:2021(E)

Introduction
The healthcare industry is faced with the challenge of reducing costs by moving from paper-based
processes to automated electronic processes. New models of healthcare delivery are emphasizing the
need for patient information to be shared among a growing number of specialist healthcare providers
and across traditional organizational boundaries.
Healthcare information concerning individual citizens is commonly interchanged by means of
electronic mail, remote database access, electronic data interchange and other applications. The
Internet provides a highly cost-effective and accessible means of interchanging information, but it
is also an insecure vehicle that demands additional measures be taken to maintain the privacy and
confidentiality of information. Threats to the security of health information through unauthorized
access (either inadvertent or deliberate) are increasing. It is essential to have available to the healthcare
system reliable information security services that minimize the risk of unauthorized access.
How does the healthcare industry provide appropriate protection for the data conveyed across the
Internet in a practical, cost-effective way? Public key infrastructure (PKI) and digital certificate
technology seek to address this challenge.
The proper deployment of digital certificates requires a blend of technology, policy and administrative
processes that enable the exchange of sensitive data in an unsecured environment by the use of
“public key cryptography” to protect information in transit and “certificates” to confirm the identity
of a person or entity. In healthcare environments, this technology uses authentication, encipherment
and digital signatures to facilitate confidential access to, and movement of, individual health records
to meet both clinical and administrative needs. The services offered by the deployment of digital
certificates (including encipherment, information integrity and digital signatures) are able to address
many of these security issues. This is especially the case if digital certificates are used in conjunction
with an accredited information security standard. Many individual organizations around the world
have started to use digital certificates for this purpose.
Interoperability of digital certificate technology and supporting policies, procedures and practices
is of fundamental importance if information is to be exchanged between organizations and between
jurisdictions in support of healthcare applications (for example between a hospital and a community
physician working with the same patient).
Achieving interoperability between different digital certificate implementations requires the
establishment of a framework of trust, under which parties responsible for protecting an individual’s
information rights may rely on the policies and practices and, by extension, the validity of digital
certificates issued by other established authorities.
Many countries are deploying digital certificates to support secure communications within their
national boundaries. Inconsistencies will arise in policies and procedures between the certification
authorities (CAs) and the registration authorities (RAs) of different countries if standards development
activity is restricted to within national boundaries.
Digital certificate technology is still evolving in certain aspects that are not specific to healthcare.
Important standardization efforts and, in some cases, supporting legislation are ongoing. On the other
hand, healthcare providers in many countries are already using or planning to use digital certificates.
The ISO 17090 series seeks to address the need for guidance of these rapid international developments.
The ISO 17090 series describes the common technical, operational and policy requirements that need
to be addressed to enable digital certificates to be used in protecting the exchange of healthcare
information within a single domain, between domains and across jurisdictional boundaries. Its purpose
is to create a platform for global interoperability. It specifically supports digital certificate-enabled
communication across borders, but could also provide guidance for the national or regional deployment
of digital certificates in healthcare. The Internet is increasingly used as the vehicle of choice to support
the movement of healthcare data between healthcare organizations and is the only realistic choice for
cross-border communication in this sector.
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ISO 17090-3:2021(E)

The ISO 17090 series should be approached as a whole, with the five parts all making a contribution
to defining how digital certificates can be used to provide security services in the health industry,
including authentication, confidentiality, data integrity and the technical capacity to support the quality
of digital signature.
ISO 17090-1 defines the basic concepts underlying the use of digital certificates in healthcare and
provides a scheme of interoperability requirements to establish digital certificate-enabled secure
communication of health information.
ISO 17090-2 provides healthcare-specific profiles of digital certificates based on the international
[9]
standard X.509 and the profile of this, specified in IETF/RFC 5280 for different types of certificates.
This document deals with management issues involved in implementing and using digital certificates in
healthcare. It defines a structure and minimum requirements for certificate policies (CPs) and a structure
for associated certification practice statements. This document is based on the recommendations of the
informational IETF/RFC 3647, and identifies the principles needed in a healthcare security policy for
cross border communication. It also defines the minimum levels of security required, concentrating on
the aspects unique to healthcare.
ISO 17090-4 supports interchangeability of digital signatures and the prevention of incorrect or illegal
digital signatures by providing minimum requirements and formats for generating and verifying digital
signatures and related certificates.
ISO 17090-5 defines the procedural requirements for validating an entity credential based on PKI
defined in the ISO 17090 series, used in healthcare information systems including accessing remote
systems.
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INTERNATIONAL STANDARD ISO 17090-3:2021(E)
Health informatics — Public key infrastructure —
Part 3:
Policy management of certification authority
1 Scope
This document gives guidelines for certificate management issues involved in deploying digital
certificates in healthcare. It specifies a structure and minimum requirements for certificate policies, as
well as a structure for associated certification practice statements.
This document also identifies the principles needed in a healthcare security policy for cross-border
communication and defines the minimum levels of security required, concentrating on aspects unique
to healthcare.
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 17090-1:2021, Health informatics — Public key infrastructure — Part 1: Overview of digital certificate
services
ISO 17090-2:2015, Health informatics — Public key infrastructure — Part 2: Certificate profile
ISO/IEC 27002, Information technology — Security techniques — Code of practice for information security
controls
IETF/RFC 3647, Internet X.509 Public Key Infrastructure Certificate Policy and Certification Practices
Framework
IETF/RFC 4211, Internet X.509 Public Key Infrastructure Certificate Request Message Format (CRMF)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 17090-1 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 Abbreviations
AA attribute authority
CA certification authority
CP certificate policy
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ISO 17090-3:2021(E)

CPS certification practice statement
CRL certificate revocation list
OID object identifier
PKC public key certificate
PKI public key infrastructure
RA registration authority
TTP trusted third party
5 Requirements for digital certificate policy management in a healthcare context
5.1 General
Deployment of digital certificates in healthcare shall meet the following objectives in order to be
effective in securing the communication of personal health information:
— the reliable and secure binding of unique and distinguished names to individuals, organizations,
applications and devices that participate in the electronic exchange of personal health information;
— the reliable and secure binding of professional roles in healthcare to individuals, organizations and
applications that participate in the electronic exchange of personal health information, insofar as
those roles may be used as the basis of role-based access control to such health information;
— (optionally) the reliable and secure binding of attributes to individuals, organizations, applications
and devices that participate in the electronic exchange of personal health information, insofar as
those attributes may further the secure communication of
...