SIST EN ISO/IEC 27555:2025
(Main)Information security, cybersecurity and privacy protection - Guidelines on personally identifiable information deletion (ISO/IEC 27555:2021)
Information security, cybersecurity and privacy protection - Guidelines on personally identifiable information deletion (ISO/IEC 27555:2021)
This document contains guidelines for developing and establishing policies and procedures for deletion of personally identifiable information (PII) in organizations by specifying:
— a harmonized terminology for PII deletion;
— an approach for defining deletion rules in an efficient way;
— a description of required documentation;
— a broad definition of roles, responsibilities and processes.
This document is intended to be used by organizations where PII is stored or processed.
This document does not address:
— specific legal provision, as given by national law or specified in contracts;
— specific deletion rules for particular clusters of PII that are defined by PII controllers for processing PII;
— deletion mechanisms;
— reliability, security and suitability of deletion mechanisms;
— specific techniques for de-identification of data.
Informationssicherheit, Cybersicherheit und Datenschutz - Richtlinien zur Löschung persönlich identifizierbarer Informationen (ISO/IEC 27555:2021)
Sécurité de l’information, cybersécurité et protection de la vie privée - Lignes directrices relatives à la suppression des données à caractère personnel (ISO/IEC 27555:2021)
Le présent document contient des lignes directrices pour l’élaboration et l’établissement de politiques et de procédures de suppression des données à caractère personnel (DCP) dans les organisations en spécifiant :
— une terminologie harmonisée en matière de suppression de DCP ;
— une approche efficace en termes de définition des règles de suppression ;
— une description des documents exigés ;
— une définition au sens large des rôles, des responsabilités et des processus.
Le présent document s’adresse aux organisations dans lesquelles sont stockées ou traitées des DCP.
Le présent document ne traite pas :
— les dispositions légales particulières, énoncées par une législation nationale ou spécifiées dans des contrats ;
— les règles de suppression spécifiques concernant des clusters particuliers de DCP, définies par les responsables de traitement de DCP pour traiter les DCP ;
— les mécanismes de suppression ;
— la fiabilité, la sécurité et l’adéquation des mécanismes de suppression ;
— les techniques spécifiques de désidentification des données.
Informacijska varnost, kibernetska varnost in varstvo zasebnosti - Smernice o izbrisu identifikacijskih podatkov (ISO/IEC 27555:2021)
Ta dokument vsebuje smernice za oblikovanje in vzpostavitev pravilnikov in postopkov za izbris identifikacijskih podatkov (PII) v organizacijah z določitvijo: – usklajene terminologije za izbris identifikacijskih podatkov; – pristopa za učinkovito opredelitev pravil za izbris; – opisa zahtevane dokumentacije; – široke opredelitve vlog, odgovornosti in procesov. Ta dokument naj bi uporabljale organizacije, v katerih se identifikacijski podatki shranjujejo oziroma obdelujejo. Ta dokument ne obravnava: – posebne pravne določbe, kot jo določa nacionalna zakonodaja ali je navedena v pogodbah; – posebnih pravil za izbris posameznih skupin identifikacijskih podatkov, ki jih upravljavci identifikacijskih podatkov opredelijo za njihovo obdelavo; – mehanizmov za izbris; – zanesljivosti, varnosti in primernosti mehanizmov za izbris; – posebnih tehnik za deidentifikacijo podatkov.
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-maj-2025
Informacijska varnost, kibernetska varnost in varstvo zasebnosti - Smernice o
izbrisu identifikacijskih podatkov (ISO/IEC 27555:2021)
Information security, cybersecurity and privacy protection - Guidelines on personally
identifiable information deletion (ISO/IEC 27555:2021)
Informationssicherheit, Cybersicherheit und Datenschutz - Richtlinien zur Löschung
persönlich identifizierbarer Informationen (ISO/IEC 27555:2021)
Sécurité de l’information, cybersécurité et protection de la vie privée - Lignes directrices
relatives à la suppression des données à caractère personnel (ISO/IEC 27555:2021)
Ta slovenski standard je istoveten z: EN ISO/IEC 27555:2025
ICS:
35.030 Informacijska varnost IT Security
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD EN ISO/IEC 27555
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2025
ICS 35.030
English version
Information security, cybersecurity and privacy protection
- Guidelines on personally identifiable information
deletion (ISO/IEC 27555:2021)
Sécurité de l'information, cybersécurité et protection Informationssicherheit, Cybersicherheit und
de la vie privée - Lignes directrices relatives à la Datenschutz - Richtlinien zur Löschung persönlich
suppression des données à caractère personnel identifizierbarer Informationen (ISO/IEC 27555:2021)
(ISO/IEC 27555:2021)
This European Standard was approved by CEN on 7 March 2025.
CEN and CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for
giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical
references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to
any CEN and CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN and CENELEC member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.
CEN and CENELEC members are the national standards bodies and national electrotechnical committees of Austria, Belgium,
Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia,
Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and United Kingdom.
CEN-CENELEC Management Centre:
Rue de la Science 23, B-1040 Brussels
© 2025 CEN/CENELEC All rights of exploitation in any form and by any means
Ref. No. EN ISO/IEC 27555:2025 E
reserved worldwide for CEN national Members and for
CENELEC Members.
Contents Page
European foreword . 3
European foreword
The text of ISO/IEC 27555:2021 has been prepared by Technical Committee ISO/IEC JTC 1 "Information
technology” of the International Organization for Standardization (ISO) and has been taken over as
Protection” the secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by September 2025, and conflicting national standards
shall be withdrawn at the latest by September 2025.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN-CENELEC shall not be held responsible for identifying any or all such patent rights.
This document has been prepared under a standardization request addressed to CEN and CENELEC by
the European Commission. The Standing Committee of the EFTA States subsequently approves these
requests for its Member States.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN and CENELEC websites.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO/IEC 27555:2021 has been approved by CEN-CENELEC as EN ISO/IEC 27555:2025
without any modification.
INTERNATIONAL ISO/IEC
STANDARD 27555
First edition
2021-10
Information security, cybersecurity
and privacy protection — Guidelines
on personally identifiable information
deletion
Sécurité de l’information, cybersécurité et protection de la
vie privée — Lignes directrices relatives à la suppression des
informations personnellement identifiables
Reference number
ISO/IEC 27555:2021(E)
© ISO/IEC 2021
ISO/IEC 27555:2021(E)
© ISO/IEC 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
© ISO/IEC 2021 – All rights reserved
ISO/IEC 27555:2021(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms.3
5 Framework for deletion . 3
5.1 General . 3
5.2 Constraints. 4
5.3 Clusters of PII . 4
5.4 Retention period and regular deletion period . 5
5.4.1 Retention period . 5
5.4.2 Regular deletion period . 5
5.4.3 Allocation of clusters of PII . 6
5.5 Archives and backup copies . . 6
5.6 Standard deletion periods, starting points, deletion rules and deletion classes . 7
5.7 Special situations . 7
5.8 Documentation of policies and procedures . 8
6 Clusters of PII . 8
6.1 General . 8
6.2 Identification . 9
6.3 Documentation . 10
7 Specification of deletion periods .10
7.1 Standard and regular deletion periods . 10
7.2 Regular deletion period specifications . 11
7.3 Standard deletion period identification . 11
7.4 Deletion period specifications for special situations .12
7.4.1 General .12
7.4.2 Modification of data objects .12
7.4.3 Need to extend period of active use . 13
7.4.4 Suspension of the deletion . 13
7.4.5 Backup copies . 13
8 Deletion classes .14
8.1 Abstract starting points — abstract deletion rules . 14
8.2 Matrix of deletion classes.15
8.3 Allocation of deletion classes and definition of deletion rules . 16
9 Requirements for implementation .16
9.1 General . 16
9.2 Conditions for starting points outside IT systems . 18
9.3 Requirements for implementation for organization-wide aspects . 18
9.3.1 General . 18
9.3.2 Backup . 18
9.3.3 Logs . 19
9.3.4 Transmission systems . 19
9.3.5 Repair, dismantling and disposal of systems and components . 19
9.3.6 Everyday business life . 19
9.4 Requirements for implementation for individual IT systems . 20
9.5 Deletion in regular manual processes . 21
9.6 Requirements for implementation for PII processor . 21
9.7 Control deletion in special cases . 21
9.7.1 Exception management . 21
iii
© ISO/IEC 2021 – All rights reserved
ISO/IEC 27555:2021(E)
9.7.2 Further sets of PII . 22
10 Responsibilities . .22
10.1 General .22
10.2 Documentation .23
10.3 Implementation . . 24
Bibliography .25
iv
© ISO/IEC 2021 – All rights reserved
ISO/IEC 27555:2021(E)
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.
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.
v
© ISO/IEC 2021 – All rights reserved
ISO/IEC 27555:2021(E)
Introduction
Many functional processes and IT applications use personally identifiable information (PII), which is
subject to various compliance provisions relating to privacy. Thus, organizations need to ensure that
PII is not retained for longer than is necessary and that it is deleted at the appropriate time. This can
require organizations to fulfil the rights of PII principals, such as the right to obtain erasure (to be
forgotten). ISO/IEC 29100 defines principles of “data minimization” and “use, retention and disclosure
limitation” for PII, which can be enforced using deletion as a security control.
PII deletion requires a set of carefully designed, clear and easily understood deletion rules, embodying
appropriate retention periods that satisfy the demands of multiple stakeholders. These rules should
also conform with requirements originating from codes of practice and other standards. Mechanisms
are to be correctly implemented and appropriately operated. In order to ensure the legally compliant
deletion of PII, the PII controller needs to develop policies and procedures for deletion that include a set
of rules and responsibilities for the processes involved. The chances of success for the development and
implementation of these policies and processes can be improved if the PII controller uses a recognized
approach to their design and implementation.
This document provides a framework for developing and establishing policies and procedures for PII
deletion that can be implemented by an organization. This framework allows for consistent deletion of
PII throughout an organization.
vi
© ISO/IEC 2021 – All rights reserved
INTERNATIONAL STANDARD ISO/IEC 27555:2021(E)
Information security, cybersecurity and privacy
protection — Guidelines on personally identifiable
information deletion
1 Scope
This document contains guidelines for developing and establishing policies and procedures for deletion
of personally identifiable information (PII) in organizations by specifying:
— a harmonized terminology for PII deletion;
— an approach for defining deletion rules in an efficient way;
— a description of required documentation;
— a broad definition of roles, responsibilities and processes.
This document is intended to be used by organizations where PII is stored or processed.
This document does not address:
— specific legal provision, as given by national law or specified in contracts;
— specific deletion rules for particular clusters of PII that are defined by PII controllers for processing
PII;
— deletion mechanisms;
— reliability, security and suitability of deletion mechanisms;
— specific techniques for de-identification of data.
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 29100:2011, Information technology — Security techniques — Privacy framework
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC 29100 and the following
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/
© ISO/IEC 2021 – All rights reserved
ISO/IEC 27555:2021(E)
3.1
cluster of personally identifiable information
cluster of PII
personally identifiable information which is processed for a consistent functional purpose
Note 1 to entry: Clusters of PII are described independently of the technical representation of data objects. On a
regular basis, the clusters of PII also include PII which is not stored electronically.
3.2
data object
element which contains personally identifiable information (PII)
EXAMPLE Examples of elements include files, documents, records or attributes. Concrete data objects
include, for example, invoices, contracts, personal files, visitor lists, personnel planning sheets, photos, voice
recordings, user accounts, log entries and consent documents.
Note 1 to entry: In the context of this document, data objects usually contain PII and can be combined with other
data objects in a cluster of PII (3.1). The individual data object can be of varying complexity.
3.3
deletion
process by which personally identifiable information (PII) is changed so that it is no longer present or
recognizable and usable and can only be reconstructed with excessive effort
Note 1 to entry: In this document the term deletion has the following synonyms: disposition mechanism, erasure,
destruction, destruction of data storage media.
Note 2 to entry: In this document the term deletion refers to the elimination of the bit patterns or comparable
practices, not simply marking or moving the data to be hidden. As a result, excessive effort for PII reconstruction
is required, considering all the means likely to be used, e.g. available state-of-the-art technology, human and
technical resources, costs and time.
Note 3 to entry: For selecting the methods for deletion, a risk-based approach should be taken into account,
including sensitivity of PII and potential use of forensic tools. Required measures can change over time depending
on the state of the art of technology and other factors.
Note 4 to entry: PII can be also changed by applying an irreversible de-identification technique. Such data often
fall out of the scope of privacy legislation. Further guidance on a de-identification technique can be found in ISO/
IEC 20889:2018, Clause 11.
3.4
deletion class
combination of a standard deletion period (3.7) and an abstract starting point for the period run
Note 1 to entry: All clusters of personally identifiable information (PII) which are subject to the same deletion
period (3.6) and the same abstract starting point are combined in a deletion class. As opposed to the (specific)
deletion rule (3.5) for a cluster of PII (3.1), the (abstract) deletion class relates only to the abstract starting point
and not to a specific condition for the start of the period run (see also Clause 8).
3.5
deletion rule
combination of deletion period (3.6) and specific condition for the starting point of the period run
3.6
deletion period
time period after which a specific cluster of personally identifiable information (PII) (3.1) should be
deleted
Note 1 to entry: As a generic term, the deletion period comprises all deletion periods. This includes the standard
deletion periods (3.7) and the regular deletion periods (3.8), which form special groups. However, the term also
includes, for instance, the specific deletion periods for some clusters of PII or deletion periods in special cases.
For details, see Clause 7.
© ISO/IEC 2021 – All rights reserved
ISO/IEC 27555:2021(E)
Note 2 to entry: The deletion period for a cluster of PII extends beyond the end of the retention period (3.9), by at
least an amount commensurate with the time required to achieve deletion of the relevant data objects (3.2).
3.7
standard deletion period
unified deletion period for the personally identifiable information (PII) controller
Note 1 to entry: A standard deletion period is a deletion period (3.6) used for several clusters of PII (3.1) to
standardize several deletion periods lying close to one another (see 7.1).
3.8
regular deletion period
maximum time period after which the data objects (3.2) of a cluster of personally identifiable information
(PII) (3.1) should be deleted if used in regular processing in the processes of the PII controller
Note 1 to entry: For the boundary conditions of period specifications, see 5.4.
3.9
retention period
time period within which the data objects (3.2) of the cluster of personally identifiable information (PII)
(3.1) are required to be available in the PII controller’s organization because of functional use or legal
retention obligations
Note 1 to entry: A specific cluster of PII typically has the same retention period.
Note 2 to entry: For the boundary conditions of period specifications, see 5.4 and Clause 7.
3.10
legal retention period
time period within which the data objects (3.2) of a cluster of personally identifiable information (PII)
(3.1) are available in the PII controller’s organization as required by legal provisions
4 Symbols and abbreviated terms
CD compact disc
DVD digital versatile disc
IT information technology
PII personally identifiable information
PDF portable document format
SD secure digital
USB universal serial bus
5 Framework for deletion
5.1 General
This document describes how an organization acting as PII controller can establish policies and
procedures for deletion of PII. For this, the PII controller should specify:
— which deletion rules apply to which PII;
— how the deletion is implemented using the deletion rules;
— how the deletion rules and the deletion measures are documented;
© ISO/IEC 2021 – All rights reserved
ISO/IEC 27555:2021(E)
— who is responsible for the deletion rules, deletion processes and their documentation.
To establish deletion policies and procedures, the following steps are recommended:
— select a minimum number of standard deletion periods which form the basis of deletion classes;
— base deletion classes on the standard deletion periods identified;
— allocate each cluster of PII to a deletion class;
— identify and document the deletion procedure.
The PII controller should implement deletion mechanisms for each cluster of PII based on the established
policies and procedures (see 10.3).
5.2 Constraints
The PII controller should establish policies and procedures for deletion of PII which enable the
organization to demonstrate compliance with relevant legal, regulatory and other requirements.
Where the organization is performing the role of a PII processor, they should ensure deletion rules are
implemented in accordance with the relevant PII controller instructions.
Where compliance and/or contractual requirements state that PII should be deleted when it is no longer
required for the defined purpose, the principles contained in ISO/IEC 29100 should be considered when
designing the deletion processes:
a) use, retention and disclosure limitation;
b) data minimization.
EXAMPLE The deletion rule for the cluster of PII named “Accounting data” can be 10 years after the end of
the financial year in which the accounting entry was made in the balance sheet.
Compliance and/or contractual requirements can require special measures, particularly where clusters
of PII are retained only to fulfil retention obligations. In such cases, restricting the processing of the
clusters of PII concerned can be required.
5.3 Clusters of PII
Clusters of PII should be named individually and unambiguously and according to their functional
purposes. Each cluster of PII should be allocated one deletion rule (see 6.2).
EXAMPLE For a telecommunications provider, customer data, location data, traffic data, billing data and
itemized bill data are possible names of clusters of PII.
The same PII can be part of more than one cluster of PII because of two cases:
— clusters of PII contain one or more data objects;
NOTE Some attributes, such as name or address, can occur in several data objects in the same or different
clusters of PII, e.g. in the customer master data, an invoice and a letter to the customer. Deletion is usually applied
on the data object as a whole (and not on single attributes within the data object).
— copies of a data object can be part of different clusters of PII.
EXAMPLE Assume an invoice documents materials and actions performed to repair an engine. Functional
processes can require that three copies of the document are stored in different clusters of PII: “bookkeeping data”
(deleted 11 years after payment), “engine documentation file” to document the history and parts of the engine
(deleted 5 years after destruction of the engine) and “supplier file” to document the history of the relationship
and operations with the supplier (deleted 15 years after receiving the data object).
PII should not be deleted upon individual case decisions only, but in accordance with appropriate
deletion rules wherever possible. Therefore, the PII controller should develop deletion rules in
© ISO/IEC 2021 – All rights reserved
ISO/IEC 27555:2021(E)
accordance with their deletion policy. Every deletion rule should include a definition of the deletion
period and when the deletion period begins (starting point).
5.4 Retention period and regular deletion period
5.4.1 Retention period
The period of time for which a cluster of PII is retained, based on its functional purposes (which
can include retention period complying with business requirements as well as legal and statutory
obligations), is its retention period. This time period includes the time period in which a cluster of PII is
actively used in functional processes, in accordance with compliance and/or contractual purposes and
in accordance with the organization's long-term storage requirements.
EXAMPLE The legal retention obligations for clusters of PII include, for example, the provisions of tax laws
for trade letters and accounting documents. Functional purposes include, for example, guarantee commitments
and potential equipment recall actions.
5.4.2 Regular deletion period
Clusters of PII should not be deleted until the end of their defined retention period, unless specific
approvals have been obtained.
Legal obligations can allow for time flexibility to perform deletion after the retention period has been
reached. This flexibility can be used to apply a process and mechanisms for deletion which may take
into account the availability of technical solutions as well as the general organizational requirements.
The combination of the retention period and the maximum time period for the deletion process is
defined as the regular deletion period. The PII controller should estimate the maximum time period
that is acceptable for the deletion process.
Each deletion rule should be applied by deleting data objects within a cluster of PII in all systems and
all storage places. This should include the deletion of data objects stored in physical documents. Also
included is the deletion of clusters of PII processed by PII processors contracted by the PII controller.
Figure 1 shows an example of how to derive a regular deletion period based on the life cycle of an order.
The retention period and regular deletion period for the order starts with the formation of the contract.
The active use of the contract ends with the receipt of payment. After that, the contract is still retained
for possible warranty cases and as a trade letter.
© ISO/IEC 2021 – All rights reserved
ISO/IEC 27555:2021(E)
Figure 1 — Example of regular deletion period for an order
NOTE In the example in Figure 1, the retention period for the order is shorter than the regular deletion
period. Depending on which cluster of PII is involved and its defined deletion period, the retention period and the
regular deletion period sometimes have nearly the same duration. The invoice and the booking of the payment
received are categorized as separate clusters of PII and, therefore, have different deletion rules.
5.4.3 Allocation of clusters of PII
The allocation of clusters of PII to specific standard deletion periods should be based on compliance
and/or contractual requirements in alignment with business needs. The number of standard deletion
periods should be as low as possible and should be the minimum required in order to meet these
requirements and business needs. For further information on standard deletion periods, see 7.1.
The PII controller should consider relevant legal, regulatory and/or contractual business requirements
giving specific deletion provisions when defining regular deletion periods. These provisions can also
include guidelines for the design of the deletion processes.
EXAMPLE In the area of telecommunications, the retention of traffic data required for calculating usage
charges is sometimes limited by law.
Further guidance for the allocation of regular deletion periods to clusters of PII can be found in Clause 7
and 8.3.
5.5 Archives and backup copies
Archives serve the purpose of keeping data available for extended periods of time. Data are transferred
into archives when they are no longer expected to be actively used but are still required to be retained
for permissible reasons. An archive can contain different clusters of PII with different deletion periods.
The relevant compliance and/or contractual requirements can require restriction of processing for
archived data.
The primary purpose of backup copies is the recovery of IT systems. Backup copies should not be used
as archives.
© ISO/IEC 2021 – All rights reserved
ISO/IEC 27555:2021(E)
The organization should clearly distinguish between backup copies and archives. PII contained in
archives should be subject to the same deletion rules of the respective clusters of PII and these rules
should be implemented in the archives concerned.
It is often impractical (or even impossible) to delete individual data objects within a backup copy, as
it would contradict the purpose of a backup. To fulfil their purpose, backup copies are required to be
available for only short periods of time. Using short deletion periods for the backup copies is a means of
conforming with the deletion provisions.
For the deletion of backup copies, individual time periods should be specified in the backup strategy
(see 9.3). These time periods should be in acceptable proportion to the regular deletion periods of the
various clusters of PII contained in the specific copy (see 7.4).
During recovery of a system, PII which has exceeded the regular deletion period can be restored.
Therefore, restore processes should consider this possibility and describe how to delete such restored
PII (see 9.1 and 9.4).
5.6 Standard deletion periods, starting points, deletion rules and deletion classes
Before deletion rules can be defined for individual clusters of PII, considerable effort can be required for
analysis. It is appropriate to involve the person responsible for privacy matters within the organization
in the assessment of the standard deletion periods, starting points, deletion rules and deletion classes.
The PII controller should define and use standard deletion periods.
The starting points for the deletion periods may also be grouped (see 8.1).
EXAMPLE One such abstract starting point is the “collection of the data”; another is the “end of procedure”.
The combination of a standard deletion period and an abstract starting point forms a deletion class (see
Clause 8). Clusters of PII should be assigned to the appropriate deletion class. For example, all clusters
of PII which are subject to the same deletion period and the same starting point should be assigned to
the same deletion class.
5.7 Special situations
In some situations, deleting PII in accordance with the general deletion rules can be unfeasible for an
organization. These situations include:
— deletion of PII which was collected without proper legal permission;
— deletion of PII after a legally founded request for deletion by the PII principal;
— deletion of PII which is likely necessary for a claim or an anticipated or ongoing legal case.
NOTE 1 In some jurisdictions, compliance requirements grant the PII principal a right to have PII deleted
if certain prerequisites are met. For a specific cluster of PII, not all such requests need to be implemented, for
example because of overriding compliance retention requirements.
For these and similar special situations, deletion measures should also be determined. These can be
specified in the context of the processes and responsibilities for deletion of PII (see 9.7 and Clause 10).
Individual PII can only be deleted if the technical systems have a suitable function for deletion.
Therefore, the PII controller should ensure that such a function is required in system procurement or
system development processes if PII principals can require the deletion on a case-by-case basis. On the
other hand, there is nothing to prevent the use of available standard functions for rare individual cases
of such deletions, e.g. SQL instructions in databases.
NOTE 2 Under certain conditions, the PII controller has the option not to delete PII but to restrict the
processing of that PII.
© ISO/IEC 2021 – All rights reserved
ISO/IEC 27555:2021(E)
5.8 Documentation of policies and procedures
Policies and procedures for PII deletion should be documented. These documents should include
advice from different entities within the organization, such as the person in charge in privacy matters,
functional users, developers and administrators.
Policies and procedures can be integrated into existing documentation. To prevent inconsistencies and
inefficiencies, duplication of policies and procedures should be avoided.
The deletion rules should be described without reference to the technology used for storage, control
and deletion.
EXAMPLE 1 Bookkeeping data include invoices, receipts and bank transactions. To be independent from
technical aspects, it is irrelevant on which media such data objects are stored (e.g. paper, hard disk, USB stick
or microfiche), in which location they are stored (e.g. locally on a laptop, in a central IT system database, using a
storage area network or paper file folders in an archive room) or which format is used (e.g. PDF, database record,
text file). The same applies to a set of videos or audio tracks: it is irrelevant whether they are stored digitally or
on “old media” such as celluloid, cassette, vinyl record or compact disk.
Technology-related requirements for implementation should be specified separately (see Clause 9 for
further information). Deletion rules should also be applied to manual processes such as data handled by
individuals, e.g. using paper-based documents or files in IT systems.
EXAMPLE 2 A job application is received on paper and stored in a file until the application process is
performed. The application is to be deleted following the appropriate deletion rule after a decision is taken
through a manual process. In other cases, PII in files is stored manually in the file system, e.g. invoices for special
verification or handling. Handling of such data can be regulated by documented work instructions, including the
need to delete the data manually.
6 Clusters of PII
6.1 General
Sets of PII should be categorized according to their functional purposes as clusters of PII. Different
purposes and, thus, different clusters of PII can result, in particular, if:
— the legal basis for the PII collection differs;
— the relevant legal requirements contain different provisions for the use of PII;
— PII relates to different PII principals;
— PII is only used for purposes pursued by different functional entities;
— PII is of different sensitivity.
The PII controller should define and document clusters of PII for the organization.
Additional clusters of PII can be identified:
— when specifying deletion classes and deletion rules for the clusters of PII already identified;
— when specifying or implementing requirements for implementation for specific sets of PII in specific
IT systems or other processes.
NOTE 1 In some cases, it is an option to subdivide individual clusters of PII.
NOTE 2 PII are structured differently (e.g. records in databases, files, paper documents) or are stored at
different locations (e.g. tables of a databas
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.
Loading comments...