Description of BS EN IEC 62645:2020 2020

1.1 General

This document establishes requirements and provides guidance for the development and management of effective computer security programmes for I&C programmable digital systems. Inherent to these requirements and guidance is the criterion that the power plant I&C programmable digital system security programme complies with the applicable country’s requirements.

This document defines adequate measures for the prevention of, detection of and reaction to malicious acts by digital means (cyberattacks) on I&C programmable digital systems. This includes any unsafe situation, equipment damage or plant performance degradation that could result from such an act, such as:

• malicious modifications affecting system integrity;

• malicious interference with information, data or resources that could compromise the delivery of or performance of the required I&C programmable digital functions;

• malicious interference with information, data or resources that could compromise operator displays or lead to loss of management of I&C programmable digital systems;

• malicious changes to hardware, firmware or software at the programmable logic controller (PLC) level.

Human errors leading to violation of the security policy and/or easing the aforementioned malicious acts are also in the scope of this document.

This document describes a graded approach scheme for assets subject to digital compromise, based on their relevance to the overall plant safety, availability, and equipment protection.

Excluded from the scope of this document are considerations related to:

• non-malevolent actions and events such as accidental failures, human errors (except those impacting the performance of cybersecurity controls) and natural events. In particular, good practices for managing applications and data, including back-up and restoration related to accidental failure, are out of scope;

  NOTE 1 Although such aspects are often covered by security programme in other normative contexts (e.g., in the ISO/IEC 27000 series or in the IEC 62443 series), this document is only focused on the protection against malicious acts by digital means (cyberattacks) on I&C programmable digital systems. The main reason is that in the nuclear generation domain, other standards and practices already cover accidental failures, unintentional human errors, natural events, etc. The focus of IEC 62645 is made to provide the maximum consistency and the minimum overlap with these other nuclear standards and practices.

• site physical security, room access control and site security surveillance systems. These systems, while not specifically addressed in this document, are to be covered by plant operating procedures and programmes;

  NOTE 2 This exclusion does not deny that cybersecurity has clear dependencies on the security of the physical environment (e.g., physical protection, power delivery systems, heating/ventilation/air-conditioning systems (HVAC), etc.).

• the aspect of confidentiality of information about I&C digital programmable systems is out of the scope of this document (see 5.4.3.2.3).

Annex A provides a rationale for and comments about the scope, definition and the document's application, and in particular about the exclusions and limitations previously mentioned.

Standards such as ISO/IEC 27001 and ISO/IEC 27002 are not directly applicable to the cyber protection of nuclear I&C programmable digital systems. This is mainly due to the specificities of these systems, including the regulatory and safety requirements inherent to nuclear facilities. However, this document builds upon the valid high level principles and main concepts of ISO/IEC 27001:2013, adapts them and completes them to fit the nuclear context.

This document follows the general principles given in the IAEA reference manual NSS17.

About BSI

BSI Group, also known as the British Standards Institution is the national standards body of the United Kingdom. BSI produces technical standards on a wide range of products and services and also supplies certification and standards-related services to businesses.