ISO/TS 22375:2018 セキュリティと回復力—複雑さの評価プロセスのガイドライン | ページ 2

Foreword

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This document was prepared by Technical Committee ISO/TC 292, Security and resilience.

Introduction

Complexity is a fundamental property of many systems. An appropriate level of complexity is required for systems operation, but a high degree of complexity can weaken the system, particularly during turbulent times. High system complexity could be an obstacle to the security, resilience, effectiveness and efficiency of all organizations. As organizational systems, products, processes, technologies, organizational structures and contracts become more complex, organizations may fail to pay sufficient attention to the introduction and proliferation of more complex and less secure systems that then become unsustainable and lose their integrity. Figure 1 explains where the introduction of complexity can improve performance, but where, after it reaches certain point, it will degrade performance. Point A is the best ratio between performance and complexity.

Organizational complexity cannot be increased indefinitely, however. If complexity exceeds a manageable level, e.g. interdependencies expand to the degree that all elements are connected with one another, the system behaviour turns chaotic. Hence, the relationship between organizational complexity and performance is hypothesized to be inversely u-shaped, as shown in Figure 1 ^[16].

The complexity of an organization’s system is influenced by external and internal factors, often linked to direct or indirect actions carried out by different parties.

Day-to-day managerial decisions about the organization’s activities tend to generate complexity.

For large companies with decentralized decision-making, decisions tend to be made without the assessment of complexity cost and benefit trade-offs.

These decisions could add complexity without creating customer or competitive benefits and could increase the organization’s vulnerability.

Moreover, the decisions taken by customers, competitors and suppliers, as well as the enactment of new regulations, induce the organizations to adapt themselves to new scenarios. Increasing the complexity of the external environment may induce the organization to increase the number of functional units and this could increase functional and structural complexity of the organization.

Functional complexity is characterized by its management system and its business processes set out in directives, procedures and reports.

Structural complexity deals with the variety of elements and relationships among the people, products and services, and assets of the organization.

To assess the complexity of an organization’s system, it is necessary to take into account a large number of parameters where the interactions change and develop dynamically and in a non-linear laws.

This is particularly true in the context of a turbulent and interdependent global economy, punctuated by shocks and instabilities of increasing intensity and frequency, which can undermine the performance and survival of any system.

High complexity is an important source of a new form of risk called “complexity-related risk” that organizations have to address and manage if the security and resilience of its system are to be sustained.

This document aims to stimulate organizations to take into account the threat created by an excess of complexity and to consider complexity assessment as an integral part of their plan for security management.

1 Scope

This document gives guidelines for the application of principles and a process for a complexity assessment of an organization’s systems to improve security and resilience. A complexity assessment process allows an organization to identify potential hidden vulnerabilities of its system and to provide an early indication of risk resulting from complexity.

This document is generic and applicable to all sizes and types of organization systems, such as critical assets, strategic networks, supply chains, industrial plants, community infrastructures, banks and business companies.

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.

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 22300 and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

Bibliography