A better understanding Safety versus Security
Jan 19, 2015
A better understanding
Safety versus Security
The author
Stéphane POTIER Technology Marketing Manager
B&R Automation
Perfection in Automation www.br-automation.com
Safety
Safety is freedom from unacceptable risk of physical injury or of
damage to the health of people, either directly, or indirectly as a
result of damage to property or to the environment.
Safety is an attribute of Dependability.
Definition
Dependability
Dependability of a system is the ability to deliver service that can
justifiably be trusted.
Dependability is a measure of a system's availability, reliability,
safety, integrity and its maintainabilty
Definition
Security
Security is the prevention of illegal or unwanted penetration,
intentional or unintentional interference with the proper and intended
operation, or inappropriate access to confidential information in
industrial automation and control systems.
Security is a composite of availability, confidentiality and integrity.
Definition
Dependability & Security attributes
• Availability - readiness for correct service (usually expressed as a
percentage of uptime in a given year)
• Reliability - continuity of correct service (typically expressed as a
probability of failure-free system operation over a specified time)
• Safety - absence of catastrophic consequences or severe injuries
on the users and the environment
• Confidentiality: absence of unauthorized disclosure of information
• Integrity - absence of improper system alteration
• Maintainability - ability for a process to undergo modifications and
repairs
Definition
Dependability attributes
Relationship
Dependability
Availability
Reliability
Safety
Confidentiality
Integrity
Maintainability
Security attributes
Relationship
Security
Availability
Reliability
Safety
Confidentiality
Integrity
Maintainability
Functional Safety
Functional safety is part of the overall safety that depends on a
system or equipment operating correctly in response to its inputs.
including the safe management of likely operator errors, hardware
failures and environmental changes.
IEC 61508 is intended to be a basic functional safety standard
applicable to all kinds of industry.
Definition
Translation
• Dependability = Sûreté de fonctionnement
• Reliability = Fiabilité
• Availability = Disponibilité
• Maintainability = Maintenabilité
• Safety = Sécurité/Sûreté (1)
• Security = Sécurité (1)
• Integrity = Intégrité
(1) The French word « Sécurité » is used to translate
both « Safety » and « Security ». In some industries, the
word « Sûreté » is used to translate « Safety ».
French
Translation
• Dependability = Verlässlichkeit
• Reliability = Zuverlässigkeit
• Availability = Verfügbarkeit
• Maintainability = Instandhaltbarkeit
• Safety = Sicherheit (2)
• Security= Sicherheit (2)
• Integrity = Integrität
(2) The German word « Sicherheit » is used to translate
both « Safety » and « Security ». For this reason the
English terms are usually preferred.
German
References
[1] http://en.wikipedia.org/wiki/Dependability
[2] http://www.iec.ch/functionalsafety
[3] IEC/TS 62443-1-1 Industrial communication networks – Network
and system security – Part 1-1: Terminology, concepts and models
[4] A. Avizienis, J.-C. Laprie and B. Randell: Fundamental Concepts
of Dependability. Research Report No 1145, LAAS-CNRS, April
2001
[5] http://www.open-safety.org
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