[SystemSafety] Does "reliable" mean "safe" and or "secure" or neither?

Andy Ashworth andy at the-ashworths.org
Wed Apr 20 17:48:11 CEST 2016


If Integrity is interpreted as applying to a system's ability to perform in
accordance with the designer's intent, rather than focusing on data
integrity, then the security definition works. 

In my mind I further characterise security as measures to thwart a
deliberate attack, while dependability usually considers random effects that
can affect a system's behaviour and as such the two concepts are
complementary.



Andy Ashworth, P.Eng 
System Safety Certifier
OLRT Constructors/Constructeurs
Confederation Line 
1600 Carling Ave. Ottawa, Ontario
Suite 450, PO Box 20, K1Z 1G3

Office: 613.916.6706
Cell: 613.314.6404
Email: andy.ashworth at ottawa-lrt.com





-----Original Message-----
From: systemsafety
[mailto:systemsafety-bounces at lists.techfak.uni-bielefeld.de] On Behalf Of
Christopher Johnson
Sent: April-20-16 11:03 AM
To: RICQUE Bertrand (SAGEM DEFENSE SECURITE) <bertrand.ricque at sagem.com>;
Peter Bernard Ladkin <ladkin at rvs.uni-bielefeld.de>;
systemsafety at lists.techfak.uni-bielefeld.de
Subject: Re: [SystemSafety] Does "reliable" mean "safe" and or "secure" or
neither?

I dont think this is appropriate any more.

Security here seems to imply conventional IT systems - most of the breaches
I work on in safety related SCADA/ICS applications focus on the consequent
loss of control which is not characterised either by concerns over data
integrity or confidentiality.
________________________________________
From: systemsafety [systemsafety-bounces at lists.techfak.uni-bielefeld.de] on
behalf of RICQUE Bertrand (SAGEM DEFENSE SECURITE)
[bertrand.ricque at sagem.com]
Sent: 20 April 2016 15:23
To: Peter Bernard Ladkin; systemsafety at lists.techfak.uni-bielefeld.de
Subject: Re: [SystemSafety] Does "reliable" mean "safe" and or "secure" or
neither?

I would stick to the Laprie taxonomy :

Dependability =  Availability + Reliability + Safety + Integrity(not the SIL
one, the true one) + Maintainability Security = Integrity + Confidentiality

Bertrand Ricque
Program Manager
Optronics and Defence Division
Sights Program
Mob : +33 6 87 47 84 64
Tel : +33 1 58 11 96 82
Bertrand.ricque at sagem.com

-----Original Message-----
From: systemsafety
[mailto:systemsafety-bounces at lists.techfak.uni-bielefeld.de] On Behalf Of
Peter Bernard Ladkin
Sent: Monday, April 18, 2016 8:21 PM
To: systemsafety at lists.techfak.uni-bielefeld.de
Subject: Re: [SystemSafety] Does "reliable" mean "safe" and or "secure" or
neither?

On 2016-04-18 18:25 , Chris Hills wrote:
> What is the current thinking?   Does "reliable" also infer safe or secure?

The system consists of the following.

You, tied up in a chair, fixed to the floor. Along with your nemesis, with a
rifle, who is pointing it at you, and is an excellent shot, and intends to
shoot. Heshe pulls the trigger.

If the rifle is reliable, the system is unsafe.

If the rifle is completely unreliable, the system is safe.

PBL
Prof. Peter Bernard Ladkin, Faculty of Technology, University of Bielefeld,
33594 Bielefeld, Germany Je suis Charlie
Tel+msg +49 (0)521 880 7319  www.rvs.uni-bielefeld.de





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