Re: [SystemSafety] Statistical Assessment of SW With Deliberate Unreliability for a SIL requirement

From: Martyn Thomas < >
Date: Wed, 21 Jan 2015 16:53:22 +0000


This example leads into the wider issue of the assessment of security as part of safety certification.

Such statistical analysis is probably based on assumptions that would be invalid if you consider a hostile security environment.


On 21/01/2015 10:30, Peter Bernard Ladkin wrote:
> I am working with others on a reformulation of IEC 61508 Part 7 Annex D, on the statistical
> assessment of software presented with black-box functionality.
> Rainer Faller brought up an interesting example. He has seen SW which is proposed to be used in a
> safety-related application, which has a Safety Requirements Specification (SRS) in that application,
> and which has a "Debug/Maintenance" mode, triggered by a specific input sequence known to the SW
> developer of course, but not necessarily to the system developer who wishes to use it in the new
> safety-related application.
> Can such SW be presented as "black box" with statistical evidence of its fitness for purpose, and
> accepted for use based on the statistical assessment?
> I've written a White Paper on the case, RVS White Paper 8, available at
> Prof. Peter Bernard Ladkin, Faculty of Technology, University of Bielefeld, 33594 Bielefeld, Germany
> Je suis Charlie
> Tel+msg +49 (0)521 880 7319
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systemsafety_at_xxxxxx Received on Wed Jan 21 2015 - 17:53:30 CET

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