Wednesday, 19 February 2014

Privacy Engineering and Checklists

A colleague brought to my attention a publication from the PbD community on the subject of privacy engineering [1]. Overall the paper I think gives a good introduction into what privacy engineering could be. I say "could by" because PE needs a huge amount of work, from all angles including the deeper mathematical basis as well as basic, software engineering, process, management etc. The current definition given above is:
"...privacy engineering is the discipline of understanding how to include privacy as a non-functional requirement in systems engineering. While privacy may also appear as a functional requirement of a given system (such as the TOR anonymity system), for most systems, privacy is ancillary to the primary purpose
of the system."
Not bad but quite a few of these non-functional requirements become very awkward functional requirements very quickly as the development proceeds.

The part that particular interests me is regarding checklists:
"The checklist approach to privacy protection has been debated. Checklists have become important safety elements in airplane and medical procedures and are quite common in security auditing. However, their utility for privacy remains questionable. It might be possible to design privacy checklists for frequent and standardized use cases, but the breadth of potential projects makes a standard checklist for everything an unlikely tool."
The above cites an earlier article on this blog about moments that changed how particular industries approached safety. There exists possibly a better article on checklists which explains the rationale behind their use.

Partly the paragraph is correct, the utility of checklists in privacy needs to be established, but, given what a checklist is and what is should be designed to achieve is independent of the area. Indeed the next statement that it might be possible to design privacy checklists for frequent and standardised use cases is exactly the cases where checklists do come into their own. Often repeated, critical phases of design - patterns if you like - are the areas where mistakes are frequently made; things are forgotten etc.

There are NO standard checklists - at least not for the expected usages hinted in the paper. If we compare with the WHO surgical checklists which work in similar, very open, high volatility environments there is a capitalised statement on the bottom of the checklist:
Ignore at your peril.

Indeed the checklist in privacy WILL NOT give you a standardised approach NOR will it give you the tool for checking your system. It WILL give you a list of things that you should remember to complete at particular relevant points. A checklist should be independent of your processes and partially independent of what ever tooling and techniques are being applied to the problem at hand. Furthermore, if the various items on a checklist are not completed it is not an indication that the process can not continue but rather a warning that important facts might not have been established.

For example, on aircraft take-off there is a checklist item for the setting of flaps. This item may not necessarily specify the specific flap settings as this might vary by many conditions and the item can be ignored (and the flaps not set) and take-off can proceed - though this might be a particularly bad idea as in the Spanair Flight 5022 case.

Interestingly in the paper checkilsts seem to be positioned against privacy impact assessments. I could better imagine that in the privacy checklist an entry "PIAs performed" is included, possibly with further qualifications as necessary. It might be considered that such an entry is superfluous - who would forget to do the PIAs? I agree, pilots would never forget to lower flaps prior to take-off or a surgeon forget to check that the he is set up for the correct procedure to be performed....

Maybe the term checklist isn't the best and this is where some confusion arises. At Great Ormond Street hospital the term "Aide-Mémoire" is used to reflect the function of the checklist and avoid the confusion with the "tick-box mentality" and confusion with process.

Privacy is a very wide area without well established and standardised use cases or at least not at the level of detail that say aviation is as is pointed out in the paper we lack. Indeed it is this lack of standardisation that makes the integration of checklists or aide-mémoires much more important.

Some of our experiences with checklists in this area can be found in an earlier posting entitled: Flying Planes, Surgey and Privacy. [2]


[1] Shapiro, Cronk, Cavoukian (2014) Privacy Engineering: Proactively Embedding Privacy, by Design.

[2] Ian Oliver, Tomi Kulmala (2013) Flying planes, Surgery and Privacy.

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