Thread by @RDBinns

Thread summary of new paper (at #CHI2021): "Exploring Design and Governance Challenges in the Development of Privacy-Preserving Computation" w/ Nitin Agrawal, @emax, Kim Laine & @Nigel_Shadbolt arxiv.org/abs/2101.08048

New techniques for 'privacy-preserving computation'(PPC) (inc. homomorphic encryption, secure multi-party computation, differential privacy) present novel questions for HCI, from usability and mental models, to the values they embed/elide, & their social + political implications

We interviewed experts working on PPC, from academia, industry, law & policy, and design, and identified challenges in moving from theory to practice, interdisciplinarity translation, developer usability, explanation, governance and accountability

PPCs challenge typical approaches to abstraction and complexity; hiding implementation details behind libraries and APIs makes it difficult for developers to optimise through engineering 'tricks', and to reason sensibly about the parameters that determine security guarantees

While PPCs aim to protect 'privacy', we found this unpacked in subtly different ways, from human rights to corporate secrets and regulatory compliance. Several pointed to challenges in explaining and justifying these systems to decision-makers, stakeholders, and society at large

In addition to studying 'acceptability' for end-users / data subjects, it is equally important to consider the plurality of different actors and contexts through which values like privacy will be understood, traded-off, and embedded in them (or not)

PPC techniques have an aura of mystique. Their construction is more craft than science, and their inner workings and risks can't be easily communicated. There's a risk that they become not just technical but technocratic solutions (we call 'privacy-enhancing technocracy')

Discourse around PPCs may also function to distract us from the ways computation might reinforce existing problematic power structures, or redefine them as ‘privacy’ problems, so that PPCs can be positioned as the solution, while leaving those structures intact