Processing Data to Protect Data: Resolving the Breach Detection Paradox

Most privacy laws contain two obligations: that processing of personal data must be minimised, and that security breaches must be detected and mitigated as quickly as possible. These two requirements appear to conflict, since detecting breaches requires additional processing of logfiles and other personal data to determine what went wrong. Fortunately Europe’s General Data Protection Regulation (GDPR) – considered the strictest such law – recognises this paradox and suggests how both requirements can be satisfied. This paper assesses security breach detection in the light of the principles of purpose limitation and necessity, finding that properlyconducted breach detection should satisfy both principles. Indeed the same safeguards that are required by data protection law are essential in practice for breach detection to achieve its purpose. The increasing use of automated breach detection is then examined, finding opportunities to further strengthen these safeguards as well as those that might be required by the GDPR provisions on profiling and automated decision-making. Finally we consider how processing for breach detection relates to the context of providing and using on-line services concluding that, far from being paradoxical, it should be expected and welcomed by regulators and (2020) 17:2 SCRIPTed 197 198 all those whose data may be stored in networked computers.