Paper 2025/1951 Original: eprint.iacr.org/2025/1951 ↗

What is Cryptography Hiding from Itself?

Abstract

The European Commission's 2022 proposal for a regulation on child sexual abuse material, popularly labelled ChatControl, obliges online services to detect, report, and remove prohibited content, through client-side scanning. This paper examines the proposal as a case of undone science in computer security ethics: a domain where technical feasibility and rights-compatibility questions remain systematically underexplored. Combining legal analysis with philosophy of technology, the paper argues that client-side scanning transforms end-to-end encryption from a right to secrecy into a conditional privilege of use. By integrating Isaiah Berlin's concept of negative liberty, Langdon Winner’s account of the politics of artifacts, and David Hess’s notion of undone science, the analysis traces how design choices become moral constraints. The discussion situates the European debate within broader concerns about proportionality, epistemic selectivity, and the governance of digital infrastructures. Ultimately, the study shows that the controversy over ChatControl is not only about privacy or child protection but about the epistemic norms that define what counts as legitimate technological knowledge.