De re/de dicto distinction: a logicians' perspective on data anonymity

Junli Jiang, Pavel Naumov

Abstract: The distinction between de re (of the thing) and de dicto (of what is said) readings of sentences has long been the topic of studies in logic and philosophy of language. The article proposes to apply these concepts to anonymity. It argues that, in the proposed setting, de dicto knowledge preserves anonymity, while de re knowledge does not. The article also considers a third, “overt,” form of knowledge. The main technical result is a sound and complete logical system that captures the interplay between a data traceability expression and the de re, de dicto, and overt knowledge modalities. The article also shows that the three knowledge modalities are not definable through each other even in the presence of the traceability expression.