Trustworthy Systems

The Laplace mechanism has optimal utility for differential privacy over continuous queries


Natasha Fernandes, Annabelle McIver and Carroll Morgan

    School of Computer Science and Engineering
    Sydney 2052, Australia


The study of quantitative risk in security systems is often based around complex and subtle mathematical ideas involving probabilities. The notations for these ideas can pose a communication barrier between collaborating researchers even when those researchers are working within a similar framework. This paper describes the use of geometrical representation and reasoning as a way to share ideas using the minimum of notation so as to build intuition about what kinds of properties might or might not be true. We describe a faithful geometrical setting for the channel model of quantitative information flow (QIF) and demonstrate how it can facilitate "proofs without words" for problems in the QIF setting.

Keywords: Geometry, Quantitative Information Flow, Proof, Explainability, Privacy

BibTeX Entry

    author           = {Natasha Fernandes and Annabelle McIver and Carroll Morgan},
    journal          = {36th Annual ACM/IEEE Symposium on Logic in Computer Science (LICS)},
    pages            = {1-12},
    paperurl         = {},
    title            = {The {Laplace} Mechanism has optimal utility for differential privacy over continuous queries},
    year             = {2021}