Maximal Guesswork Leakage
Gowtham R. Kurri, Malhar Managoli, Vinod M. Prabhakaran
TL;DR
The paper develops a guessing-based framework for information leakage, introducing maximal guesswork leakage and its pointwise and oblivious variants. By exploiting Rényi information measures, it derives closed-form expressions for several leakage notions, including a complete solution for the binary erasure source, and reveals a tight connection to differential privacy and maximal $\alpha$-leakage. It also establishes an operational interpretation of oblivious maximal $\rho$-guesswork leakage in terms of Arimoto information and channel capacity, while identifying sharp local bounds via the pointwise and pw-oblivious forms. The results bridge guessing frameworks with privacy notions, providing precise characterizations and guiding principles for leakage analysis in secure data releases and privacy-preserving systems.
Abstract
We introduce the study of information leakage through \emph{guesswork}, the minimum expected number of guesses required to guess a random variable. In particular, we define \emph{maximal guesswork leakage} as the multiplicative decrease, upon observing $Y$, of the guesswork of a randomized function of $X$, maximized over all such randomized functions. We also study a pointwise form of the leakage which captures the leakage due to the release of a single realization of $Y$. We also study these two notions of leakage with oblivious (or memoryless) guessing. We obtain closed-form expressions for all these leakage measures, with the exception of one. Specifically, we are able to obtain closed-form expression for maximal guesswork leakage for the binary erasure source only; deriving expressions for arbitrary sources appears challenging. Some of the consequences of our results are -- a connection between guesswork and differential privacy and a new operational interpretation to maximal $α$-leakage in terms of guesswork.
