Posterior vulnerability and leakage

Abstract

We recall from Chap. 3 that, given a secret X with prior distribution π, the “threat” to X can be measured as its g-vulnerability Vg(π) for a suitably chosen gain function g — where the choice of g reflects the circumstances, and the importance to us of the secret’s remaining undisclosed, and might vary depending on who “we” are and what adversary we are facing.