Cavounidis, C., "Perfect Secrecy in the Wild: A Characterization"

Title: "Perfect Secrecy in the Wild: A Characterization"  
(co-authored with Massimiliano Furlan & Alkis Georgiadis-Harris)

Speaker: Associate Professor Costas Cavounidis, University of Warwick

Host:  Assistant Professor Efthymios Athanasiou, Department of Economics, Athens University of Economics and Business

Time: 15.30 -17.00

Room:  76, Patission Str., Antoniadou Wing, 3rd floor, Room A36

Abstract: Alice wishes to reveal the state X to Bob, if he knows some other information Y also known to her. If Bob does not, she wishes to reveal nothing about X at all. When can Alice accomplish this? We provide a simple necessary and sufficient condition on the joint distribution of X and Y. Shannon's result on the perfect secrecy of the one-time pad follows as a special case. Further, we characterize what information about X can be revealed to Bob when he knows Y, a characterization valid even when our main condition fails. We discuss implications for algorithmic fairness and digital privacy regulation generally.