An Obsession with Definitions

摘要

Many people seem to think that cryptography is all about creating and analyzing cryptographic schemes. This view ignores the centrality of definitions in shaping the character of the field. More than schemes or their analysis, it is definitions that most occupy my thoughts. In this paper, written to accompany an invited talk at Latincrypt 2017, I try to explain my own fascination with definitions. I outline a few of the definitions I've recently worked on—garbling schemes, online AE, and onion encryption—and provide some general advice and comments about the definitional enterprise.