Paper 2017/1220

Off-line Digital Cash Schemes Providing Unlinkability, Anonymity and Change

Lynn Batten and Xun Yi

Abstract

Several ecash systems have been proposed in the last twenty years or so,each offering features similar to real cash. One feature which to date has not been provided is that of a payee giving change to a payer for an e-coin in an off-line setting. In this paper, we indicate how an off-line ecash system can solve the change-giving problem. In addition, our protocol offers the usual expected features of anonymity and unlinkability of the payer, but can reveal the identity of an individual who illegally tries to spend ecash twice.

Note: We were asked to use capitals only on first letters.