The banksys signature transport (BST) protocol

Abstract

This document describes a new cryptographic protocol that allows the efficient authentication of an unlimited amount of data coming from an IC Card by an off-line terminal where the IC Card’s cryptographic capability is limited to computing one-way functions and MACs. The authentication of the IC Card and its data are based on a Challenge-Response protocol using one-way functions. The protocol is especially suited for use in off-line electronic purse payments in an interoperable environment, where sharing of secret keys between different institutions is not allowed. It is also suited for off-line debit/credit payment applications. The protocol, when applied for purse payments or debit/credit allows transaction timings of the order of 1 second if implemented on currently mass-produced IC Cards.