%% LyX 1.2 created this file.  For more info, see http://www.lyx.org/.
%% Do not edit unless you really know what you are doing.
\documentclass[english]{article}
\usepackage[T1]{fontenc}
\usepackage[latin1]{inputenc}

\makeatletter

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% LyX specific LaTeX commands.
\providecommand{\LyX}{L\kern-.1667em\lower.25em\hbox{Y}\kern-.125emX\@}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% User specified LaTeX commands.
\usepackage{ae,aecompl}
\usepackage{babel}
\makeatother
\begin{document}

\title{Digital Cash}

\maketitle
This project is based on the protocol number 4, described in {[}SCHN96{]},
p. 142. Basically this protocol implements an electronic cash system,
in which the digital cash cannot be copied or reused more than once
and the privacy of the customer's identity is guaranteed. 


\part*{Implementation: }

The system allows money transaction between three parties: Customer,
Merchant and Bank. The electronic cash (ecash) used during these transactions
is a file which contains:

\begin{itemize}
\item the amount of the transaction involved
\item a uniqueness string number
\item identity strings which contain the identity of the customer (this
information remains secret unless the customer tries to use the ecash
illicitly more than once); 
\item bank's signature (before the customer can use the ecash) The services
provided for each party is described as follows:
\end{itemize}

\part*{Customer}

\begin{itemize}
\item generates N orders for each money order the customer wants to make
and assigns a different random uniqueness string number for each of
the N ecash money orders
\item implements the secret splitting and bit commitment protocols used
to generate the identity strings that describe the customer's name,
address and any other piece of identifying information that the bank
wants to see. 
\item implements a blind signature protocol for all N money orders 
\item automatically complies to reveal the half of the identity string chosen
by the merchant 
\end{itemize}

\part*{Merchant }

\begin{itemize}
\item verification of the legitimacy of the bank's signature 
\item random generator of the selector string, which determines the half
of the identity string the customer is required to reveal
\end{itemize}

\part*{Bank }

\begin{itemize}
\item random choice of 1 out of N money orders sent by the customer to remain
unopened 
\item an algorithm that certifies that all the N-1 money orders have been
filled with valid information
\item a procedure to certify that the orders received from merchants have
not been used previously and storage of the uniqueness string and
identity strings of the orders in a database file
\item Appropriate measures against reuse of the ecash \end{itemize}

\end{document}
