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@@ -226,7 +226,48 @@ that in the Standard Model, blind signature schemes need to have $>3$ moves.
 
 
 \section{Literature Survey}
+\subsection{Chaum Blind Signatures}
+Reference: \cite{chaum1983}.  Only defines blind signatures and their application to ``untraceable`` payments.
 
+\subsection{Chaum with Offline Spending}
+Reference: \cite{chaum1990}.  Introduces offline double spending detection.
+
+\subsection{HINDE}
+Reference:  Unpublished, there used to be some references on a mailing list, but they seem to be gone.
+
+\subsection{Compact E-Cash}
+Reference: \cite{camenisch2005}.  Allows to withdraw $2^\ell$ coins in $O(\ell)$.  Either the whole
+$2^\ell$ coins must be spent at once, or all coins must be spent separately.
+
+\subsection{Divisible E-Cash Made Practical}
+Reference: \cite{canard2015divisible}.  Introduces a different coin structure
+where there is one global tree and all coins are put on that skeleton.
+Requires trusted setup that endangers anonymity.
+
+\subsection{Scalable Divisible E-Cash}
+Reference: \cite{canard2015scalable}.  Improves the spending protocol of ``Divisible E-Cash Made Practical'', so that the
+bank only has to store serial numbers of coins that are actually spent and not ``fake'' serial numbers that
+are a side-effect of the crypto used.
+
+
+\subsection{Practical Divisible E-Cash}
+Reference: \cite{maertens2015} (unpublished).  Parallel development to ``Divisible E-Cash Made Practical'', uses
+accumulators and not the global structure (less trusted setup).
+
+
+\subsection{Cut Down The Tree}
+Reference: \cite{pointcheval2017}.  Keeps some of the ideas of \cite{canard2015divisible} but removes the tree structure.
+Currently considered state of the art.
+
+\section{Things we don't care about}
+
+Offline spending:  Introduces brittleness (when backing up), since users might accidentally double spend.
+Enforcement is hard to guarantee.  Some schemes even disclose all transaction of a user on double spending.
+
+Transferability:  Means that coins can be exchanged safely without being recorded in the exchange,
+goes against income transparency.
+
+``Fairness'': Means that a threshold of authorities can de-anonymize a user.  Too much potential for abuse.