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Small Ring-LWE comments

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Jeff Burdges 2016-05-02 10:10:29 +02:00
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doc/paper/postquantum_melt.tex
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@ -342,9 +342,9 @@ pay to withdraw it.
\subsection{Withdrawal}\label{subsec:withdrawal} \subsection{Withdrawal}\label{subsec:withdrawal}
In Taler, we may address tax fraud on initial withdrawal by turning In Taler, we may address tax fraud on initial withdrawal by turning
withdrawal into a refresh from a pseudo-coin $(C,\Mu)$ consisting of withdrawal into a refresh from a pseudo-coin $(C,\Mu)$ in which
the user's reserve key \cite[??]{Taler} and $C$ is the user's reserve key \cite[??]{Taler} and
a post-quantum public key $\Mu$. $\Mu$ s a post-quantum public key kept with $C$.
We see below however that our public key algorithm has very different We see below however that our public key algorithm has very different
security requirements in this case, impacting our algorithm choices. security requirements in this case, impacting our algorithm choices.
@ -485,8 +485,16 @@ refreshing change.
\section{Hash and Ring-LWE hybrid} \section{Hash and Ring-LWE hybrid}
We noted above in \S\ref{subsec:withdrawal} that exchange might We noted in \S\ref{subsec:withdrawal} above that exchange might
require a refresh-like operation when coins are initially withdrawn. require that initial withdrawals employs a refresh-like operation.
In this scenarion, we refresh from a pseudo-coin $(C,\Mu)$ where
$C$ is the user's reserve key \cite[??]{Taler} and
$\Mu$ s a post-quantum public key kept with $C$.
As a result, our hash-based scheme should increase the security
paramater $\delta$ to allow a query for every withdrawal operation.
Instead, we propose using a Merkle tree of Alice side Ring-LWE keys,
while continuing to invent the Bob side Ring-LWE key.
... ...
% Use birthday about on Alice vs Bob keys % Use birthday about on Alice vs Bob keys