avoid introducing G twice

This commit is contained in:
Christian Grothoff 2016-10-25 15:23:46 +02:00
parent 176078bb8c
commit 29fa45446b

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@ -796,17 +796,16 @@ denomination $K$ is melted to obtain a fresh coin $\widetilde{C}$
with the same denomination. In practice, Taler uses a natural
extension where multiple fresh coins are generated a the same time to
enable giving precise change matching any amount.
In the protocol, $\kappa \ge 3$ is a security parameter for the
cut-and-choose part of the protocol and $G$ is the
generator of the elliptic curve.
We note that $\kappa = 3$ is actually perfectly sufficient in most
cases in practice, as the cut-and-choose protocol does not need to
provide cryptographic security: If the maximum applicable tax is less
than $\frac{2}{3}$, then detecting $\kappa = 3$ ensures that cheating
results in a negative return on average as $\kappa - 1$ out of
$\kappa$ attempts to cheat are detected. This makes the use of
cut-and-choose practical and efficient in this context.
In the protocol, $\kappa \ge 2$ is a security parameter for the
cut-and-choose part of the protocol. $\kappa = 3$ is actually
perfectly sufficient in most cases in practice, as the cut-and-choose
protocol does not need to provide cryptographic security: If the
maximum applicable tax is less than $\frac{2}{3}$, then detecting
$\kappa = 3$ ensures that cheating results in a negative return on
average as $\kappa - 1$ out of $\kappa$ attempts to cheat are
detected. This makes the use of cut-and-choose practical and
efficient in this context.
% FIXME: I'm explicit about the rounds in postquantum.tex