From 29fa45446b15d69dedd1fcf01cc65292a9ac120f Mon Sep 17 00:00:00 2001 From: Christian Grothoff Date: Tue, 25 Oct 2016 15:23:46 +0200 Subject: avoid introducing G twice --- doc/paper/taler.tex | 21 ++++++++++----------- 1 file changed, 10 insertions(+), 11 deletions(-) (limited to 'doc') diff --git a/doc/paper/taler.tex b/doc/paper/taler.tex index 0b5bcc60b..54e4c0e13 100644 --- a/doc/paper/taler.tex +++ b/doc/paper/taler.tex @@ -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 -- cgit v1.2.3