From b6c445639015fb8dbe4058006dac7a7affcc7437 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niels=20M=C3=B6ller?= <nisse@lysator.liu.se>
Date: Sat, 2 Aug 2014 21:41:03 +0200
Subject: [PATCH] Fixed equations for Montgomery->Edwards transformation.
---
misc/ecc-formulas.tex | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/misc/ecc-formulas.tex b/misc/ecc-formulas.tex
index 36c15227..46225066 100644
--- a/misc/ecc-formulas.tex
+++ b/misc/ecc-formulas.tex
@@ -127,7 +127,7 @@ mapping $P = (x,y)$ to $P' = (u, v)$, as follows.
that $x^2 + bx + 1 = 0$, or $(x + b/2)^2 = (b/2)^2 - 1$, which also
isn't a quadratic residue). The correspondence is then given by
\begin{align*}
- u &= \sqrt{b} \, x / y \\
+ u &= \sqrt{b+2} \, x / y \\
v &= (x-1) / (x+1)
\end{align*}
\end{itemize}
@@ -135,7 +135,7 @@ mapping $P = (x,y)$ to $P' = (u, v)$, as follows.
The inverse transformation is
\begin{align*}
x &= (1+v) / (1-v) \\
- y &= \sqrt{b} x / u
+ y &= \sqrt{b+2} x / u
\end{align*}
If the Edwards coordinates are represented using homogeneous
coordinates, $u = U/W$ and $v = V/W$, then
--
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