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: Fixed equations for Montgomery->Edwards transformation.

---
 misc/ecc-formulas.tex | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

(limited to 'misc')

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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