From adf7433476b63267177c0a50da394de2838404eb Mon Sep 17 00:00:00 2001
From: Peter Dettman <peter.dettman@bouncycastle.org>
Date: Sun, 8 Feb 2015 21:36:03 +0700
Subject: Port of WNaf precomp optimization from Java

---
 crypto/src/math/ec/ECAlgorithms.cs | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

(limited to 'crypto/src/math/ec/ECAlgorithms.cs')

diff --git a/crypto/src/math/ec/ECAlgorithms.cs b/crypto/src/math/ec/ECAlgorithms.cs
index 3c911b173..a1349a9e0 100644
--- a/crypto/src/math/ec/ECAlgorithms.cs
+++ b/crypto/src/math/ec/ECAlgorithms.cs
@@ -116,6 +116,11 @@ namespace Org.BouncyCastle.Math.EC
         }
 
         public static void MontgomeryTrick(ECFieldElement[] zs, int off, int len)
+        {
+            MontgomeryTrick(zs, off, len, null);
+        }
+
+        public static void MontgomeryTrick(ECFieldElement[] zs, int off, int len, ECFieldElement scale)
         {
             /*
              * Uses the "Montgomery Trick" to invert many field elements, with only a single actual
@@ -133,7 +138,14 @@ namespace Org.BouncyCastle.Math.EC
                 c[i] = c[i - 1].Multiply(zs[off + i]);
             }
 
-            ECFieldElement u = c[--i].Invert();
+            --i;
+
+            if (scale != null)
+            {
+                c[i] = c[i].Multiply(scale);
+            }
+
+            ECFieldElement u = c[i].Invert();
 
             while (i > 0)
             {
-- 
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