Missed from previous commit

1 files changed, 23 insertions, 0 deletions

diff --git a/core/src/main/java/org/bouncycastle/math/ec/WNafUtil.java b/core/src/main/java/org/bouncycastle/math/ec/WNafUtil.java
index e1868f4d..7db5c1de 100644
--- a/core/src/main/java/org/bouncycastle/math/ec/WNafUtil.java
+++ b/core/src/main/java/org/bouncycastle/math/ec/WNafUtil.java
@@ -283,6 +283,29 @@ public abstract class WNafUtil
         return wnaf;
     }
 
+    public static int getNafWeight(BigInteger k)
+    {
+        if (k.signum() == 0)
+        {
+            return 0;
+        }
+
+        BigInteger _3k = k.shiftLeft(1).add(k);
+        BigInteger diff = _3k.xor(k);
+
+        int highBit = _3k.bitLength() - 1, length = 1;
+        for (int i = 1; i < highBit; ++i)
+        {
+            if (diff.testBit(i))
+            {
+                ++length;
+                ++i;
+            }
+        }
+
+        return length;
+    }
+
     public static WNafPreCompInfo getWNafPreCompInfo(ECPoint p)
     {
         return getWNafPreCompInfo(p.getCurve().getPreCompInfo(p, PRECOMP_NAME));