1 files changed, 30 insertions, 0 deletions
diff --git a/core/src/main/java/org/spongycastle/math/ec/NafL2RMultiplier.java b/core/src/main/java/org/spongycastle/math/ec/NafL2RMultiplier.java
new file mode 100644
index 00000000..b2aac42c
--- /dev/null
+++ b/core/src/main/java/org/spongycastle/math/ec/NafL2RMultiplier.java
@@ -0,0 +1,30 @@
+package org.spongycastle.math.ec;
+
+import java.math.BigInteger;
+
+/**
+ * Class implementing the NAF (Non-Adjacent Form) multiplication algorithm (left-to-right).
+ */
+public class NafL2RMultiplier extends AbstractECMultiplier
+{
+    protected ECPoint multiplyPositive(ECPoint p, BigInteger k)
+    {
+        int[] naf = WNafUtil.generateCompactNaf(k);
+
+        ECPoint addP = p.normalize(), subP = addP.negate();
+
+        ECPoint R = p.getCurve().getInfinity();
+
+        int i = naf.length;
+        while (--i >= 0)
+        {
+            int ni = naf[i];
+            int digit = ni >> 16, zeroes = ni & 0xFFFF;
+
+            R = R.twicePlus(digit < 0 ? subP : addP);
+            R = R.timesPow2(zeroes);
+        }
+
+        return R;
+    }
+}