1 files changed, 37 insertions, 0 deletions
diff --git a/libraries/spongycastle/core/src/main/java/org/spongycastle/math/ec/ReferenceMultiplier.java b/libraries/spongycastle/core/src/main/java/org/spongycastle/math/ec/ReferenceMultiplier.java
new file mode 100644
index 000000000..6c03173f9
--- /dev/null
+++ b/libraries/spongycastle/core/src/main/java/org/spongycastle/math/ec/ReferenceMultiplier.java
@@ -0,0 +1,37 @@
+package org.spongycastle.math.ec;
+
+import java.math.BigInteger;
+
+public class ReferenceMultiplier extends AbstractECMultiplier
+{
+    /**
+     * Simple shift-and-add multiplication. Serves as reference implementation
+     * to verify (possibly faster) implementations in
+     * {@link org.spongycastle.math.ec.ECPoint ECPoint}.
+     * 
+     * @param p The point to multiply.
+     * @param k The factor by which to multiply.
+     * @return The result of the point multiplication <code>k * p</code>.
+     */
+    protected ECPoint multiplyPositive(ECPoint p, BigInteger k)
+    {
+        ECPoint q = p.getCurve().getInfinity();
+        int t = k.bitLength();
+        if (t > 0)
+        {
+            if (k.testBit(0))
+            {
+                q = p;
+            }
+            for (int i = 1; i < t; i++)
+            {
+                p = p.twice();
+                if (k.testBit(i))
+                {
+                    q = q.add(p);
+                }
+            }
+        }
+        return q;
+    }
+}