1 files changed, 26 insertions, 0 deletions
diff --git a/core/src/main/java/org/spongycastle/math/ec/AbstractECMultiplier.java b/core/src/main/java/org/spongycastle/math/ec/AbstractECMultiplier.java
new file mode 100644
index 00000000..e4dee6dd
--- /dev/null
+++ b/core/src/main/java/org/spongycastle/math/ec/AbstractECMultiplier.java
@@ -0,0 +1,26 @@
+package org.spongycastle.math.ec;
+
+import java.math.BigInteger;
+
+public abstract class AbstractECMultiplier implements ECMultiplier
+{
+    public ECPoint multiply(ECPoint p, BigInteger k)
+    {
+        int sign = k.signum();
+        if (sign == 0 || p.isInfinity())
+        {
+            return p.getCurve().getInfinity();
+        }
+
+        ECPoint positive = multiplyPositive(p, k.abs());
+        ECPoint result = sign > 0 ? positive : positive.negate();
+
+        /*
+         * Although the various multipliers ought not to produce invalid output under normal
+         * circumstances, a final check here is advised to guard against fault attacks.
+         */
+        return ECAlgorithms.validatePoint(result);
+    }
+
+    protected abstract ECPoint multiplyPositive(ECPoint p, BigInteger k);
+}