From 6345910ebf326f5778f67c124287b45e30e829f5 Mon Sep 17 00:00:00 2001
From: Charles Oliver Nutter <headius@headius.com>
Date: Tue, 11 Jun 2024 10:13:04 -0500
Subject: [PATCH] Implement Point#mul

---
 .../java/org/jruby/ext/openssl/PKeyEC.java    | 50 +++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/src/main/java/org/jruby/ext/openssl/PKeyEC.java b/src/main/java/org/jruby/ext/openssl/PKeyEC.java
index 47668444..bf86c60a 100644
--- a/src/main/java/org/jruby/ext/openssl/PKeyEC.java
+++ b/src/main/java/org/jruby/ext/openssl/PKeyEC.java
@@ -58,6 +58,8 @@
 import org.bouncycastle.jce.spec.ECNamedCurveParameterSpec;
 import org.bouncycastle.jce.spec.ECNamedCurveSpec;
 
+import org.bouncycastle.math.ec.ECAlgorithms;
+import org.bouncycastle.math.ec.ECCurve;
 import org.jruby.Ruby;
 import org.jruby.RubyArray;
 import org.jruby.RubyBoolean;
@@ -972,6 +974,7 @@ private boolean getPointAndGroup(ThreadContext context, IRubyObject groupOrPoint
 
             if ( groupOrPoint instanceof Group) {
                 this.group = (Group) groupOrPoint;
+                this.point = (ECPoint) ((Group) groupOrPoint).generator(context);
             } else {
                 throw runtime.newTypeError(groupOrPoint, _EC(runtime).getClass("Group"));
             }
@@ -1068,6 +1071,53 @@ public IRubyObject inspect() {
             return ObjectSupport.inspect(this, (List) Collections.singletonList(entry));
         }
 
+        @JRubyMethod(name = "mul", required = 1, optional = 2)
+        public IRubyObject mul(final ThreadContext context, final IRubyObject[] args) {
+            Ruby runtime = context.runtime;
+
+            org.bouncycastle.math.ec.ECPoint pointSelf, pointResult;
+
+            Group groupV = this.group;
+
+            Point result;
+
+            BigInteger bn_g = null;
+
+            ECCurve selfCurve = EC5Util.convertCurve(group.getCurve());
+            pointSelf = EC5Util.convertPoint(selfCurve, asECPoint());
+
+            result = new Point(runtime, getMetaClass());
+            result.initialize(context, groupV);
+            ECCurve resultCurve = EC5Util.convertCurve(result.group.getCurve());
+            pointResult = EC5Util.convertPoint(resultCurve, result.point);
+
+            int argc = Arity.checkArgumentCount(runtime, args, 1, 3);
+            IRubyObject arg1 = args[0], arg2 = args[1], arg3 = args[2];
+            if (!(arg1 instanceof RubyArray)) {
+                BigInteger bn = ((BN) arg1).getValue();
+
+                if (!arg2.isNil()) {
+                    bn_g = ((BN) arg2).getValue();
+                }
+
+                if (bn_g == null) {
+                    org.bouncycastle.math.ec.ECPoint mulPoint = ECAlgorithms.referenceMultiply(pointSelf, bn);
+                    result = new Point(runtime, EC5Util.convertPoint(mulPoint), result.group);
+                } else {
+                    org.bouncycastle.math.ec.ECPoint mulPoint = ECAlgorithms.sumOfTwoMultiplies(pointResult, bn_g, pointSelf, bn);
+                    result = new Point(runtime, EC5Util.convertPoint(mulPoint), result.group);
+                }
+
+                if (result == null) {
+                    newECError(runtime, "bad multiply result");
+                }
+            } else {
+                throw runtime.newNotImplementedError("calling #mul with arrays is not supported by this OpenSSL version");
+            }
+
+            return result;
+        }
+
         @Deprecated
         public IRubyObject initialize(final ThreadContext context, final IRubyObject[] args) {
             final int argc = Arity.checkArgumentCount(context.runtime, args, 1, 2);