Add EC_POINT_add support

2 files changed, 45 insertions, 0 deletions

diff --git a/ext/openssl/ossl_pkey_ec.c b/ext/openssl/ossl_pkey_ec.c
index 8bb61124..fc2bc6c8 100644
--- a/ext/openssl/ossl_pkey_ec.c
+++ b/ext/openssl/ossl_pkey_ec.c
@@ -1564,6 +1564,34 @@ ossl_ec_point_to_octet_string(VALUE self, VALUE conversion_form)
 
 /*
  * call-seq:
+ *   point.add(point) => point
+ *
+ * Performs elliptic curve point addition.
+ */
+static VALUE ossl_ec_point_add(VALUE self, VALUE other)
+{
+    EC_POINT *point_self, *point_other, *point_result;
+    const EC_GROUP *group;
+    VALUE group_v = rb_attr_get(self, id_i_group);
+    VALUE result;
+
+    GetECPoint(self, point_self);
+    GetECPoint(other, point_other);
+    GetECGroup(group_v, group);
+
+    result = rb_obj_alloc(cEC_POINT);
+    ossl_ec_point_initialize(1, &group_v, result);
+    GetECPoint(result, point_result);
+
+    if (EC_POINT_add(group, point_result, point_self, point_other, ossl_bn_ctx) != 1) {
+        ossl_raise(eEC_POINT, "EC_POINT_add");
+    }
+
+    return result;
+}
+
+/*
+ * call-seq:
  *   point.mul(bn1 [, bn2]) => point
  *   point.mul(bns, points [, bn2]) => point
  *
@@ -1786,6 +1814,7 @@ void Init_ossl_ec(void)
 /* all the other methods */
 
     rb_define_method(cEC_POINT, "to_octet_string", ossl_ec_point_to_octet_string, 1);
+    rb_define_method(cEC_POINT, "add", ossl_ec_point_add, 1);
     rb_define_method(cEC_POINT, "mul", ossl_ec_point_mul, -1);
 
     id_i_group = rb_intern("@group");
diff --git a/test/test_pkey_ec.rb b/test/test_pkey_ec.rb
index 95b5a642..c4eb2ead 100644
--- a/test/test_pkey_ec.rb
+++ b/test/test_pkey_ec.rb
@@ -289,6 +289,22 @@ class OpenSSL::TestEC < OpenSSL::PKeyTestCase
     assert_equal true, point.on_curve?
   end
 
+  def test_ec_point_add
+    group = OpenSSL::PKey::EC::Group.new(:GFp, 17, 2, 2)
+    group.point_conversion_form = :uncompressed
+    gen = OpenSSL::PKey::EC::Point.new(group, B(%w{ 04 05 01 }))
+    group.set_generator(gen, 19, 1)
+
+    point_a = OpenSSL::PKey::EC::Point.new(group, B(%w{ 04 06 03 }))
+    point_b = OpenSSL::PKey::EC::Point.new(group, B(%w{ 04 10 0D }))
+
+    result = point_a.add(point_b)
+    assert_equal B(%w{ 04 0D 07 }), result.to_octet_string(:uncompressed)
+
+    assert_raise(TypeError) { point_a.add(nil) }
+    assert_raise(ArgumentError) { point_a.add }
+  end
+
   def test_ec_point_mul
     begin
       # y^2 = x^3 + 2x + 2 over F_17