From 10ebb31d49655727ceb15e135420118d2b2ff8b8 Mon Sep 17 00:00:00 2001
From: Guten Ye <ywzhaifei@gmail.com>
Date: Wed, 21 Nov 2018 13:25:08 +0800
Subject: [PATCH] Added derivation_to_scalar

---
 src/serial_bridge_index.cpp | 20 ++++++++++++++++++++
 src/serial_bridge_index.hpp |  1 +
 test/test_all.cpp           | 24 ++++++++++++++++++++++++
 3 files changed, 45 insertions(+)

diff --git a/src/serial_bridge_index.cpp b/src/serial_bridge_index.cpp
index c340b98..4160e9c 100644
--- a/src/serial_bridge_index.cpp
+++ b/src/serial_bridge_index.cpp
@@ -761,3 +761,23 @@ string serial_bridge::derive_subaddress_public_key(const string &args_string)
 	//
 	return ret_json_from_root(root);
 }
+string serial_bridge::derivation_to_scalar(const string &args_string)
+{
+	boost::property_tree::ptree json_root;
+	if (!parsed_json_root(args_string, json_root)) {
+		// it will already have thrown an exception
+		return error_ret_json_from_message("Invalid JSON");
+	}
+	crypto::key_derivation derivation;
+	if (!epee::string_tools::hex_to_pod(json_root.get<string>("derivation"), derivation)) {
+		return error_ret_json_from_message("Invalid 'derivation'");
+	}
+	std::size_t output_index = stoul(json_root.get<string>("output_index"));
+	crypto::ec_scalar scalar = AUTO_VAL_INIT(scalar);
+	crypto::derivation_to_scalar(derivation, output_index, scalar);
+	boost::property_tree::ptree root;
+	root.put(ret_json_key__generic_retVal(), epee::string_tools::pod_to_hex(scalar));
+	//
+	return ret_json_from_root(root);
+}
+
diff --git a/src/serial_bridge_index.hpp b/src/serial_bridge_index.hpp
index f63570f..f9a9f4d 100644
--- a/src/serial_bridge_index.hpp
+++ b/src/serial_bridge_index.hpp
@@ -69,6 +69,7 @@ namespace serial_bridge
 	string generate_key_derivation(const string &args_string);
 	string derive_public_key(const string &args_string);
 	string derive_subaddress_public_key(const string &args_string);
+	string derivation_to_scalar(const string &args_string);
 	string decodeRct(const string &args_string);
 	string decodeRctSimple(const string &args_string);
 }
diff --git a/test/test_all.cpp b/test/test_all.cpp
index 6ea7626..65c713b 100644
--- a/test/test_all.cpp
+++ b/test/test_all.cpp
@@ -1091,6 +1091,30 @@ BOOST_AUTO_TEST_CASE(bridge__mainnet_pubKeyDerivations)
 	}
 }
 //
+BOOST_AUTO_TEST_CASE(bridged__derivation_to_scalar)
+{
+	using namespace serial_bridge;
+	//
+	boost::property_tree::ptree root;
+	root.put("derivation", "7a4c13a037d4bd2a7dd99a8c24669e9e04ca4e8a90e5b6703e88e87ad51c1849");
+	root.put("output_index", "1");
+	//
+	auto ret_string = serial_bridge::derivation_to_scalar(args_string_from_root(root));
+	stringstream ret_stream;
+	ret_stream << ret_string;
+	boost::property_tree::ptree ret_tree;
+	boost::property_tree::read_json(ret_stream, ret_tree);
+	optional<string> err_string = ret_tree.get_optional<string>(ret_json_key__any__err_msg());
+	if (err_string != none) {
+		BOOST_REQUIRE_MESSAGE(false, *err_string);
+	}
+	optional<string> str = ret_tree.get_optional<string>(ret_json_key__generic_retVal());
+	BOOST_REQUIRE(str != none);
+	BOOST_REQUIRE((*str).size() > 0);
+	BOOST_REQUIRE(*str == "767a2b9b814b78d55e27ab7fc9bae03253a810c820e7abb4cabadde44b599d04");
+	cout << "bridged__derivation_to_scalar: " << *str << endl;
+}
+//
 BOOST_AUTO_TEST_CASE(bridged__decodeRct)
 {
 	using namespace serial_bridge;