1 files changed, 67 insertions, 0 deletions
diff --git a/private_join_and_compute/crypto/ec_point_util.cc b/private_join_and_compute/crypto/ec_point_util.cc
new file mode 100644
index 0000000..54bbfb9
--- /dev/null
+++ b/private_join_and_compute/crypto/ec_point_util.cc
@@ -0,0 +1,67 @@
+/*
+ * Copyright 2019 Google Inc.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "private_join_and_compute/crypto/ec_point_util.h"
+
+#include <memory>
+#include <string>
+
+#include "absl/strings/string_view.h"
+#include "private_join_and_compute/crypto/big_num.h"
+#include "private_join_and_compute/crypto/context.h"
+#include "private_join_and_compute/crypto/ec_commutative_cipher.h"
+#include "private_join_and_compute/crypto/ec_group.h"
+#include "private_join_and_compute/crypto/ec_point.h"
+#include "private_join_and_compute/util/status.inc"
+
+namespace private_join_and_compute {
+
+ECPointUtil::ECPointUtil(std::unique_ptr<Context> context, ECGroup group)
+    : context_(std::move(context)), group_(std::move(group)) {}
+
+StatusOr<std::unique_ptr<ECPointUtil>> ECPointUtil::Create(int curve_id) {
+  std::unique_ptr<Context> context(new Context());
+  ASSIGN_OR_RETURN(ECGroup group, ECGroup::Create(curve_id, context.get()));
+  return std::unique_ptr<ECPointUtil>(
+      new ECPointUtil(std::move(context), std::move(group)));
+}
+
+StatusOr<std::string> ECPointUtil::GetRandomCurvePoint() {
+  ASSIGN_OR_RETURN(ECPoint point, group_.GetRandomGenerator());
+  return point.ToBytesCompressed();
+}
+
+StatusOr<std::string> ECPointUtil::HashToCurve(
+    absl::string_view input, ECCommutativeCipher::HashType hash_type) {
+  if (hash_type == ECCommutativeCipher::HashType::SHA512) {
+    ASSIGN_OR_RETURN(ECPoint point,
+                     group_.GetPointByHashingToCurveSha512(input));
+    return point.ToBytesCompressed();
+  }
+
+  if (hash_type == ECCommutativeCipher::HashType::SHA256) {
+    ASSIGN_OR_RETURN(ECPoint point,
+                     group_.GetPointByHashingToCurveSha256(input));
+    return point.ToBytesCompressed();
+  }
+
+  return InvalidArgumentError("Invalid hash type.");
+}
+
+bool ECPointUtil::IsCurvePoint(absl::string_view input) {
+  return group_.CreateECPoint(input).ok();
+}
+
+}  // namespace private_join_and_compute