--- /dev/null
+////////////////////////////////////////////////////////////////////////////
+//
+// Copyright 2016 Realm 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
+//
+// http://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.
+//
+////////////////////////////////////////////////////////////////////////////
+
+#ifndef REALM_OS_KEYCHAIN_HELPER_HPP
+#define REALM_OS_KEYCHAIN_HELPER_HPP
+
+#include <cstdint>
+#include <stdexcept>
+#include <vector>
+
+namespace realm {
+namespace keychain {
+
+std::vector<char> metadata_realm_encryption_key(bool check_legacy_service);
+
+class KeychainAccessException : public std::runtime_error {
+public:
+ KeychainAccessException(int32_t error_code);
+};
+
+}
+}
+
+#endif // REALM_OS_KEYCHAIN_HELPER_HPP