diff --git a/src/crypto-support/enc-tlv.hpp b/src/crypto-support/enc-tlv.hpp
new file mode 100644
index 0000000..07f17a5
--- /dev/null
+++ b/src/crypto-support/enc-tlv.hpp
@@ -0,0 +1,44 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2017-2019, Regents of the University of California.
+ *
+ * This file is part of ndncert, a certificate management system based on NDN.
+ *
+ * ndncert is free software: you can redistribute it and/or modify it under the terms
+ * of the GNU General Public License as published by the Free Software Foundation, either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * ndncert is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received copies of the GNU General Public License along with
+ * ndncert, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * See AUTHORS.md for complete list of ndncert authors and contributors.
+ */
+
+#ifndef NDNCERT_CRYPTO_SUPPORT_ENC_TLV_HPP
+#define NDNCERT_CRYPTO_SUPPORT_ENC_TLV_HPP
+
+#include <ndn-cxx/encoding/block-helpers.hpp>
+
+namespace ndn {
+namespace ndncert {
+
+enum {
+  ENCRYPTED_PAYLOAD = 630,
+  INITIAL_VECTOR = 632,
+};
+
+Block
+genEncBlock(uint32_t tlv_type, const uint8_t* key, size_t keyLen, const uint8_t* payload, size_t payloadSize);
+
+Buffer
+parseEncBlock(const uint8_t* key, size_t keyLen, const Block& block);
+
+
+} // namespace ndncert
+} // namespace ndn
+
+#endif // NDNCERT_CRYPTO_SUPPORT_ENC_TLV_HPP