diff --git a/src/crypto-support/crypto-helper.hpp b/src/crypto-support/crypto-helper.hpp
new file mode 100644
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+++ b/src/crypto-support/crypto-helper.hpp
@@ -0,0 +1,90 @@
+/* -*- 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_CRYPTO_HELPER_HPP
+#define NDNCERT_CRYPTO_SUPPORT_CRYPTO_HELPER_HPP
+
+#include "certificate-request.hpp"
+#include <openssl/evp.h>
+#include <openssl/ec.h>
+
+static const int INFO_LEN = 10;
+static const uint8_t INFO[] = {0xf0,0xf1,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7,0xf8,0xf9};
+
+namespace ndn {
+namespace ndncert {
+
+struct ECDH_CTX{
+  int EC_NID;
+  EVP_PKEY_CTX *ctx_params;
+  EVP_PKEY_CTX *ctx_keygen;
+  EVP_PKEY *privkey;
+  EVP_PKEY *peerkey;
+  EVP_PKEY *params;
+  uint8_t publicKey[256];
+  int publicKeyLen;
+  uint8_t sharedSecret[256];
+  int sharedSecretLen;
+};
+
+class ECDHState
+{
+public:
+  ECDHState();
+  ~ECDHState();
+
+  std::string
+  getBase64PubKey();
+
+  uint8_t*
+  deriveSecret(const std::string& peerKeyStr);
+  //unique_ptr<ECDH_CTX_T> context;
+  unique_ptr<ECDH_CTX> context;
+
+PUBLIC_WITH_TESTS_ELSE_PRIVATE:
+  uint8_t*
+  deriveSecret(const uint8_t* peerkey, int peerKeySize);
+
+  uint8_t*
+  getRawSelfPubKey();
+};
+
+int
+hkdf(const uint8_t* secret, int secretLen, const uint8_t* salt,
+     int saltLen, uint8_t* okm, int okm_len,
+     const uint8_t* info=INFO, int info_len=INFO_LEN);
+
+int ndn_compute_hmac_sha256 (const uint8_t *data, const unsigned  data_length,
+                                    const uint8_t *key, const unsigned key_length,
+                                    uint8_t *prk);
+
+void
+handleErrors(const std::string& errorInfo);
+
+class CryptoError : public std::runtime_error
+{
+public:
+  using std::runtime_error::runtime_error;
+};
+
+} // namespace ndncert
+} // namespace ndn
+
+#endif // NDNCERT_CRYPTO_SUPPORT_CRYPTO_HELPER_HPP