diff --git a/src/requester-state.hpp b/src/requester-state.hpp
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+++ b/src/requester-state.hpp
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+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2017-2020, 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_REQUESTER_STATE_HPP
+#define NDNCERT_REQUESTER_STATE_HPP
+
+#include "ndncert-common.hpp"
+#include "crypto-support/crypto-helper.hpp"
+#include "configuration.hpp"
+
+namespace ndn {
+namespace ndncert {
+
+struct RequesterState {
+  explicit
+  RequesterState(security::KeyChain& keyChain, const CaProfile& caItem, RequestType requestType);
+
+  /**
+   * The CA profile for this request.
+   */
+  CaProfile m_caItem;
+  /**
+   * The local keychain to generate and install identities, keys and certificates
+   */
+  security::KeyChain& m_keyChain;
+  /**
+   * The type of request. Either NEW, RENEW, or REVOKE.
+   */
+  RequestType m_type;
+
+  /**
+   * The identity name for the requesting certificate.
+   */
+  Name m_identityName;
+  /**
+   * The keypair for the request.
+   */
+  security::Key m_keyPair;
+  /**
+   * The CA-generated request ID for the request.
+   */
+  std::string m_requestId;
+  /**
+   * The current status of the request.
+   */
+  Status m_status = Status::NOT_STARTED;
+
+  /**
+   * The type of challenge chosen.
+   */
+  std::string m_challengeType;
+  /**
+   * The status of the current challenge.
+   */
+  std::string m_challengeStatus;
+  /**
+   * The remaining number of tries left for the challenge
+   */
+  int m_remainingTries = 0;
+  /**
+   * The time this challenge will remain fresh
+   */
+  time::system_clock::TimePoint m_freshBefore;
+  /**
+   * the name of the certificate being issued.
+   */
+  Name m_issuedCertName;
+  /**
+   * ecdh state.
+   */
+  ECDHState m_ecdh;
+  /**
+   * AES key derived from the ecdh shared secret.
+   */
+  uint8_t m_aesKey[16] = {0};
+  /**
+   * State about how identity/key is generated.
+   */
+  bool m_isNewlyCreatedIdentity = false;
+  bool m_isNewlyCreatedKey = false;
+};
+
+}  // namespace ndncert
+}  // namespace ndn
+
+#endif  // NDNCERT_REQUESTER_STATE_HPP