Add proof of private key challenge

Change-Id: Ic48b65c550603656c962e3c251f4dac1759cb4a1
diff --git a/src/challenge-module/challenge-private-key.hpp b/src/challenge-module/challenge-private-key.hpp
new file mode 100644
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--- /dev/null
+++ b/src/challenge-module/challenge-private-key.hpp
@@ -0,0 +1,75 @@
+/**
+ * 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_CHALLENGE_PRIVATE_KEY_HPP
+#define NDNCERT_CHALLENGE_PRIVATE_KEY_HPP
+
+#include "../challenge-module.hpp"
+
+namespace ndn {
+namespace ndncert {
+
+/**
+ * @brief Private Key based challenge (for renewal and revocation)
+ *
+ * Once the requester could proof his/her possession of the private key corresponds to
+ * the current CA's previous issued certificate, the requester could finish the challenge.
+ *
+ * The requester needs to provide the proof of the possession the private for the certificate
+ * for the previous cerificate. The challenge require the requester to a BASE64 Data packet
+ * signed by the credential pub key and whose content is the request id.
+ *
+ * The main process of this challenge module is:
+ *   1. The requester sign a Data packet which content is the request id.
+ *   2. The challenge module will verify the signature of the credential.
+ *
+ * Failure info when application fails:
+ *   FAILURE_INVALID_CREDENTIAL: When the signature cannot be validated.
+ *   FAILURE_INVALID_FORMAT: When the credential format is wrong.
+ */
+class ChallengePrivateKey : public ChallengeModule
+{
+public:
+  ChallengePrivateKey();
+
+  // For CA
+  void
+  handleChallengeRequest(const Block& params, CertificateRequest& request) override;
+
+  // For Client
+  JsonSection
+  getRequirementForChallenge(int status, const std::string& challengeStatus) override;
+
+  JsonSection
+  genChallengeRequestJson(int status, const std::string& challengeStatus, const JsonSection& params) override;
+
+  Block
+  genChallengeRequestTLV(int status, const std::string& challengeStatus, const JsonSection& params) override;
+
+PUBLIC_WITH_TESTS_ELSE_PRIVATE:
+  static const std::string FAILURE_INVALID_REQUEST_TYPE;
+  static const std::string FAILURE_INVALID_CREDENTIAL;
+  static const std::string FAILURE_INVALID_FORMAT_SELF_SIGNED;
+  static const std::string JSON_PROOF_OF_PRIVATE_KEY;
+};
+
+} // namespace ndncert
+} // namespace ndn
+
+#endif // NDNCERT_CHALLENGE_PRIVATE_KEY_HPP