Change credential challenge to possession

Change-Id: Ib36ef7bfe8d879e0ae117f79a1aab52062184e68
diff --git a/src/challenge/challenge-possession.hpp b/src/challenge/challenge-possession.hpp
new file mode 100644
index 0000000..165e20e
--- /dev/null
+++ b/src/challenge/challenge-possession.hpp
@@ -0,0 +1,89 @@
+/**
+ * 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_POSSESSION_HPP
+#define NDNCERT_CHALLENGE_POSSESSION_HPP
+
+#include "challenge-module.hpp"
+
+namespace ndn {
+namespace ndncert {
+
+/**
+ * @brief Provide Possession based challenge
+ *
+ * Possession here means possession of the certificate issued by a trust anchor. Once the requester
+ * could proof his/her possession of an existing certificate from this or other certificate issuer,
+ * the requester could finish the challenge.
+ *
+ * The requester needs to provide the proof of the possession of a certificate issued by
+ * a trust anchor. The challenge require the requester to pass the BASE64 certificate and
+ * 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. Requester provides a certificate signed by that trusted certificate as credential.
+ *   2. The challenge module will verify the signature of the credential.
+ *   3. The challenge module will Provide a 16 octet random number data.
+ *   3. The Requester signs the signed Data to prove it possess the private key
+ *
+ * Failure info when application fails:
+ *   INVALID_PARAMETER: When the cert issued from trust anchor or self-signed cert
+ *     cannot be validated.
+ *   FAILURE_INVALID_FORMAT: When the credential format is wrong.
+ */
+class ChallengePossession : public ChallengeModule
+{
+public:
+  ChallengePossession(const std::string& configPath = "");
+
+  // For CA
+  std::tuple<ErrorCode, std::string>
+  handleChallengeRequest(const Block& params, ca::RequestState& request) override;
+
+  // For Client
+  std::multimap<std::string, std::string>
+  getRequestedParameterList(Status status, const std::string& challengeStatus) override;
+
+  Block
+  genChallengeRequestTLV(Status status, const std::string& challengeStatus,
+                         const std::multimap<std::string, std::string>& params) override;
+
+  static void
+  fulfillParameters(std::multimap<std::string, std::string>& params,
+                    KeyChain& keyChain, const Name& issuedCertName, const std::array<uint8_t, 16>& nonce);
+
+  // challenge parameters
+  static const std::string PARAMETER_KEY_CREDENTIAL_CERT;
+  static const std::string PARAMETER_KEY_NONCE;
+  static const std::string PARAMETER_KEY_PROOF;
+  static const std::string NEED_PROOF;
+
+NDNCERT_PUBLIC_WITH_TESTS_ELSE_PRIVATE:
+  void
+  parseConfigFile();
+
+NDNCERT_PUBLIC_WITH_TESTS_ELSE_PRIVATE:
+  std::list<security::Certificate> m_trustAnchors;
+  std::string m_configFile;
+};
+
+} // namespace ndncert
+} // namespace ndn
+
+#endif // NDNCERT_CHALLENGE_POSSESSION_HPP