diff --git a/tools/ndnsec/dsk-gen.hpp b/tools/ndnsec/dsk-gen.hpp
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+++ b/tools/ndnsec/dsk-gen.hpp
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+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2013-2014 Regents of the University of California.
+ *
+ * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
+ *
+ * ndn-cxx library is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * ndn-cxx library 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 Lesser General Public License for more details.
+ *
+ * You should have received copies of the GNU General Public License and GNU Lesser
+ * General Public License along with ndn-cxx, e.g., in COPYING.md file.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
+ *
+ * @author Yingdi Yu <http://irl.cs.ucla.edu/~yingdi/>
+ */
+
+#ifndef NDN_TOOLS_NDNSEC_DSK_GEN_HPP
+#define NDN_TOOLS_NDNSEC_DSK_GEN_HPP
+
+#include "util.hpp"
+
+int
+ndnsec_dsk_gen(int argc, char** argv)
+{
+  using namespace ndn;
+  namespace po = boost::program_options;
+
+  std::string identityName;
+  char keyType = 'r';
+
+  po::options_description description("General Usage\n"
+                                      "  ndnsec dsk-gen [-h] [-t keyType] identity\n"
+                                      "General options");
+  description.add_options()
+    ("help,h", "produce help message")
+    ("identity,i", po::value<std::string>(&identityName),
+     "identity name, for example, /ndn/ucla.edu/alice")
+    ("type,t", po::value<char>(&keyType)->default_value('r'),
+     "optional, key type, r for RSA key (default), e for ECDSA key.")
+    // ("size,s", po::value<int>(&keySize)->default_value(2048),
+    //  "optional, key size, 2048 (default)")
+    ;
+
+  po::positional_options_description p;
+  p.add("identity", 1);
+
+  po::variables_map vm;
+  try {
+    po::store(po::command_line_parser(argc, argv).options(description).positional(p).run(), vm);
+    po::notify(vm);
+  }
+  catch (const std::exception& e) {
+    std::cerr << "ERROR: " << e.what() << std::endl;
+    std::cerr << description << std::endl;
+    return 1;
+  }
+
+  if (vm.count("help") != 0) {
+    std::cerr << description << std::endl;
+    return 0;
+  }
+
+  if (vm.count("identity") == 0) {
+    std::cerr << "identity must be specified" << std::endl;
+    std::cerr << description << std::endl;
+    return 1;
+  }
+
+  shared_ptr<IdentityCertificate> kskCert;
+  Name signingCertName;
+
+  KeyChain keyChain;
+
+  try {
+    Name defaultCertName = keyChain.getDefaultCertificateNameForIdentity(identityName);
+    bool isDefaultDsk = false;
+    std::string keyUsageTag = defaultCertName.get(-3).toUri().substr(0,4);
+    if (keyUsageTag == "ksk-")
+      isDefaultDsk = false;
+    else if (keyUsageTag == "dsk-")
+      isDefaultDsk = true;
+    else {
+      std::cerr << "ERROR: Unknown key usage tag: " << keyUsageTag << std::endl;
+      return 1;
+    }
+
+    if (isDefaultDsk) {
+      shared_ptr<IdentityCertificate> dskCert = keyChain.getCertificate(defaultCertName);
+
+      if (static_cast<bool>(dskCert)) {
+        SignatureSha256WithRsa sha256sig(dskCert->getSignature());
+
+        Name keyLocatorName = sha256sig.getKeyLocator().getName();
+
+        Name kskName = IdentityCertificate::certificateNameToPublicKeyName(keyLocatorName);
+        Name kskCertName = keyChain.getDefaultCertificateNameForKey(kskName);
+        signingCertName = kskCertName;
+        kskCert = keyChain.getCertificate(kskCertName);
+      }
+      else {
+        std::cerr << "ERROR: The default certificate is missing." << std::endl;
+        return 1;
+      }
+    }
+    else {
+      signingCertName = defaultCertName;
+      kskCert = keyChain.getCertificate(defaultCertName);
+    }
+
+    if (!static_cast<bool>(kskCert)) {
+      std::cerr << "ERROR: KSK certificate is missing." << std::endl;
+      return 1;
+    }
+
+    Name newKeyName;
+    switch (keyType) {
+    case 'r':
+      {
+        RsaKeyParams params;
+        newKeyName = keyChain.generateRsaKeyPair(Name(identityName), false, params.getKeySize());
+        if (0 == newKeyName.size()) {
+          std::cerr << "ERROR: Fail to generate RSA key!" << std::endl;
+          return 1;
+        }
+        break;
+      }
+    case 'e':
+      {
+        EcdsaKeyParams params;
+        newKeyName = keyChain.generateEcdsaKeyPair(Name(identityName), false, params.getKeySize());
+        if (0 == newKeyName.size()) {
+          std::cerr << "ERROR: Fail to generate ECDSA key!" << std::endl;
+          return 1;
+        }
+        break;
+      }
+    default:
+      std::cerr << "ERROR: Unrecongized key type" << "\n";
+      std::cerr << description << std::endl;
+      return 1;
+    }
+
+    Name certName = newKeyName.getPrefix(-1);
+    certName.append("KEY")
+      .append(newKeyName.get(-1))
+      .append("ID-CERT")
+      .appendVersion();
+
+    shared_ptr<IdentityCertificate> certificate =
+      keyChain.prepareUnsignedIdentityCertificate(newKeyName,
+                                                  Name(identityName),
+                                                  kskCert->getNotBefore(),
+                                                  kskCert->getNotAfter(),
+                                                  kskCert->getSubjectDescriptionList());
+
+    if (static_cast<bool>(certificate))
+      certificate->encode();
+    else {
+      std::cerr << "ERROR: Cannot format the certificate of the requested dsk." << "\n";
+      return 1;
+    }
+
+    keyChain.sign(*certificate, signingCertName);
+
+    keyChain.addCertificateAsIdentityDefault(*certificate);
+
+    std::cerr << "OK: dsk certificate with name [" << certificate->getName() <<
+      "] has been successfully installed\n";
+    return 0;
+  }
+  catch (std::runtime_error& e) {
+    std::cerr << "ERROR: other runtime errors: " << e.what() << "\n";
+    return 1;
+  }
+}
+
+#endif // NDN_TOOLS_NDNSEC_DSK_GEN_HPP