diff --git a/tests/key-chain-fixture.cpp b/tests/key-chain-fixture.cpp
new file mode 100644
index 0000000..29a75b8
--- /dev/null
+++ b/tests/key-chain-fixture.cpp
@@ -0,0 +1,119 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2014-2020, Regents of the University of California
+ *
+ * NAC 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.
+ *
+ * NAC 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 NAC library authors and contributors.
+ */
+
+#include "tests/key-chain-fixture.hpp"
+
+#include <ndn-cxx/util/io.hpp>
+
+#include <boost/filesystem.hpp>
+
+namespace ndn {
+namespace nac {
+namespace tests {
+
+using namespace ndn::security;
+
+KeyChainFixture::KeyChainFixture()
+  : m_keyChain("pib-memory:", "tpm-memory:")
+{
+}
+
+KeyChainFixture::~KeyChainFixture()
+{
+  boost::system::error_code ec;
+  for (const auto& certFile : m_certFiles) {
+    boost::filesystem::remove(certFile, ec); // ignore error
+  }
+}
+
+Certificate
+KeyChainFixture::makeCert(const Key& key, const std::string& issuer, const Key& signingKey)
+{
+  Certificate cert;
+  cert.setName(Name(key.getName())
+               .append(issuer)
+               .appendVersion());
+
+  // set metainfo
+  cert.setContentType(tlv::ContentType_Key);
+  cert.setFreshnessPeriod(1_h);
+
+  // set content
+  cert.setContent(key.getPublicKey().data(), key.getPublicKey().size());
+
+  // set signature info
+  ndn::SignatureInfo info;
+  auto now = time::system_clock::now();
+  info.setValidityPeriod(ValidityPeriod(now - 30_days, now + 30_days));
+
+  m_keyChain.sign(cert, signingByKey(signingKey ? signingKey : key).setSignatureInfo(info));
+  return cert;
+}
+
+bool
+KeyChainFixture::saveCert(const Data& cert, const std::string& filename)
+{
+  m_certFiles.push_back(filename);
+  try {
+    ndn::io::save(cert, filename);
+    return true;
+  }
+  catch (const ndn::io::Error&) {
+    return false;
+  }
+}
+
+bool
+KeyChainFixture::saveIdentityCert(const Identity& identity, const std::string& filename)
+{
+  Certificate cert;
+  try {
+    cert = identity.getDefaultKey().getDefaultCertificate();
+  }
+  catch (const Pib::Error&) {
+    return false;
+  }
+
+  return saveCert(cert, filename);
+}
+
+bool
+KeyChainFixture::saveIdentityCert(const Name& identityName, const std::string& filename,
+                                  bool allowCreate)
+{
+  Identity id;
+  try {
+    id = m_keyChain.getPib().getIdentity(identityName);
+  }
+  catch (const Pib::Error&) {
+    if (allowCreate) {
+      id = m_keyChain.createIdentity(identityName);
+    }
+  }
+
+  if (!id) {
+    return false;
+  }
+
+  return saveIdentityCert(id, filename);
+}
+
+} // namespace tests
+} // namespace nac
+} // namespace ndn