diff --git a/src/security/pib/detail/identity-impl.cpp b/src/security/pib/detail/identity-impl.cpp
new file mode 100644
index 0000000..af01dc5
--- /dev/null
+++ b/src/security/pib/detail/identity-impl.cpp
@@ -0,0 +1,122 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2013-2017 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.
+ */
+
+#include "identity-impl.hpp"
+#include "../pib-impl.hpp"
+#include "../pib.hpp"
+
+namespace ndn {
+namespace security {
+namespace pib {
+namespace detail {
+
+IdentityImpl::IdentityImpl(const Name& identityName, shared_ptr<PibImpl> impl, bool needInit)
+  : m_name(identityName)
+  , m_isDefaultKeyLoaded(false)
+  , m_keys(identityName, impl)
+  , m_impl(impl)
+{
+  BOOST_ASSERT(impl != nullptr);
+
+  if (needInit) {
+    m_impl->addIdentity(m_name);
+  }
+  else if (!m_impl->hasIdentity(m_name)) {
+    BOOST_THROW_EXCEPTION(Pib::Error("Identity " + m_name.toUri() + " does not exist"));
+  }
+}
+
+Key
+IdentityImpl::addKey(const uint8_t* key, size_t keyLen, const Name& keyName)
+{
+  BOOST_ASSERT(m_keys.isConsistent());
+
+  if (m_keys.find(keyName) != m_keys.end()) {
+    BOOST_THROW_EXCEPTION(Pib::Error("Cannot overwrite existing key " + keyName.toUri()));
+  }
+
+  return m_keys.add(key, keyLen, keyName);
+}
+
+void
+IdentityImpl::removeKey(const Name& keyName)
+{
+  BOOST_ASSERT(m_keys.isConsistent());
+
+  if (m_isDefaultKeyLoaded && m_defaultKey.getName() == keyName)
+    m_isDefaultKeyLoaded = false;
+
+  m_keys.remove(keyName);
+}
+
+Key
+IdentityImpl::getKey(const Name& keyName) const
+{
+  BOOST_ASSERT(m_keys.isConsistent());
+
+  return m_keys.get(keyName);
+}
+
+const KeyContainer&
+IdentityImpl::getKeys() const
+{
+  BOOST_ASSERT(m_keys.isConsistent());
+
+  return m_keys;
+}
+
+const Key&
+IdentityImpl::setDefaultKey(const Name& keyName)
+{
+  BOOST_ASSERT(m_keys.isConsistent());
+
+  m_defaultKey = m_keys.get(keyName);
+  m_isDefaultKeyLoaded = true;
+  m_impl->setDefaultKeyOfIdentity(m_name, keyName);
+  return m_defaultKey;
+}
+
+const Key&
+IdentityImpl::setDefaultKey(const uint8_t* key, size_t keyLen, const Name& keyName)
+{
+  addKey(key, keyLen, keyName);
+  return setDefaultKey(keyName);
+}
+
+const Key&
+IdentityImpl::getDefaultKey() const
+{
+  BOOST_ASSERT(m_keys.isConsistent());
+
+  if (!m_isDefaultKeyLoaded) {
+    m_defaultKey = m_keys.get(m_impl->getDefaultKeyOfIdentity(m_name));
+    m_isDefaultKeyLoaded = true;
+  }
+
+  BOOST_ASSERT(m_impl->getDefaultKeyOfIdentity(m_name) == m_defaultKey.getName());
+
+  return m_defaultKey;
+}
+
+} // namespace detail
+} // namespace pib
+} // namespace security
+} // namespace ndn