diff --git a/src/security/identity.cpp b/src/security/identity.cpp
new file mode 100644
index 0000000..7662a0a
--- /dev/null
+++ b/src/security/identity.cpp
@@ -0,0 +1,164 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2013-2015 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.hpp"
+#include "pib-impl.hpp"
+#include "pib.hpp"
+
+namespace ndn {
+namespace security {
+
+const name::Component Identity::EMPTY_KEY_ID;
+
+Identity::Identity()
+  : m_hasDefaultKey(false)
+  , m_needRefreshKeys(false)
+  , m_impl(nullptr)
+{
+}
+
+Identity::Identity(const Name& identityName, shared_ptr<PibImpl> impl, bool needInit)
+  : m_name(identityName)
+  , m_hasDefaultKey(false)
+  , m_needRefreshKeys(true)
+  , m_impl(impl)
+{
+  validityCheck();
+
+  if (needInit)
+    m_impl->addIdentity(m_name);
+  else if (!m_impl->hasIdentity(m_name))
+    throw Pib::Error("Identity: " + m_name.toUri() + " does not exist");
+}
+
+const Name&
+Identity::getName() const
+{
+  validityCheck();
+
+  return m_name;
+}
+
+Key
+Identity::addKey(const PublicKey& publicKey, const name::Component& keyId)
+{
+  validityCheck();
+
+  name::Component actualKeyId = keyId;
+  if (actualKeyId == EMPTY_KEY_ID) {
+    const Block& digest = publicKey.computeDigest();
+    actualKeyId = name::Component(digest.wire(), digest.size());
+  }
+
+  if (!m_needRefreshKeys && m_keys.find(actualKeyId) == m_keys.end()) {
+    // if we have already loaded all the keys, but the new key is not one of them
+    // the KeyContainer should be refreshed
+    m_needRefreshKeys = true;
+  }
+
+  return Key(m_name, actualKeyId, publicKey, m_impl);
+}
+
+void
+Identity::removeKey(const name::Component& keyId)
+{
+  validityCheck();
+
+  if (m_hasDefaultKey && m_defaultKey.getKeyId() == keyId)
+    m_hasDefaultKey = false;
+
+  m_impl->removeKey(m_name, keyId);
+  m_needRefreshKeys = true;
+}
+
+Key
+Identity::getKey(const name::Component& keyId)
+{
+  validityCheck();
+
+  return Key(m_name, keyId, m_impl);
+}
+
+const KeyContainer&
+Identity::getKeys()
+{
+  validityCheck();
+
+  if (m_needRefreshKeys) {
+    m_keys = std::move(KeyContainer(m_name, m_impl->getKeysOfIdentity(m_name), m_impl));
+    m_needRefreshKeys = false;
+  }
+
+  return m_keys;
+}
+
+Key&
+Identity::setDefaultKey(const name::Component& keyId)
+{
+  validityCheck();
+
+  m_defaultKey = std::move(Key(m_name, keyId, m_impl));
+  m_hasDefaultKey = true;
+
+  m_impl->setDefaultKeyOfIdentity(m_name, keyId);
+  return m_defaultKey;
+}
+
+Key&
+Identity::setDefaultKey(const PublicKey& publicKey, const name::Component& keyId)
+{
+  const Key& keyEntry = addKey(publicKey, keyId);
+  return setDefaultKey(keyEntry.getKeyId());
+}
+
+Key&
+Identity::getDefaultKey()
+{
+  validityCheck();
+
+  if (!m_hasDefaultKey) {
+    m_defaultKey = std::move(Key(m_name, m_impl->getDefaultKeyOfIdentity(m_name), m_impl));
+    m_hasDefaultKey = true;
+  }
+
+  return m_defaultKey;
+}
+
+Identity::operator bool() const
+{
+  return !(this->operator!());
+}
+
+bool
+Identity::operator!() const
+{
+  return (m_impl == nullptr);
+}
+
+void
+Identity::validityCheck() const
+{
+  if (m_impl == nullptr)
+    throw std::domain_error("Invalid Identity instance");
+}
+
+} // namespace security
+} // namespace ndn