diff --git a/src/security/v2/validation-policy-command-interest.cpp b/src/security/v2/validation-policy-command-interest.cpp
new file mode 100644
index 0000000..5753ef3
--- /dev/null
+++ b/src/security/v2/validation-policy-command-interest.cpp
@@ -0,0 +1,173 @@
+/* -*- 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 "validation-policy-command-interest.hpp"
+#include "../pib/key.hpp"
+
+namespace ndn {
+namespace security {
+namespace v2 {
+
+ValidationPolicyCommandInterest::ValidationPolicyCommandInterest(unique_ptr<ValidationPolicy> inner,
+                                                                 const Options& options)
+  : m_options(options)
+  , m_index(m_container.get<0>())
+  , m_queue(m_container.get<1>())
+{
+  if (inner == nullptr) {
+    BOOST_THROW_EXCEPTION(std::invalid_argument("inner policy is missing"));
+  }
+  setInnerPolicy(std::move(inner));
+
+  m_options.gracePeriod = std::max(m_options.gracePeriod, time::nanoseconds::zero());
+}
+
+void
+ValidationPolicyCommandInterest::checkPolicy(const Data& data, const shared_ptr<ValidationState>& state,
+                                             const ValidationContinuation& continueValidation)
+{
+  getInnerPolicy().checkPolicy(data, state, continueValidation);
+}
+
+void
+ValidationPolicyCommandInterest::checkPolicy(const Interest& interest, const shared_ptr<ValidationState>& state,
+                                             const ValidationContinuation& continueValidation)
+{
+  bool isOk = false;
+  Name keyName;
+  uint64_t timestamp = 0;
+  std::tie(isOk, keyName, timestamp) = parseCommandInterest(interest, state);
+  if (!isOk) {
+    return;
+  }
+
+  if (!checkTimestamp(state, keyName, timestamp)) {
+    return;
+  }
+  getInnerPolicy().checkPolicy(interest, state, std::bind(continueValidation, _1, _2));
+}
+
+void
+ValidationPolicyCommandInterest::cleanup()
+{
+  time::steady_clock::TimePoint expiring = time::steady_clock::now() - m_options.recordLifetime;
+
+  while ((!m_queue.empty() && m_queue.front().lastRefreshed <= expiring) ||
+         (m_options.maxRecords >= 0 &&
+          m_queue.size() > static_cast<size_t>(m_options.maxRecords))) {
+    m_queue.pop_front();
+  }
+}
+
+std::tuple<bool, Name, uint64_t>
+ValidationPolicyCommandInterest::parseCommandInterest(const Interest& interest,
+                                                      const shared_ptr<ValidationState>& state) const
+{
+  const Name& name = interest.getName();
+  if (name.size() < command_interest::MIN_SIZE) {
+    state->fail({ValidationError::POLICY_ERROR, "Command interest name `" +
+                 interest.getName().toUri() + "` is too short"});
+    return std::make_tuple(false, Name(), 0);
+  }
+
+  const name::Component& timestampComp = name.at(command_interest::POS_TIMESTAMP);
+  if (!timestampComp.isNumber()) {
+    state->fail({ValidationError::POLICY_ERROR, "Command interest `" +
+                 interest.getName().toUri() + "` doesn't include timestamp component"});
+    return std::make_tuple(false, Name(), 0);
+  }
+
+  SignatureInfo sig;
+  try {
+    sig.wireDecode(name[signed_interest::POS_SIG_INFO].blockFromValue());
+  }
+  catch (const tlv::Error&) {
+    state->fail({ValidationError::POLICY_ERROR, "Command interest `" +
+                 interest.getName().toUri() + "` does not include SignatureInfo component"});
+    return std::make_tuple(false, Name(), 0);
+  }
+
+  if (!sig.hasKeyLocator()) {
+    state->fail({ValidationError::INVALID_KEY_LOCATOR, "Command interest `" +
+                 interest.getName().toUri() + "` does not include KeyLocator"});
+    return std::make_tuple(false, Name(), 0);
+  }
+
+  const KeyLocator& keyLocator = sig.getKeyLocator();
+  if (keyLocator.getType() != KeyLocator::KeyLocator_Name) {
+    state->fail({ValidationError::INVALID_KEY_LOCATOR, "Command interest `" +
+                 interest.getName().toUri() + "` KeyLocator type is not Name"});
+    return std::make_tuple(false, Name(), 0);
+  }
+
+  return std::make_tuple(true, keyLocator.getName(), timestampComp.toNumber());
+}
+
+bool
+ValidationPolicyCommandInterest::checkTimestamp(const shared_ptr<ValidationState>& state,
+                                                const Name& keyName, uint64_t timestamp)
+{
+  this->cleanup();
+
+  time::system_clock::TimePoint now = time::system_clock::now();
+  time::system_clock::TimePoint timestampPoint = time::fromUnixTimestamp(time::milliseconds(timestamp));
+  if (timestampPoint < now - m_options.gracePeriod || timestampPoint > now + m_options.gracePeriod) {
+    state->fail({ValidationError::POLICY_ERROR, "Timestamp is outside the grace period for key " + keyName.toUri()});
+    return false;
+  }
+  auto it = m_index.find(keyName);
+  if (it != m_index.end()) {
+    if (timestamp <= it->timestamp) {
+      state->fail({ValidationError::POLICY_ERROR, "Timestamp is reordered for key " + keyName.toUri()});
+      return false;
+    }
+  }
+
+  shared_ptr<InterestValidationState> interestState = std::dynamic_pointer_cast<InterestValidationState>(state);
+  interestState->afterSuccess.connect(bind(&ValidationPolicyCommandInterest::insertNewRecord,
+                                           this, _1, keyName, timestamp));
+  return true;
+}
+
+void
+ValidationPolicyCommandInterest::insertNewRecord(const Interest& interest, const Name& keyName,
+                                                 uint64_t timestamp)
+{
+  // try to insert new record
+  time::steady_clock::TimePoint now = time::steady_clock::now();
+  Queue::iterator i = m_queue.end();
+  bool isNew = false;
+  LastTimestampRecord newRecord{keyName, timestamp, now};
+  std::tie(i, isNew) = m_queue.push_back(newRecord);
+
+  if (!isNew) {
+    BOOST_ASSERT(i->keyName == keyName);
+
+    // set lastRefreshed field, and move to queue tail
+    m_queue.erase(i);
+    isNew = m_queue.push_back(newRecord).second;
+    BOOST_VERIFY(isNew);
+  }
+}
+
+} // namespace v2
+} // namespace security
+} // namespace ndn
diff --git a/src/security/v2/validation-policy-command-interest.hpp b/src/security/v2/validation-policy-command-interest.hpp
new file mode 100644
index 0000000..96a9012
--- /dev/null
+++ b/src/security/v2/validation-policy-command-interest.hpp
@@ -0,0 +1,161 @@
+/* -*- 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.
+ */
+
+#ifndef NDN_SECURITY_V2_VALIDATION_POLICY_COMMAND_INTEREST_HPP
+#define NDN_SECURITY_V2_VALIDATION_POLICY_COMMAND_INTEREST_HPP
+
+#include "validation-policy.hpp"
+#include <boost/multi_index_container.hpp>
+#include <boost/multi_index/ordered_index.hpp>
+#include <boost/multi_index/sequenced_index.hpp>
+#include <boost/multi_index/key_extractors.hpp>
+
+namespace ndn {
+namespace security {
+namespace v2 {
+
+/** \brief Validation policy for stop-and-wait command Interests
+ *  \sa https://redmine.named-data.net/projects/ndn-cxx/wiki/CommandInterest
+ *
+ *  This policy checks the timestamp field of a stop-and-wait command Interest.
+ *  Signed Interest validation and Data validation requests are delegated to an inner policy.
+ */
+class ValidationPolicyCommandInterest : public ValidationPolicy
+{
+public:
+  class Options
+  {
+  public:
+    Options()
+    {
+    }
+
+  public:
+    /** \brief tolerance of initial timestamp
+     *
+     *  A stop-and-wait command Interest is considered "initial" if the validator
+     *  has not recorded the last timestamp from the same public key, or when
+     *  such knowledge has been erased.
+     *  For an initial command Interest, its timestamp is compared to the current
+     *  system clock, and the command Interest is rejected if the absolute difference
+     *  is greater than the grace interval.
+     *
+     *  This should be positive.
+     *  Setting this option to 0 or negative causes the validator to require exactly same
+     *  timestamp as the system clock, which most likely rejects all command Interests.
+     */
+    time::nanoseconds gracePeriod = time::seconds(120);
+
+    /** \brief max number of distinct public keys of which to record the last timestamp
+     *
+     *  The validator records last timestamps for every public key.
+     *  For a subsequent command Interest using the same public key,
+     *  its timestamp is compared to the last timestamp from that public key,
+     *  and the command Interest is rejected if its timestamp is
+     *  less than or equal to the recorded timestamp.
+     *
+     *  This option limits the number of distinct public keys being tracked.
+     *  If the limit is exceeded, the oldest record is deleted.
+     *
+     *  Setting this option to -1 allows tracking unlimited public keys.
+     *  Setting this option to 0 disables last timestamp records and causes
+     *  every command Interest to be processed as initial.
+     */
+    ssize_t maxRecords = 1000;
+
+    /** \brief max lifetime of a last timestamp record
+     *
+     *  A last timestamp record expires and can be deleted if it has not been refreshed
+     *  within this duration.
+     *  Setting this option to 0 or negative makes last timestamp records expire immediately
+     *  and causes every command Interest to be processed as initial.
+     */
+    time::nanoseconds recordLifetime = time::hours(1);
+  };
+
+  /** \brief constructor
+   *  \param inner a Validator for signed Interest signature validation and Data validation;
+   *               this must not be nullptr
+   *  \param options stop-and-wait command Interest validation options
+   *  \throw std::invalid_argument inner policy is nullptr
+   */
+  explicit
+  ValidationPolicyCommandInterest(unique_ptr<ValidationPolicy> inner,
+                                  const Options& options = {});
+
+protected:
+  void
+  checkPolicy(const Data& data, const shared_ptr<ValidationState>& state,
+              const ValidationContinuation& continueValidation) override;
+
+  void
+  checkPolicy(const Interest& interest, const shared_ptr<ValidationState>& state,
+              const ValidationContinuation& continueValidation) override;
+
+private:
+  void
+  cleanup();
+
+  std::tuple<bool, Name, uint64_t>
+  parseCommandInterest(const Interest& interest, const shared_ptr<ValidationState>& state) const;
+
+  bool
+  checkTimestamp(const shared_ptr<ValidationState>& state,
+                 const Name& keyName, uint64_t timestamp);
+
+  void
+  insertNewRecord(const Interest& interest, const Name& keyName,
+                  uint64_t timestamp);
+
+private:
+  unique_ptr<ValidationPolicy> m_innerPolicy;
+  Options m_options;
+
+  struct LastTimestampRecord
+  {
+    Name keyName;
+    uint64_t timestamp;
+    time::steady_clock::TimePoint lastRefreshed;
+  };
+
+  typedef boost::multi_index_container<
+    LastTimestampRecord,
+    boost::multi_index::indexed_by<
+      boost::multi_index::ordered_unique<
+        boost::multi_index::member<LastTimestampRecord, Name, &LastTimestampRecord::keyName>
+      >,
+      boost::multi_index::sequenced<>
+    >
+  > Container;
+  typedef Container::nth_index<0>::type Index;
+  typedef Container::nth_index<1>::type Queue;
+
+  Container m_container;
+  Index& m_index;
+  Queue& m_queue;
+};
+
+} // namespace v2
+} // namespace security
+} // namespace ndn
+
+
+#endif // NDN_SECURITY_V2_VALIDATION_POLICY_COMMAND_INTEREST_HPP
diff --git a/src/security/v2/validation-state.cpp b/src/security/v2/validation-state.cpp
index 269ef2d..4267c7f 100644
--- a/src/security/v2/validation-state.cpp
+++ b/src/security/v2/validation-state.cpp
@@ -149,10 +149,10 @@
                                                  const InterestValidationSuccessCallback& successCb,
                                                  const InterestValidationFailureCallback& failureCb)
   : m_interest(interest)
-  , m_successCb(successCb)
   , m_failureCb(failureCb)
 {
-  BOOST_ASSERT(m_successCb != nullptr);
+  afterSuccess.connect(successCb);
+  BOOST_ASSERT(successCb != nullptr);
   BOOST_ASSERT(m_failureCb != nullptr);
 }
 
@@ -169,7 +169,7 @@
 {
   if (verifySignature(m_interest, trustedCert)) {
     NDN_LOG_TRACE_DEPTH("OK signature for interest `" << m_interest.getName() << "`");
-    m_successCb(m_interest);
+    this->afterSuccess(m_interest);
     BOOST_ASSERT(!m_hasOutcome);
     m_hasOutcome = true;
   }
@@ -183,7 +183,7 @@
 InterestValidationState::bypassValidation()
 {
   NDN_LOG_TRACE_DEPTH("Signature verification bypassed for interest `" << m_interest.getName() << "`");
-  m_successCb(m_interest);
+  this->afterSuccess(m_interest);
   BOOST_ASSERT(!m_hasOutcome);
   m_hasOutcome = true;
 }
diff --git a/src/security/v2/validation-state.hpp b/src/security/v2/validation-state.hpp
index 2181fae..821b85c 100644
--- a/src/security/v2/validation-state.hpp
+++ b/src/security/v2/validation-state.hpp
@@ -25,6 +25,7 @@
 #include "../../tag-host.hpp"
 #include "validation-callback.hpp"
 #include "certificate.hpp"
+#include "../../util/signal.hpp"
 
 #include <unordered_set>
 #include <list>
@@ -223,6 +224,9 @@
   const Interest&
   getOriginalInterest() const;
 
+public:
+  util::Signal<InterestValidationState, Interest> afterSuccess;
+
 private:
   void
   verifyOriginalPacket(const Certificate& trustedCert) final;