diff --git a/src/logic.cpp b/src/logic.cpp
index aa08acc..278115e 100644
--- a/src/logic.cpp
+++ b/src/logic.cpp
@@ -279,6 +279,7 @@
         insertToDiffLog(commit, previousRoot);
 
         satisfyPendingSyncInterests(prefix, commit);
+        formAndSendExcludeInterest(prefix, *commit, previousRoot);
       }
     }
   }
@@ -344,12 +345,23 @@
 Logic::onSyncData(const Interest& interest, Data& data)
 {
   _LOG_DEBUG_ID(">> Logic::onSyncData");
-  if (static_cast<bool>(m_validator))
-    m_validator->validate(data,
-                          bind(&Logic::onSyncDataValidated, this, _1),
-                          bind(&Logic::onSyncDataValidationFailed, this, _1));
-  else
+  // if (static_cast<bool>(m_validator))
+  //   m_validator->validate(data,
+  //                         bind(&Logic::onSyncDataValidated, this, _1),
+  //                         bind(&Logic::onSyncDataValidationFailed, this, _1));
+  // else
+  //   onSyncDataValidated(data.shared_from_this());
+
+  if (interest.getExclude().empty()) {
+    _LOG_DEBUG_ID("First data");
     onSyncDataValidated(data.shared_from_this());
+  }
+  else {
+    _LOG_DEBUG_ID("Data obtained using exclude filter");
+    onSyncDataValidated(data.shared_from_this(), false);
+  }
+  sendExcludeInterest(interest, data);
+
   _LOG_DEBUG_ID("<< Logic::onSyncData");
 }
 
@@ -375,12 +387,12 @@
 }
 
 void
-Logic::onSyncDataValidated(const shared_ptr<const Data>& data)
+Logic::onSyncDataValidated(const shared_ptr<const Data>& data, bool firstData)
 {
   Name name = data->getName();
   ConstBufferPtr digest = make_shared<ndn::Buffer>(name.get(-1).value(), name.get(-1).value_size());
 
-  processSyncData(name, digest, data->getContent().blockFromValue());
+  processSyncData(name, digest, data->getContent().blockFromValue(), firstData);
 }
 
 void
@@ -475,7 +487,8 @@
 void
 Logic::processSyncData(const Name& name,
                        ndn::ConstBufferPtr digest,
-                       const Block& syncReplyBlock)
+                       const Block& syncReplyBlock,
+                       bool firstData)
 {
   _LOG_DEBUG_ID(">> Logic::processSyncData");
   DiffStatePtr commit = make_shared<DiffState>();
@@ -525,7 +538,7 @@
     return;
   }
 
-  if (static_cast<bool>(commit) && !commit->getLeaves().empty()) {
+  if (static_cast<bool>(commit) && !commit->getLeaves().empty() && firstData) {
     // state changed and it is safe to express a new interest
     time::steady_clock::Duration after = time::milliseconds(m_reexpressionJitter());
     _LOG_DEBUG_ID("Reschedule sync interest after: " << after);
@@ -750,4 +763,49 @@
   _LOG_DEBUG_ID("<< Logic::onRecoveryTimeout");
 }
 
+void
+Logic::sendExcludeInterest(const Interest& interest, const Data& data)
+{
+  _LOG_DEBUG_ID(">> Logic::sendExcludeInterest");
+
+  Name interestName = interest.getName();
+  Interest excludeInterest(interestName);
+
+  Exclude exclude = interest.getExclude();
+  exclude.excludeOne(data.getFullName().get(-1));
+  excludeInterest.setExclude(exclude);
+
+  excludeInterest.setInterestLifetime(m_syncInterestLifetime);
+
+  m_face.expressInterest(excludeInterest, bind(&Logic::onSyncData, this, _1, _2),
+                                          bind(&Logic::onSyncTimeout, this, _1));
+
+  _LOG_DEBUG_ID("Send interest: " << excludeInterest.getName());
+  _LOG_DEBUG_ID("<< Logic::sendExcludeInterest");
+}
+
+void
+Logic::formAndSendExcludeInterest(const Name& nodePrefix, const State& commit, ndn::ConstBufferPtr previousRoot)
+{
+  _LOG_DEBUG_ID(">> Logic::formAndSendExcludeInterest");
+  Name interestName;
+  interestName.append(m_syncPrefix)
+              .append(ndn::name::Component(*previousRoot));
+  Interest interest(interestName);
+
+  shared_ptr<Data> data = make_shared<Data>(interestName);
+  data->setContent(commit.wireEncode());
+  data->setFreshnessPeriod(m_syncReplyFreshness);
+  if (m_nodeList.find(nodePrefix) == m_nodeList.end())
+    return;
+  if (m_nodeList[nodePrefix].signingId.empty())
+    m_keyChain.sign(*data);
+  else
+    m_keyChain.signByIdentity(*data, m_nodeList[nodePrefix].signingId);
+
+  sendExcludeInterest(interest, *data);
+
+  _LOG_DEBUG_ID("<< Logic::formAndSendExcludeInterest");
+}
+
 } // namespace chronosync
\ No newline at end of file
diff --git a/src/logic.hpp b/src/logic.hpp
index c684fa2..c452d20 100644
--- a/src/logic.hpp
+++ b/src/logic.hpp
@@ -303,9 +303,10 @@
    * This method simply passes the valid reply to processSyncData.
    *
    * @param data The valid Sync Reply.
+   * @param firstData Whether the data is new or that obtained using exclude filter
    */
   void
-  onSyncDataValidated(const shared_ptr<const Data>& data);
+  onSyncDataValidated(const shared_ptr<const Data>& data, bool firstData = true);
 
   /**
    * @brief Process normal Sync Interest
@@ -343,11 +344,13 @@
    * @param name           The data name of the Sync Reply.
    * @param digest         The digest in the data name.
    * @param syncReplyBlock The content of the Sync Reply.
+   * @param firstData      Whether the data is new or obtained using exclude filter
    */
   void
   processSyncData(const Name& name,
                   ndn::ConstBufferPtr digest,
-                  const Block& syncReplyBlock);
+                  const Block& syncReplyBlock,
+                  bool firstData);
 
   /**
    * @brief Insert state diff into log
@@ -432,6 +435,29 @@
   void
   onRecoveryTimeout(const Interest& interest);
 
+  /**
+   * @brief Helper method to send Exclude Interest
+   *
+   * @param interest    The interest whose exclude filter will be augmented
+   * @param data        The data whose implicit digest will be inserted into exclude filter
+   */
+  void
+  sendExcludeInterest(const Interest& interest, const Data& data);
+
+  /**
+   * @brief Helper method to form the exclude Interest and calls sendExcludeInterest
+   *
+   * @param interest       The interest whose exclude filter will be augmented
+   * @param nodePrefix     The prefix of the sender node
+   * @param commit         The commit whose contents will be used to obtain the implicit
+                           digest to be excluded
+   * @param previousRoot   The digest to be included in the interest
+   */
+  void
+  formAndSendExcludeInterest(const Name& nodePrefix,
+                             const State& commit,
+                             ndn::ConstBufferPtr previousRoot);
+
 public:
   static const ndn::Name DEFAULT_NAME;
   static const ndn::Name EMPTY_NAME;