diff --git a/src/clients/iterative-query-controller.cpp b/src/clients/iterative-query-controller.cpp
index 5a143a5..54bbb9a 100644
--- a/src/clients/iterative-query-controller.cpp
+++ b/src/clients/iterative-query-controller.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2014-2016, Regents of the University of California.
+/*
+ * Copyright (c) 2014-2017, Regents of the University of California.
  *
  * This file is part of NDNS (Named Data Networking Domain Name Service).
  * See AUTHORS.md for complete list of NDNS authors and contributors.
@@ -17,8 +17,8 @@
  * NDNS, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include "validator.hpp"
 #include "iterative-query-controller.hpp"
+#include "validator.hpp"
 #include "logger.hpp"
 #include <iostream>
 
@@ -32,7 +32,7 @@
                                                    const QuerySucceedCallback& onSucceed,
                                                    const QueryFailCallback& onFail,
                                                    Face& face,
-                                                   Validator* validator)
+                                                   security::v2::Validator* validator)
   : QueryController(dstLabel, rrType, interestLifetime, onSucceed, onFail, face)
   , m_validator(validator)
   , m_step(QUERY_STEP_QUERY_NS)
@@ -68,20 +68,20 @@
   NDNS_LOG_TRACE("[* -> *] get a " << contentType
                  << " Response: " << data.getName());
   if (m_validator == nullptr) {
-    this->onDataValidated(make_shared<Data>(data), contentType);
+    this->onDataValidated(data, contentType);
   }
   else {
     m_validator->validate(data,
                           bind(&IterativeQueryController::onDataValidated, this, _1, contentType),
-                          [this] (const shared_ptr<const Data>& data, const std::string& str) {
-                            NDNS_LOG_WARN("data: " << data->getName() << " fails verification");
+                          [this] (const Data& data, const security::v2::ValidationError& err) {
+                            NDNS_LOG_WARN("data: " << data.getName() << " fails verification");
                             this->abort();
                           }
                           );
   }
 }
 void
-IterativeQueryController::onDataValidated(const shared_ptr<const Data>& data, NdnsContentType contentType)
+IterativeQueryController::onDataValidated(const Data& data, NdnsContentType contentType)
 {
   switch (m_step) {
   case QUERY_STEP_QUERY_NS:
@@ -89,11 +89,12 @@
       m_step = QUERY_STEP_QUERY_RR;
     }
     else if (contentType == NDNS_LINK) {
-      Link link(data->wireEncode());
-      if (link.getDelegations().empty()) {
+      Link link(data.wireEncode());
+      if (link.getDelegationList().empty()) {
         m_lastLink = Block();
-      } else {
-        m_lastLink = data->wireEncode();
+      }
+      else {
+        m_lastLink = data.wireEncode();
       }
 
       // for NS query, if already received, just return, instead of more queries until NACK
@@ -113,7 +114,8 @@
       std::ostringstream oss;
       oss << *this;
       NDNS_LOG_WARN("get unexpected Response: NDNS_BLOB for QUERY_NS: " << oss.str());
-    } else {
+    }
+    else {
       std::ostringstream oss;
       oss << *this;
       NDNS_LOG_WARN("get unexpected Response for QUERY_NS: " << oss.str());
@@ -142,9 +144,9 @@
     this->express(this->makeLatestInterest()); // express new Expres
   else if (m_step == QUERY_STEP_ANSWER_STUB) {
     NDNS_LOG_TRACE("query ends: " << *this);
-    Response re = this->parseFinalResponse(*data);
+    Response re = this->parseFinalResponse(data);
     if (m_onSucceed != nullptr)
-      m_onSucceed(*data, re);
+      m_onSucceed(data, re);
     else
       NDNS_LOG_TRACE("succeed callback is nullptr");
   }
@@ -202,7 +204,7 @@
 
   // addLink
   if (m_lastLink.hasWire()) {
-    query.setLink(m_lastLink);
+    query.setDelegationListFromLink(Link(m_lastLink));
   }
 
   switch (m_step) {
@@ -226,7 +228,8 @@
     std::ostringstream oss;
     oss << *this;
     NDNS_LOG_WARN("unexpected state: " << oss.str());
-    throw std::runtime_error("call makeLatestInterest() unexpected: " + oss.str());
+    BOOST_THROW_EXCEPTION(std::runtime_error("call makeLatestInterest() unexpected: "
+                                             + oss.str()));
   }
 
   Interest interest = query.toInterest();
diff --git a/src/clients/iterative-query-controller.hpp b/src/clients/iterative-query-controller.hpp
index 7f975da..8a15d98 100644
--- a/src/clients/iterative-query-controller.hpp
+++ b/src/clients/iterative-query-controller.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2014-2016, Regents of the University of California.
+/*
+ * Copyright (c) 2014-2017, Regents of the University of California.
  *
  * This file is part of NDNS (Named Data Networking Domain Name Service).
  * See AUTHORS.md for complete list of NDNS authors and contributors.
@@ -61,7 +61,7 @@
   IterativeQueryController(const Name& dstLabel, const name::Component& rrType,
                            const time::milliseconds& interestLifetime,
                            const QuerySucceedCallback& onSucceed, const QueryFailCallback& onFail,
-                           Face& face, Validator* validator = nullptr);
+                           Face& face, security::v2::Validator* validator = nullptr);
 
   virtual void
   start();
@@ -78,7 +78,7 @@
   onData(const ndn::Interest& interest, const Data& data);
 
   void
-  onDataValidated(const shared_ptr<const Data>& data, NdnsContentType contentType);
+  onDataValidated(const Data& data, NdnsContentType contentType);
 
   /**
    * @brief change the Controller state according to timeout. For current,
@@ -92,7 +92,7 @@
 
   /**
    * @brief get the Interest according to current Controller state.
-   * Only be valid on State QueryNS & QueryRR, or throw exception
+   * Only be valid on State QueryNS and QueryRR, or throw exception
    */
   const Interest
   makeLatestInterest();
@@ -129,7 +129,7 @@
   }
 
 protected:
-  Validator* m_validator;
+  security::v2::Validator* m_validator;
   /**
    * @brief current query step
    */
@@ -160,4 +160,4 @@
 } // namespace ndns
 } // namespace ndn
 
-#endif // NDNS_CLIENTS_ITERATIVE_QUERY_HPP
+#endif // NDNS_CLIENTS_ITERATIVE_QUERY_CONTROLLER_HPP
diff --git a/src/clients/query.cpp b/src/clients/query.cpp
index 9853672..8a133bb 100644
--- a/src/clients/query.cpp
+++ b/src/clients/query.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2014-2016, Regents of the University of California.
+/*
+ * Copyright (c) 2014-2017, Regents of the University of California.
  *
  * This file is part of NDNS (Named Data Networking Domain Name Service).
  * See AUTHORS.md for complete list of NDNS authors and contributors.
@@ -47,10 +47,11 @@
 
   m_zone = zone;
 
-  if (interest.hasLink()) {
-    m_link = interest.getLink().wireEncode();
-  } else {
-    m_link = Block();
+  if (!interest.getForwardingHint().empty()) {
+    m_delegationList = interest.getForwardingHint();
+  }
+  else {
+    m_delegationList = DelegationList();
   }
 
 
@@ -74,13 +75,19 @@
   Interest interest;
   interest.setName(name);
   interest.setInterestLifetime(m_interestLifetime);
-  if (m_link.hasWire()) {
-    interest.setLink(m_link);
+  if (!m_delegationList.empty()) {
+    interest.setForwardingHint(m_delegationList);
   }
 
   return interest;
 }
 
+void
+Query::setDelegationListFromLink(const Link& link)
+{
+  m_delegationList = link.getDelegationList();
+}
+
 std::ostream&
 operator<<(std::ostream& os, const Query& query)
 {
diff --git a/src/clients/query.hpp b/src/clients/query.hpp
index d96d58c..f933eeb 100644
--- a/src/clients/query.hpp
+++ b/src/clients/query.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2014-2016, Regents of the University of California.
+/*
+ * Copyright (c) 2014-2017, Regents of the University of California.
  *
  * This file is part of NDNS (Named Data Networking Domain Name Service).
  * See AUTHORS.md for complete list of NDNS authors and contributors.
@@ -59,6 +59,9 @@
   bool
   fromInterest(const Name& zone, const Interest& interest);
 
+  void
+  setDelegationListFromLink(const Link& link);
+
   bool
   operator==(const Query& other) const
   {
@@ -170,18 +173,18 @@
    * @brief set link object
    */
   void
-  setLink(const Block& link)
+  setDelegationList(const DelegationList& delegations)
   {
-    m_link = link;
+    m_delegationList = delegations;
   }
 
   /**
    * @brief get Link object
    */
-  const Block&
-  getLink() const
+  const DelegationList&
+  getDelegationList() const
   {
-    return m_link;
+    return m_delegationList;
   }
 
 private:
@@ -190,7 +193,7 @@
   Name m_rrLabel;
   name::Component m_rrType;
   time::milliseconds m_interestLifetime;
-  Block m_link;
+  DelegationList m_delegationList;
 };
 
 std::ostream&
diff --git a/src/clients/response.cpp b/src/clients/response.cpp
index b1c3865..a23bc3c 100644
--- a/src/clients/response.cpp
+++ b/src/clients/response.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2014-2016, Regents of the University of California.
+/*
+ * Copyright (c) 2014-2017, Regents of the University of California.
  *
  * This file is part of NDNS (Named Data Networking Domain Name Service).
  * See AUTHORS.md for complete list of NDNS authors and contributors.
@@ -39,7 +39,7 @@
 {
 }
 
-template<bool T>
+template<encoding::Tag T>
 inline size_t
 Response::wireEncode(EncodingImpl<T>& block) const
 {
@@ -180,8 +180,10 @@
 {
   if (block.type() != ndn::tlv::Content) {
     m_appContent = Block(ndn::tlv::Content, block);
-  } else
+  }
+  else {
     m_appContent = block;
+  }
 
   m_appContent.encode(); // this is a must
 }
diff --git a/src/clients/response.hpp b/src/clients/response.hpp
index 9f2138f..a33e42a 100644
--- a/src/clients/response.hpp
+++ b/src/clients/response.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2014-2016, Regents of the University of California.
+/*
+ * Copyright (c) 2014-2017, Regents of the University of California.
  *
  * This file is part of NDNS (Named Data Networking Domain Name Service).
  * See AUTHORS.md for complete list of NDNS authors and contributors.
@@ -108,9 +108,9 @@
   /**
    * @brief encode app-level data
    */
-  template<bool T>
+  template<encoding::Tag T>
   size_t
-  wireEncode(EncodingImpl<T> & block) const;
+  wireEncode(EncodingImpl<T>& block) const;
 
 public:
   ///////////////////////////////////////////////