diff --git a/src/validator/certificate-fetcher-ndns-appcert.cpp b/src/validator/certificate-fetcher-ndns-appcert.cpp
index e451e96..81f31c6 100644
--- a/src/validator/certificate-fetcher-ndns-appcert.cpp
+++ b/src/validator/certificate-fetcher-ndns-appcert.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2014-2019, Regents of the University of California.
+ * Copyright (c) 2014-2020, 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.
@@ -27,7 +27,7 @@
 namespace ndn {
 namespace ndns {
 
-using security::v2::Certificate;
+using security::Certificate;
 
 CertificateFetcherAppCert::CertificateFetcherAppCert(Face& face,
                                                      size_t nsCacheSize,
@@ -40,8 +40,8 @@
 }
 
 void
-CertificateFetcherAppCert::doFetch(const shared_ptr<security::v2::CertificateRequest>& certRequest,
-                                   const shared_ptr<security::v2::ValidationState>& state,
+CertificateFetcherAppCert::doFetch(const shared_ptr<security::CertificateRequest>& certRequest,
+                                   const shared_ptr<security::ValidationState>& state,
                                    const ValidationContinuation& continueValidation)
 {
   const Name& key = certRequest->interest.getName();
@@ -64,40 +64,40 @@
 
 void
 CertificateFetcherAppCert::onQuerySuccessCallback(const Data& data,
-                                                  const shared_ptr<security::v2::CertificateRequest>& certRequest,
-                                                  const shared_ptr<security::v2::ValidationState>& state,
+                                                  const shared_ptr<security::CertificateRequest>& certRequest,
+                                                  const shared_ptr<security::ValidationState>& state,
                                                   const ValidationContinuation& continueValidation)
 {
   m_validator->validate(data,
                         [=] (const Data& d) {
                           onValidationSuccessCallback(d, certRequest, state, continueValidation);
                         },
-                        [=] (const Data&, const security::v2::ValidationError& err) {
+                        [=] (const Data&, const security::ValidationError& err) {
                           onValidationFailCallback(err, certRequest, state, continueValidation);
                         });
 }
 
 void
 CertificateFetcherAppCert::onQueryFailCallback(const std::string& errMsg,
-                                               const shared_ptr<security::v2::CertificateRequest>& certRequest,
-                                               const shared_ptr<security::v2::ValidationState>& state,
+                                               const shared_ptr<security::CertificateRequest>& certRequest,
+                                               const shared_ptr<security::ValidationState>& state,
                                                const ValidationContinuation& continueValidation)
 {
   state->removeTag<IterativeQueryTag>();
-  state->fail({security::v2::ValidationError::Code::CANNOT_RETRIEVE_CERT, "Cannot fetch certificate due to " +
+  state->fail({security::ValidationError::Code::CANNOT_RETRIEVE_CERT, "Cannot fetch certificate due to " +
                errMsg + " `" + certRequest->interest.getName().toUri() + "`"});
 }
 
 void
 CertificateFetcherAppCert::onValidationSuccessCallback(const Data& data,
-                                                       const shared_ptr<security::v2::CertificateRequest>& certRequest,
-                                                       const shared_ptr<security::v2::ValidationState>& state,
+                                                       const shared_ptr<security::CertificateRequest>& certRequest,
+                                                       const shared_ptr<security::ValidationState>& state,
                                                        const ValidationContinuation& continueValidation)
 {
   state->removeTag<IterativeQueryTag>();
 
   if (data.getContentType() == NDNS_NACK) {
-    return state->fail({security::v2::ValidationError::Code::CANNOT_RETRIEVE_CERT,
+    return state->fail({security::ValidationError::Code::CANNOT_RETRIEVE_CERT,
                         "Cannot fetch certificate: got Nack for query `" +
                         certRequest->interest.getName().toUri() + "`"});
   }
@@ -107,7 +107,7 @@
     cert = Certificate(data.getContent().blockFromValue());
   }
   catch (const ndn::tlv::Error& e) {
-    return state->fail({security::v2::ValidationError::Code::MALFORMED_CERT, "Fetched a malformed "
+    return state->fail({security::ValidationError::Code::MALFORMED_CERT, "Fetched a malformed "
                         "certificate `" + data.getName().toUri() + "` (" + e.what() + ")"});
   }
 
@@ -115,13 +115,13 @@
 }
 
 void
-CertificateFetcherAppCert::onValidationFailCallback(const security::v2::ValidationError& err,
-                                                    const shared_ptr<security::v2::CertificateRequest>& certRequest,
-                                                    const shared_ptr<security::v2::ValidationState>& state,
+CertificateFetcherAppCert::onValidationFailCallback(const security::ValidationError& err,
+                                                    const shared_ptr<security::CertificateRequest>& certRequest,
+                                                    const shared_ptr<security::ValidationState>& state,
                                                     const ValidationContinuation& continueValidation)
 {
   state->removeTag<IterativeQueryTag>();
-  state->fail({security::v2::ValidationError::Code::CANNOT_RETRIEVE_CERT,
+  state->fail({security::ValidationError::Code::CANNOT_RETRIEVE_CERT,
                "Cannot fetch certificate due to NDNS validation error: " +
                err.getInfo() + " `" + certRequest->interest.getName().toUri() + "`"});
 }
diff --git a/src/validator/certificate-fetcher-ndns-appcert.hpp b/src/validator/certificate-fetcher-ndns-appcert.hpp
index 2bd9305..cf8bb35 100644
--- a/src/validator/certificate-fetcher-ndns-appcert.hpp
+++ b/src/validator/certificate-fetcher-ndns-appcert.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2014-2017, Regents of the University of California.
+/*
+ * Copyright (c) 2014-2020, 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.
@@ -21,7 +21,7 @@
 #define NDNS_VALIDATOR_CERTIFICATE_FETCHER_NDNS_APPCERT_HPP
 
 #include <ndn-cxx/ims/in-memory-storage.hpp>
-#include <ndn-cxx/security/v2/validator.hpp>
+#include <ndn-cxx/security/validator.hpp>
 
 namespace ndn {
 namespace ndns {
@@ -31,7 +31,7 @@
  * By an iterative-query process, it will retrieve the record, execute authentications,
  * and de-encapsulate record to get application's certificate.
  */
-class CertificateFetcherAppCert : public security::v2::CertificateFetcher
+class CertificateFetcherAppCert : public security::CertificateFetcher
 {
 public:
   explicit
@@ -47,8 +47,8 @@
    * If validated, de-encapsulate and call continueValidation.
    */
   void
-  doFetch(const shared_ptr<security::v2::CertificateRequest>& certRequest,
-          const shared_ptr<security::v2::ValidationState>& state,
+  doFetch(const shared_ptr<security::CertificateRequest>& certRequest,
+          const shared_ptr<security::ValidationState>& state,
           const ValidationContinuation& continueValidation) override;
 
 private:
@@ -57,8 +57,8 @@
    */
   void
   onQuerySuccessCallback(const Data& data,
-                         const shared_ptr<security::v2::CertificateRequest>& certRequest,
-                         const shared_ptr<security::v2::ValidationState>& state,
+                         const shared_ptr<security::CertificateRequest>& certRequest,
+                         const shared_ptr<security::ValidationState>& state,
                          const ValidationContinuation& continueValidation);
 
   /**
@@ -68,8 +68,8 @@
    */
   void
   onQueryFailCallback(const std::string& errMsg,
-                      const shared_ptr<security::v2::CertificateRequest>& certRequest,
-                      const shared_ptr<security::v2::ValidationState>& state,
+                      const shared_ptr<security::CertificateRequest>& certRequest,
+                      const shared_ptr<security::ValidationState>& state,
                       const ValidationContinuation& continueValidation);
 
   /**
@@ -77,22 +77,22 @@
    */
   void
   onValidationSuccessCallback(const Data& data,
-                              const shared_ptr<security::v2::CertificateRequest>& certRequest,
-                              const shared_ptr<security::v2::ValidationState>& state,
+                              const shared_ptr<security::CertificateRequest>& certRequest,
+                              const shared_ptr<security::ValidationState>& state,
                               const ValidationContinuation& continueValidation);
 
   /**
    * @brief Callback invoked when rrset validation failed
    */
   void
-  onValidationFailCallback(const security::v2::ValidationError& err,
-                           const shared_ptr<security::v2::CertificateRequest>& certRequest,
-                           const shared_ptr<security::v2::ValidationState>& state,
+  onValidationFailCallback(const security::ValidationError& err,
+                           const shared_ptr<security::CertificateRequest>& certRequest,
+                           const shared_ptr<security::ValidationState>& state,
                            const ValidationContinuation& continueValidation);
 
 private:
   Face& m_face;
-  unique_ptr<security::v2::Validator> m_validator;
+  unique_ptr<security::Validator> m_validator;
   InMemoryStorage* m_nsCache;
   size_t m_startComponentIndex;
 };
@@ -100,4 +100,4 @@
 } // namespace ndns
 } // namespace ndn
 
-#endif // NDNS_VALIDATOR_CERTIFICATE_FETCHER_NDNS_APPCERT_HPP
\ No newline at end of file
+#endif // NDNS_VALIDATOR_CERTIFICATE_FETCHER_NDNS_APPCERT_HPP
diff --git a/src/validator/certificate-fetcher-ndns-cert.cpp b/src/validator/certificate-fetcher-ndns-cert.cpp
index bf64515..b1979b5 100644
--- a/src/validator/certificate-fetcher-ndns-cert.cpp
+++ b/src/validator/certificate-fetcher-ndns-cert.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2014-2019, Regents of the University of California.
+ * Copyright (c) 2014-2020, 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.
@@ -28,7 +28,7 @@
 namespace ndn {
 namespace ndns {
 
-using security::v2::Certificate;
+using security::Certificate;
 
 NDNS_LOG_INIT(CertificateFetcherNdnsCert);
 
@@ -42,8 +42,8 @@
 }
 
 void
-CertificateFetcherNdnsCert::doFetch(const shared_ptr<security::v2::CertificateRequest>& certRequest,
-                                    const shared_ptr<security::v2::ValidationState>& state,
+CertificateFetcherNdnsCert::doFetch(const shared_ptr<security::CertificateRequest>& certRequest,
+                                    const shared_ptr<security::ValidationState>& state,
                                     const ValidationContinuation& continueValidation)
 {
   const Name& key = certRequest->interest.getName();
@@ -77,8 +77,8 @@
 
 void
 CertificateFetcherNdnsCert::nsSuccessCallback(const Data& data,
-                                              const shared_ptr<security::v2::CertificateRequest>& certRequest,
-                                              const shared_ptr<security::v2::ValidationState>& state,
+                                              const shared_ptr<security::CertificateRequest>& certRequest,
+                                              const shared_ptr<security::ValidationState>& state,
                                               const ValidationContinuation& continueValidation)
 {
   Name interestName(certRequest->interest.getName());
@@ -113,8 +113,8 @@
 
 void
 CertificateFetcherNdnsCert::nsFailCallback(const std::string& errMsg,
-                                           const shared_ptr<security::v2::CertificateRequest>& certRequest,
-                                           const shared_ptr<security::v2::ValidationState>& state,
+                                           const shared_ptr<security::CertificateRequest>& certRequest,
+                                           const shared_ptr<security::ValidationState>& state,
                                            const ValidationContinuation& continueValidation)
 {
   NDNS_LOG_WARN("Cannot fetch link due to " +
@@ -148,8 +148,8 @@
 
 void
 CertificateFetcherNdnsCert::dataCallback(const Data& data,
-                                         const shared_ptr<security::v2::CertificateRequest>& certRequest,
-                                         const shared_ptr<security::v2::ValidationState>& state,
+                                         const shared_ptr<security::CertificateRequest>& certRequest,
+                                         const shared_ptr<security::ValidationState>& state,
                                          const ValidationContinuation& continueValidation)
 {
   NDNS_LOG_DEBUG("Fetched certificate from network " << data.getName());
@@ -161,7 +161,7 @@
     cert = Certificate(data);
   }
   catch (const ndn::tlv::Error& e) {
-    return state->fail({security::v2::ValidationError::Code::MALFORMED_CERT, "Fetched a malformed "
+    return state->fail({security::ValidationError::Code::MALFORMED_CERT, "Fetched a malformed "
                         "certificate `" + data.getName().toUri() + "` (" + e.what() + ")"});
   }
 
@@ -170,8 +170,8 @@
 
 void
 CertificateFetcherNdnsCert::nackCallback(const lp::Nack& nack,
-                                         const shared_ptr<security::v2::CertificateRequest>& certRequest,
-                                         const shared_ptr<security::v2::ValidationState>& state,
+                                         const shared_ptr<security::CertificateRequest>& certRequest,
+                                         const shared_ptr<security::ValidationState>& state,
                                          const ValidationContinuation& continueValidation)
 {
   NDNS_LOG_DEBUG("NACK (" << nack.getReason() <<  ") while fetching certificate "
@@ -184,14 +184,14 @@
   }
   else {
     state->removeTag<IterativeQueryTag>();
-    state->fail({security::v2::ValidationError::Code::CANNOT_RETRIEVE_CERT, "Cannot fetch certificate "
+    state->fail({security::ValidationError::Code::CANNOT_RETRIEVE_CERT, "Cannot fetch certificate "
                  "after all retries `" + certRequest->interest.getName().toUri() + "`"});
   }
 }
 
 void
-CertificateFetcherNdnsCert::timeoutCallback(const shared_ptr<security::v2::CertificateRequest>& certRequest,
-                                            const shared_ptr<security::v2::ValidationState>& state,
+CertificateFetcherNdnsCert::timeoutCallback(const shared_ptr<security::CertificateRequest>& certRequest,
+                                            const shared_ptr<security::ValidationState>& state,
                                             const ValidationContinuation& continueValidation)
 {
   NDNS_LOG_DEBUG("Timeout while fetching certificate " << certRequest->interest.getName()
@@ -203,7 +203,7 @@
   }
   else {
     state->removeTag<IterativeQueryTag>();
-    state->fail({security::v2::ValidationError::Code::CANNOT_RETRIEVE_CERT, "Cannot fetch certificate "
+    state->fail({security::ValidationError::Code::CANNOT_RETRIEVE_CERT, "Cannot fetch certificate "
                  "after all retries `" + certRequest->interest.getName().toUri() + "`"});
   }
 }
diff --git a/src/validator/certificate-fetcher-ndns-cert.hpp b/src/validator/certificate-fetcher-ndns-cert.hpp
index a67e5b0..f0df918 100644
--- a/src/validator/certificate-fetcher-ndns-cert.hpp
+++ b/src/validator/certificate-fetcher-ndns-cert.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2014-2017, Regents of the University of California.
+/*
+ * Copyright (c) 2014-2020, 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.
@@ -22,7 +22,7 @@
 
 #include <ndn-cxx/face.hpp>
 #include <ndn-cxx/ims/in-memory-storage.hpp>
-#include <ndn-cxx/security/v2/certificate-fetcher.hpp>
+#include <ndn-cxx/security/certificate-fetcher.hpp>
 
 namespace ndn {
 namespace ndns {
@@ -30,7 +30,7 @@
 /**
  * @brief Fetch NDNS-owned certificate by an iterative query process
  */
-class CertificateFetcherNdnsCert : public security::v2::CertificateFetcher
+class CertificateFetcherNdnsCert : public security::CertificateFetcher
 {
 public:
   explicit
@@ -46,8 +46,8 @@
 
 protected:
   void
-  doFetch(const shared_ptr<security::v2::CertificateRequest>& certRequest,
-          const shared_ptr<security::v2::ValidationState>& state,
+  doFetch(const shared_ptr<security::CertificateRequest>& certRequest,
+          const shared_ptr<security::ValidationState>& state,
           const ValidationContinuation& continueValidation) override;
 
 private:
@@ -56,8 +56,8 @@
    */
   void
   nsSuccessCallback(const Data& data,
-                    const shared_ptr<security::v2::CertificateRequest>& certRequest,
-                    const shared_ptr<security::v2::ValidationState>& state,
+                    const shared_ptr<security::CertificateRequest>& certRequest,
+                    const shared_ptr<security::ValidationState>& state,
                     const ValidationContinuation& continueValidation);
 
   /**
@@ -67,8 +67,8 @@
    */
   void
   nsFailCallback(const std::string& errMsg,
-                 const shared_ptr<security::v2::CertificateRequest>& certRequest,
-                 const shared_ptr<security::v2::ValidationState>& state,
+                 const shared_ptr<security::CertificateRequest>& certRequest,
+                 const shared_ptr<security::ValidationState>& state,
                  const ValidationContinuation& continueValidation);
 
   /**
@@ -84,8 +84,8 @@
    */
   void
   dataCallback(const Data& data,
-               const shared_ptr<security::v2::CertificateRequest>& certRequest,
-               const shared_ptr<security::v2::ValidationState>& state,
+               const shared_ptr<security::CertificateRequest>& certRequest,
+               const shared_ptr<security::ValidationState>& state,
                const ValidationContinuation& continueValidation);
   /**
    * @brief Callback invoked when interest for fetching certificate gets NACKed.
@@ -96,8 +96,8 @@
    */
   void
   nackCallback(const lp::Nack& nack,
-               const shared_ptr<security::v2::CertificateRequest>& certRequest,
-               const shared_ptr<security::v2::ValidationState>& state,
+               const shared_ptr<security::CertificateRequest>& certRequest,
+               const shared_ptr<security::ValidationState>& state,
                const ValidationContinuation& continueValidation);
 
   /**
@@ -106,8 +106,8 @@
    * It will retry if certRequest->m_nRetriesLeft > 0
    */
   void
-  timeoutCallback(const shared_ptr<security::v2::CertificateRequest>& certRequest,
-                  const shared_ptr<security::v2::ValidationState>& state,
+  timeoutCallback(const shared_ptr<security::CertificateRequest>& certRequest,
+                  const shared_ptr<security::ValidationState>& state,
                   const ValidationContinuation& continueValidation);
 protected:
   Face& m_face;
@@ -120,4 +120,4 @@
 } // namespace ndns
 } // namespace ndn
 
-#endif // NDNS_VALIDATOR_CERTIFICATE_FETCHER_NDNS_CERT_HPP
\ No newline at end of file
+#endif // NDNS_VALIDATOR_CERTIFICATE_FETCHER_NDNS_CERT_HPP
diff --git a/src/validator/validator.cpp b/src/validator/validator.cpp
index 1e14f92..2be191e 100644
--- a/src/validator/validator.cpp
+++ b/src/validator/validator.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2014-2019, Regents of the University of California.
+ * Copyright (c) 2014-2020, 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.
@@ -22,7 +22,7 @@
 #include "certificate-fetcher-ndns-cert.hpp"
 #include "logger.hpp"
 
-#include <ndn-cxx/security/v2/validation-policy-config.hpp>
+#include <ndn-cxx/security/validation-policy-config.hpp>
 
 namespace ndn {
 namespace ndns {
@@ -31,17 +31,17 @@
 
 std::string NdnsValidatorBuilder::VALIDATOR_CONF_FILE(NDNS_CONFDIR "/validator.conf");
 
-unique_ptr<security::v2::Validator>
+unique_ptr<security::Validator>
 NdnsValidatorBuilder::create(Face& face,
                              size_t nsCacheSize,
                              size_t startComponentIndex,
                              const std::string& confFile)
 {
-  auto validator = make_unique<security::v2::Validator>(make_unique<security::v2::ValidationPolicyConfig>(),
-                                                        make_unique<CertificateFetcherNdnsCert>(face,
-                                                                                                nsCacheSize,
-                                                                                                startComponentIndex));
-  auto& policy = dynamic_cast<security::v2::ValidationPolicyConfig&>(validator->getPolicy());
+  auto validator = make_unique<security::Validator>(make_unique<security::ValidationPolicyConfig>(),
+                                                    make_unique<CertificateFetcherNdnsCert>(face,
+                                                                                            nsCacheSize,
+                                                                                            startComponentIndex));
+  auto& policy = dynamic_cast<security::ValidationPolicyConfig&>(validator->getPolicy());
   policy.load(confFile);
   NDNS_LOG_TRACE("Validator loads configuration: " << confFile);
 
diff --git a/src/validator/validator.hpp b/src/validator/validator.hpp
index 92a4c09..cf3a6bb 100644
--- a/src/validator/validator.hpp
+++ b/src/validator/validator.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2014-2017, Regents of the University of California.
+ * Copyright (c) 2014-2020, 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.
@@ -23,7 +23,7 @@
 #include "config.hpp"
 
 #include <ndn-cxx/data.hpp>
-#include <ndn-cxx/security/v2/validator.hpp>
+#include <ndn-cxx/security/validator.hpp>
 
 namespace ndn {
 namespace ndns {
@@ -33,7 +33,7 @@
 public:
   static std::string VALIDATOR_CONF_FILE;
 
-  static unique_ptr<security::v2::Validator>
+  static unique_ptr<security::Validator>
   create(Face& face,
          size_t nsCacheSize = 500,
          size_t startComponentIndex = 0,