diff --git a/src/ca-module.cpp b/src/ca-module.cpp
index cd28b94..c2072dd 100644
--- a/src/ca-module.cpp
+++ b/src/ca-module.cpp
@@ -35,7 +35,6 @@
 #include <ndn-cxx/util/random.hpp>
 #include <ndn-cxx/util/string-helper.hpp>
 
-namespace ndn {
 namespace ndncert {
 namespace ca {
 
@@ -44,7 +43,7 @@
 
 NDN_LOG_INIT(ndncert.ca);
 
-CaModule::CaModule(Face& face, security::KeyChain& keyChain,
+CaModule::CaModule(ndn::Face& face, ndn::KeyChain& keyChain,
                    const std::string& configPath, const std::string& storageType)
   : m_face(face)
   , m_keyChain(keyChain)
@@ -52,7 +51,7 @@
   // load the config and create storage
   m_config.load(configPath);
   m_storage = CaStorage::createCaStorage(storageType, m_config.caProfile.caPrefix, "");
-  random::generateSecureBytes(m_requestIdGenKey, 32);
+  ndn::random::generateSecureBytes(m_requestIdGenKey, 32);
   if (m_config.nameAssignmentFuncs.size() == 0) {
     m_config.nameAssignmentFuncs.push_back(NameAssignmentFunc::createNameAssignmentFunc("random"));
   }
@@ -80,7 +79,7 @@
     prefix,
     [&] (const Name& name) {
       // register INFO RDR metadata prefix
-      name::Component metaDataComp(32, reinterpret_cast<const uint8_t*>("metadata"), std::strlen("metadata"));
+      ndn::name::Component metaDataComp(32, reinterpret_cast<const uint8_t*>("metadata"), std::strlen("metadata"));
       auto filterId = m_face.setInterestFilter(Name(name).append("INFO").append(metaDataComp),
                                                [this] (auto&&, const auto& i) { onCaProfileDiscovery(i); });
       m_interestFilterHandles.push_back(filterId);
@@ -126,36 +125,29 @@
     const auto& cert = identity.getDefaultKey().getDefaultCertificate();
     Block contentTLV = infotlv::encodeDataContent(m_config.caProfile, cert);
 
-    // set naming convention to be typed
-    auto convention = name::getConventionEncoding();
-    name::setConventionEncoding(name::Convention::TYPED);
-
     Name infoPacketName(m_config.caProfile.caPrefix);
-    auto segmentComp = name::Component::fromSegment(0);
+    auto segmentComp = ndn::name::Component::fromSegment(0);
     infoPacketName.append("CA").append("INFO").appendVersion().append(segmentComp);
     m_profileData = std::make_unique<Data>(infoPacketName);
     m_profileData->setFinalBlock(segmentComp);
     m_profileData->setContent(contentTLV);
     m_profileData->setFreshnessPeriod(DEFAULT_DATA_FRESHNESS_PERIOD);
     m_keyChain.sign(*m_profileData, signingByIdentity(m_config.caProfile.caPrefix));
-
-    // set back the convention
-    name::setConventionEncoding(convention);
   }
   return *m_profileData;
 }
 
 void
-CaModule::onCaProfileDiscovery(const Interest& request)
+CaModule::onCaProfileDiscovery(const Interest&)
 {
   NDN_LOG_TRACE("Received CA Profile MetaData discovery Interest");
   if (m_profileData == nullptr) {
     m_profileData = std::make_unique<Data>(getCaProfileData());
   }
-  MetadataObject metadata;
+  ndn::MetadataObject metadata;
   metadata.setVersionedName(m_profileData->getName().getPrefix(-1));
   Name discoveryInterestName(m_profileData->getName().getPrefix(-2));
-  name::Component metadataComponent(32, reinterpret_cast<const uint8_t*>("metadata"), std::strlen("metadata"));
+  ndn::name::Component metadataComponent(32, reinterpret_cast<const uint8_t*>("metadata"), std::strlen("metadata"));
   discoveryInterestName.append(metadataComponent);
   m_face.put(metadata.makeData(discoveryInterestName, m_keyChain, signingByIdentity(m_config.caProfile.caPrefix)));
 }
@@ -168,7 +160,7 @@
 
   // process PROBE requests: collect probe parameters
   auto parameters = probetlv::decodeApplicationParameters(request.getApplicationParameters());
-  std::vector <PartialName> availableComponents;
+  std::vector<ndn::PartialName> availableComponents;
   for (auto& item : m_config.nameAssignmentFuncs) {
     auto names = item->assignName(parameters);
     availableComponents.insert(availableComponents.end(), names.begin(), names.end());
@@ -216,7 +208,7 @@
   // get ECDH pub key and cert request
   const auto& parameterTLV = request.getApplicationParameters();
   std::vector <uint8_t> ecdhPub;
-  shared_ptr <security::Certificate> clientCert;
+  std::shared_ptr<Certificate> clientCert;
   try {
     requesttlv::decodeApplicationParameters(parameterTLV, requestType, ecdhPub, clientCert);
   }
@@ -256,7 +248,7 @@
 
   // verify identity name
   if (!m_config.caProfile.caPrefix.isPrefixOf(clientCert->getIdentity())
-      || !security::Certificate::isValidName(clientCert->getName())
+      || !Certificate::isValidName(clientCert->getName())
       || clientCert->getIdentity().size() <= m_config.caProfile.caPrefix.size()) {
     NDN_LOG_ERROR("An invalid certificate name is being requested " << clientCert->getName());
     m_face.put(generateErrorDataPacket(request.getName(), ErrorCode::NAME_NOT_ALLOWED,
@@ -286,13 +278,13 @@
     }
 
     // verify signature
-    if (!security::verifySignature(*clientCert, *clientCert)) {
+    if (!ndn::security::verifySignature(*clientCert, *clientCert)) {
       NDN_LOG_ERROR("Invalid signature in the self-signed certificate.");
       m_face.put(generateErrorDataPacket(request.getName(), ErrorCode::BAD_SIGNATURE,
                                          "Invalid signature in the self-signed certificate."));
       return;
     }
-    if (!security::verifySignature(request, *clientCert)) {
+    if (!ndn::security::verifySignature(request, *clientCert)) {
       NDN_LOG_ERROR("Invalid signature in the Interest packet.");
       m_face.put(generateErrorDataPacket(request.getName(), ErrorCode::BAD_SIGNATURE,
                                          "Invalid signature in the Interest packet."));
@@ -301,7 +293,7 @@
   }
   else if (requestType == RequestType::REVOKE) {
     //verify cert is from this CA
-    if (!security::verifySignature(*clientCert, caCert)) {
+    if (!ndn::security::verifySignature(*clientCert, caCert)) {
       NDN_LOG_ERROR("Invalid signature in the certificate to revoke.");
       m_face.put(generateErrorDataPacket(request.getName(), ErrorCode::BAD_SIGNATURE,
                                          "Invalid signature in the certificate to revoke."));
@@ -331,7 +323,7 @@
   requestState.cert = *clientCert;
   // generate salt for HKDF
   std::array<uint8_t, 32> salt;
-  random::generateSecureBytes(salt.data(), salt.size());
+  ndn::random::generateSecureBytes(salt.data(), salt.size());
   // hkdf
   std::array<uint8_t, 16> aesKey;
   hkdf(sharedSecret.data(), sharedSecret.size(), salt.data(), salt.size(),
@@ -340,7 +332,7 @@
   try {
     m_storage->addRequest(requestState);
   }
-  catch (const std::runtime_error& e) {
+  catch (const std::runtime_error&) {
     NDN_LOG_ERROR("Duplicate Request ID: The same request has been seen before.");
     m_face.put(generateErrorDataPacket(request.getName(), ErrorCode::INVALID_PARAMETER,
                                        "Duplicate Request ID: The same request has been seen before."));
@@ -371,14 +363,14 @@
     return;
   }
   // verify signature
-  if (!security::verifySignature(request, requestState->cert)) {
+  if (!ndn::security::verifySignature(request, requestState->cert)) {
     NDN_LOG_ERROR("Invalid Signature in the Interest packet.");
     m_face.put(generateErrorDataPacket(request.getName(), ErrorCode::BAD_SIGNATURE,
                                        "Invalid Signature in the Interest packet."));
     return;
   }
   // decrypt the parameters
-  Buffer paramTLVPayload;
+  ndn::Buffer paramTLVPayload;
   try {
     paramTLVPayload = decodeBlockWithAesGcm128(request.getApplicationParameters(), requestState->encryptionKey.data(),
                                                requestState->requestId.data(), requestState->requestId.size(),
@@ -398,7 +390,7 @@
                                        "No parameters are found after decryption."));
     return;
   }
-  Block paramTLV = makeBinaryBlock(tlv::EncryptedPayload, paramTLVPayload.data(), paramTLVPayload.size());
+  auto paramTLV = ndn::makeBinaryBlock(tlv::EncryptedPayload, paramTLVPayload.data(), paramTLVPayload.size());
   paramTLV.parse();
 
   // load the corresponding challenge module
@@ -457,22 +449,22 @@
   }
 }
 
-security::Certificate
+Certificate
 CaModule::issueCertificate(const RequestState& requestState)
 {
   auto expectedPeriod = requestState.cert.getValidityPeriod().getPeriod();
-  security::ValidityPeriod period(expectedPeriod.first, expectedPeriod.second);
-  security::Certificate newCert;
+  ndn::security::ValidityPeriod period(expectedPeriod.first, expectedPeriod.second);
+  Certificate newCert;
 
   Name certName = requestState.cert.getKeyName();
-  certName.append("NDNCERT").append(std::to_string(random::generateSecureWord64()));
+  certName.append("NDNCERT").append(ndn::to_string(ndn::random::generateSecureWord64()));
   newCert.setName(certName);
   newCert.setContent(requestState.cert.getContent());
   NDN_LOG_TRACE("cert request content " << requestState.cert);
   SignatureInfo signatureInfo;
   signatureInfo.setValidityPeriod(period);
-  security::SigningInfo signingInfo(security::SigningInfo::SIGNER_TYPE_ID,
-                                    m_config.caProfile.caPrefix, signatureInfo);
+  ndn::security::SigningInfo signingInfo(ndn::security::SigningInfo::SIGNER_TYPE_ID,
+                                         m_config.caProfile.caPrefix, signatureInfo);
 
   m_keyChain.sign(newCert, signingInfo);
   NDN_LOG_TRACE("new cert got signed" << newCert);
@@ -492,7 +484,7 @@
     return nullptr;
   }
   try {
-    NDN_LOG_TRACE("Request Id to query the database " << toHex(requestId.data(), requestId.size()));
+    NDN_LOG_TRACE("Request Id to query the database " << ndn::toHex(requestId.data(), requestId.size()));
     return std::make_unique<RequestState>(m_storage->getRequest(requestId));
   }
   catch (const std::exception& e) {
@@ -520,4 +512,3 @@
 
 } // namespace ca
 } // namespace ndncert
-} // namespace ndn
diff --git a/src/ca-module.hpp b/src/ca-module.hpp
index e98638b..88af9f1 100644
--- a/src/ca-module.hpp
+++ b/src/ca-module.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -25,7 +25,9 @@
 #include "detail/crypto-helpers.hpp"
 #include "detail/ca-storage.hpp"
 
-namespace ndn {
+#include <ndn-cxx/face.hpp>
+#include <ndn-cxx/security/key-chain.hpp>
+
 namespace ndncert {
 namespace ca {
 
@@ -37,12 +39,12 @@
  *
  * @param RequestState The state of the certificate request whose status is updated.
  */
-using StatusUpdateCallback = function<void(const RequestState&)>;
+using StatusUpdateCallback = std::function<void(const RequestState&)>;
 
-class CaModule : noncopyable
+class CaModule : boost::noncopyable
 {
 public:
-  CaModule(Face& face, security::KeyChain& keyChain, const std::string& configPath,
+  CaModule(ndn::Face& face, ndn::KeyChain& keyChain, const std::string& configPath,
            const std::string& storageType = "ca-storage-sqlite3");
 
   ~CaModule();
@@ -53,7 +55,7 @@
     return m_config;
   }
 
-  const unique_ptr<CaStorage>&
+  const std::unique_ptr<CaStorage>&
   getCaStorage()
   {
     return m_storage;
@@ -84,7 +86,7 @@
   std::unique_ptr<RequestState>
   getCertificateRequest(const Interest& request);
 
-  security::Certificate
+  Certificate
   issueCertificate(const RequestState& requestState);
 
   void
@@ -94,10 +96,10 @@
   generateErrorDataPacket(const Name& name, ErrorCode error, const std::string& errorInfo);
 
 NDNCERT_PUBLIC_WITH_TESTS_ELSE_PRIVATE:
-  Face& m_face;
+  ndn::Face& m_face;
   CaConfig m_config;
-  unique_ptr<CaStorage> m_storage;
-  security::KeyChain& m_keyChain;
+  std::unique_ptr<CaStorage> m_storage;
+  ndn::KeyChain& m_keyChain;
   uint8_t m_requestIdGenKey[32];
   std::unique_ptr<Data> m_profileData;
   /**
@@ -105,12 +107,11 @@
    */
   StatusUpdateCallback m_statusUpdateCallback;
 
-  std::list<RegisteredPrefixHandle> m_registeredPrefixHandles;
-  std::list<InterestFilterHandle> m_interestFilterHandles;
+  std::list<ndn::RegisteredPrefixHandle> m_registeredPrefixHandles;
+  std::list<ndn::InterestFilterHandle> m_interestFilterHandles;
 };
 
 } // namespace ca
 } // namespace ndncert
-} // namespace ndn
 
 #endif // NDNCERT_CA_MODULE_HPP
diff --git a/src/challenge/challenge-email.cpp b/src/challenge/challenge-email.cpp
index 41d53d6..bc624bc 100644
--- a/src/challenge/challenge-email.cpp
+++ b/src/challenge/challenge-email.cpp
@@ -22,7 +22,6 @@
 #include <regex>
 #include <boost/process.hpp>
 
-namespace ndn {
 namespace ndncert {
 
 NDN_LOG_INIT(ndncert.challenge.email);
@@ -37,8 +36,8 @@
 ChallengeEmail::ChallengeEmail(const std::string& scriptPath,
                                const size_t& maxAttemptTimes,
                                const time::seconds secretLifetime)
-    : ChallengeModule("email", maxAttemptTimes, secretLifetime)
-    , m_sendEmailScript(scriptPath)
+  : ChallengeModule("email", maxAttemptTimes, secretLifetime)
+  , m_sendEmailScript(scriptPath)
 {
 }
 
@@ -52,7 +51,8 @@
     // for the first time, init the challenge
     std::string emailAddress = readString(params.get(tlv::ParameterValue));
     if (!isValidEmailAddress(emailAddress)) {
-      return returnWithNewChallengeStatus(request, INVALID_EMAIL, JsonSection(), m_maxAttemptTimes - 1, m_secretLifetime);
+      return returnWithNewChallengeStatus(request, INVALID_EMAIL, JsonSection(), m_maxAttemptTimes - 1,
+                                          m_secretLifetime);
     }
     auto lastComponentRequested = readString(request.cert.getIdentity().get(-1));
     if (lastComponentRequested != emailAddress) {
@@ -64,8 +64,10 @@
     secretJson.add(PARAMETER_KEY_CODE, emailCode);
     // send out the email
     sendEmail(emailAddress, emailCode, request);
-    NDN_LOG_TRACE("Secret for request " << toHex(request.requestId.data(), request.requestId.size()) << " : " << emailCode);
-    return returnWithNewChallengeStatus(request, NEED_CODE, std::move(secretJson), m_maxAttemptTimes, m_secretLifetime);
+    NDN_LOG_TRACE("Secret for request " << ndn::toHex(request.requestId.data(), request.requestId.size())
+                  << " : " << emailCode);
+    return returnWithNewChallengeStatus(request, NEED_CODE, std::move(secretJson),
+                                        m_maxAttemptTimes, m_secretLifetime);
   }
   if (request.challengeState) {
     if (request.challengeState->challengeStatus == NEED_CODE ||
@@ -134,17 +136,17 @@
     if (params.size() != 1 || params.find(PARAMETER_KEY_EMAIL) == params.end()) {
       NDN_THROW(std::runtime_error("Wrong parameter provided."));
     }
-    request.push_back(makeStringBlock(tlv::SelectedChallenge, CHALLENGE_TYPE));
-    request.push_back(makeStringBlock(tlv::ParameterKey, PARAMETER_KEY_EMAIL));
-    request.push_back(makeStringBlock(tlv::ParameterValue, params.find(PARAMETER_KEY_EMAIL)->second));
+    request.push_back(ndn::makeStringBlock(tlv::SelectedChallenge, CHALLENGE_TYPE));
+    request.push_back(ndn::makeStringBlock(tlv::ParameterKey, PARAMETER_KEY_EMAIL));
+    request.push_back(ndn::makeStringBlock(tlv::ParameterValue, params.find(PARAMETER_KEY_EMAIL)->second));
   }
   else if (status == Status::CHALLENGE && (challengeStatus == NEED_CODE || challengeStatus == WRONG_CODE)) {
     if (params.size() != 1 || params.find(PARAMETER_KEY_CODE) == params.end()) {
       NDN_THROW(std::runtime_error("Wrong parameter provided."));
     }
-    request.push_back(makeStringBlock(tlv::SelectedChallenge, CHALLENGE_TYPE));
-    request.push_back(makeStringBlock(tlv::ParameterKey, PARAMETER_KEY_CODE));
-    request.push_back(makeStringBlock(tlv::ParameterValue, params.find(PARAMETER_KEY_CODE)->second));
+    request.push_back(ndn::makeStringBlock(tlv::SelectedChallenge, CHALLENGE_TYPE));
+    request.push_back(ndn::makeStringBlock(tlv::ParameterKey, PARAMETER_KEY_CODE));
+    request.push_back(ndn::makeStringBlock(tlv::ParameterValue, params.find(PARAMETER_KEY_CODE)->second));
   }
   else {
     NDN_THROW(std::runtime_error("Unexpected status or challenge status."));
@@ -179,4 +181,3 @@
 }
 
 } // namespace ndncert
-} // namespace ndn
diff --git a/src/challenge/challenge-email.hpp b/src/challenge/challenge-email.hpp
index e2c7267..c5d76de 100644
--- a/src/challenge/challenge-email.hpp
+++ b/src/challenge/challenge-email.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -23,7 +23,6 @@
 
 #include "challenge-module.hpp"
 
-namespace ndn {
 namespace ndncert {
 
 /**
@@ -88,6 +87,5 @@
 };
 
 } // namespace ndncert
-} // namespace ndn
 
 #endif // NDNCERT_CHALLENGE_EMAIL_HPP
diff --git a/src/challenge/challenge-module.cpp b/src/challenge/challenge-module.cpp
index f184ca9..bf3b966 100644
--- a/src/challenge/challenge-module.cpp
+++ b/src/challenge/challenge-module.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -21,7 +21,6 @@
 #include "challenge/challenge-module.hpp"
 #include <ndn-cxx/util/random.hpp>
 
-namespace ndn {
 namespace ndncert {
 
 ChallengeModule::ChallengeModule(const std::string& challengeType,
@@ -41,7 +40,7 @@
   return i == factory.end() ? false : true;
 }
 
-unique_ptr<ChallengeModule>
+std::unique_ptr<ChallengeModule>
 ChallengeModule::createChallengeModule(const std::string& challengeType)
 {
   ChallengeFactory& factory = getFactory();
@@ -61,11 +60,11 @@
 {
   uint32_t securityCode = 0;
   do {
-    securityCode = random::generateSecureWord32();
+    securityCode = ndn::random::generateSecureWord32();
   }
   while (securityCode >= 4294000000);
   securityCode /= 4294;
-  std::string result = std::to_string(securityCode);
+  std::string result = ndn::to_string(securityCode);
   while (result.length() < 6) {
     result = "0" + result;
   }
@@ -103,4 +102,3 @@
 }
 
 } // namespace ndncert
-} // namespace ndn
diff --git a/src/challenge/challenge-module.hpp b/src/challenge/challenge-module.hpp
index 9d7d859..1e33bfc 100644
--- a/src/challenge/challenge-module.hpp
+++ b/src/challenge/challenge-module.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -23,16 +23,16 @@
 
 #include "detail/ca-request-state.hpp"
 
-namespace ndn {
 namespace ndncert {
 
-class ChallengeModule : noncopyable
+class ChallengeModule : boost::noncopyable
 {
 public:
   explicit
   ChallengeModule(const std::string& challengeType, size_t maxAttemptTimes, time::seconds secretLifetime);
 
-  virtual ~ChallengeModule() = default;
+  virtual
+  ~ChallengeModule() = default;
 
   template <class ChallengeType>
   static void
@@ -46,7 +46,7 @@
   static bool
   isChallengeSupported(const std::string& challengeType);
 
-  static unique_ptr<ChallengeModule>
+  static std::unique_ptr<ChallengeModule>
   createChallengeModule(const std::string& challengeType);
 
   // For CA
@@ -83,7 +83,7 @@
   const time::seconds m_secretLifetime;
 
 private:
-  typedef function<unique_ptr<ChallengeModule>()> ChallengeCreateFunc;
+  typedef std::function<std::unique_ptr<ChallengeModule>()> ChallengeCreateFunc;
   typedef std::map<std::string, ChallengeCreateFunc> ChallengeFactory;
 
   static ChallengeFactory&
@@ -91,15 +91,15 @@
 };
 
 #define NDNCERT_REGISTER_CHALLENGE(C, T)                              \
-  static class NdnCert##C##ChallengeRegistrationClass {               \
+  static class NdnCert##C##ChallengeRegistrationClass                 \
+  {                                                                   \
   public:                                                             \
     NdnCert##C##ChallengeRegistrationClass()                          \
     {                                                                 \
-      ::ndn::ndncert::ChallengeModule::registerChallengeModule<C>(T); \
+      ::ndncert::ChallengeModule::registerChallengeModule<C>(T);      \
     }                                                                 \
   } g_NdnCert##C##ChallengeRegistrationVariable
 
 } // namespace ndncert
-} // namespace ndn
 
 #endif // NDNCERT_CHALLENGE_MODULE_HPP
diff --git a/src/challenge/challenge-pin.cpp b/src/challenge/challenge-pin.cpp
index 5d3ea8a..6e42969 100644
--- a/src/challenge/challenge-pin.cpp
+++ b/src/challenge/challenge-pin.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -19,9 +19,9 @@
  */
 
 #include "challenge-pin.hpp"
+
 #include <ndn-cxx/util/random.hpp>
 
-namespace ndn {
 namespace ndncert {
 
 NDN_LOG_INIT(ndncert.challenge.pin);
@@ -32,7 +32,7 @@
 const std::string ChallengePin::PARAMETER_KEY_CODE = "code";
 
 ChallengePin::ChallengePin(const size_t& maxAttemptTimes, const time::seconds& secretLifetime)
-    : ChallengeModule("pin", maxAttemptTimes, secretLifetime)
+  : ChallengeModule("pin", maxAttemptTimes, secretLifetime)
 {
 }
 
@@ -48,8 +48,10 @@
     std::string secretCode = generateSecretCode();
     JsonSection secretJson;
     secretJson.add(PARAMETER_KEY_CODE, secretCode);
-    NDN_LOG_TRACE("Secret for request " << toHex(request.requestId.data(), request.requestId.size()) << " : " << secretCode);
-    return returnWithNewChallengeStatus(request, NEED_CODE, std::move(secretJson), m_maxAttemptTimes, m_secretLifetime);
+    NDN_LOG_TRACE("Secret for request " << ndn::toHex(request.requestId.data(), request.requestId.size())
+                  << " : " << secretCode);
+    return returnWithNewChallengeStatus(request, NEED_CODE, std::move(secretJson), m_maxAttemptTimes,
+                                        m_secretLifetime);
   }
   if (request.challengeState) {
     if (request.challengeState->challengeStatus == NEED_CODE ||
@@ -109,15 +111,15 @@
 {
   Block request(tlv::EncryptedPayload);
   if (status == Status::BEFORE_CHALLENGE) {
-    request.push_back(makeStringBlock(tlv::SelectedChallenge, CHALLENGE_TYPE));
+    request.push_back(ndn::makeStringBlock(tlv::SelectedChallenge, CHALLENGE_TYPE));
   }
   else if (status == Status::CHALLENGE && (challengeStatus == NEED_CODE || challengeStatus == WRONG_CODE)) {
     if (params.size() != 1 || params.find(PARAMETER_KEY_CODE) == params.end()) {
       NDN_THROW(std::runtime_error("Wrong parameter provided."));
     }
-    request.push_back(makeStringBlock(tlv::SelectedChallenge, CHALLENGE_TYPE));
-    request.push_back(makeStringBlock(tlv::ParameterKey, PARAMETER_KEY_CODE));
-    request.push_back(makeStringBlock(tlv::ParameterValue, params.find(PARAMETER_KEY_CODE)->second));
+    request.push_back(ndn::makeStringBlock(tlv::SelectedChallenge, CHALLENGE_TYPE));
+    request.push_back(ndn::makeStringBlock(tlv::ParameterKey, PARAMETER_KEY_CODE));
+    request.push_back(ndn::makeStringBlock(tlv::ParameterValue, params.find(PARAMETER_KEY_CODE)->second));
   }
   else {
     NDN_THROW(std::runtime_error("Unexpected status or challenge status."));
@@ -125,5 +127,5 @@
   request.encode();
   return request;
 }
+
 } // namespace ndncert
-} // namespace ndn
diff --git a/src/challenge/challenge-pin.hpp b/src/challenge/challenge-pin.hpp
index 61e0fb6..cfcf508 100644
--- a/src/challenge/challenge-pin.hpp
+++ b/src/challenge/challenge-pin.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -23,7 +23,6 @@
 
 #include "challenge-module.hpp"
 
-namespace ndn {
 namespace ndncert {
 
 /**
@@ -70,6 +69,5 @@
 };
 
 } // namespace ndncert
-} // namespace ndn
 
 #endif // NDNCERT_CHALLENGE_PIN_HPP
diff --git a/src/challenge/challenge-possession.cpp b/src/challenge/challenge-possession.cpp
index ef93d25..a7f0f77 100644
--- a/src/challenge/challenge-possession.cpp
+++ b/src/challenge/challenge-possession.cpp
@@ -27,7 +27,6 @@
 
 #include <boost/property_tree/json_parser.hpp>
 
-namespace ndn {
 namespace ndncert {
 
 NDN_LOG_INIT(ndncert.challenge.possession);
@@ -58,7 +57,7 @@
   }
   catch (const boost::property_tree::file_parser_error& error) {
     NDN_THROW(std::runtime_error("Failed to parse configuration file " + m_configFile + ": " +
-                                 error.message() + " on line " + std::to_string(error.line())));
+                                 error.message() + " on line " + ndn::to_string(error.line())));
   }
 
   if (config.begin() == config.end()) {
@@ -70,7 +69,7 @@
   auto it = anchorList.begin();
   for (; it != anchorList.end(); it++) {
     std::istringstream ss(it->second.get("certificate", ""));
-    auto cert = io::load<security::Certificate>(ss);
+    auto cert = ndn::io::load<Certificate>(ss);
     if (cert == nullptr) {
       NDN_LOG_ERROR("Cannot load the certificate from config file");
       continue;
@@ -87,7 +86,7 @@
   if (m_trustAnchors.empty()) {
     parseConfigFile();
   }
-  security::Certificate credential;
+  Certificate credential;
   const uint8_t* signature = nullptr;
   size_t signatureLen = 0;
   const auto& elements = params.elements();
@@ -113,16 +112,18 @@
   // verify the credential and the self-signed cert
   if (request.status == Status::BEFORE_CHALLENGE) {
     NDN_LOG_TRACE("Challenge Interest arrives. Check certificate and init the challenge");
+    using ndn::toHex;
+
     // check the certificate
     bool checkOK = false;
     if (credential.hasContent() && signatureLen == 0) {
       Name signingKeyName = credential.getSignatureInfo().getKeyLocator().getName();
-      security::transform::PublicKey key;
+      ndn::security::transform::PublicKey key;
       const auto& pubKeyBuffer = credential.getPublicKey();
       key.loadPkcs8(pubKeyBuffer.data(), pubKeyBuffer.size());
       for (auto anchor : m_trustAnchors) {
         if (anchor.getKeyName() == signingKeyName) {
-          if (security::verifySignature(credential, anchor)) {
+          if (ndn::security::verifySignature(credential, anchor)) {
             checkOK = true;
           }
         }
@@ -137,7 +138,7 @@
 
     // for the first time, init the challenge
     std::array<uint8_t, 16> secretCode{};
-    random::generateSecureBytes(secretCode.data(), 16);
+    ndn::random::generateSecureBytes(secretCode.data(), 16);
     JsonSection secretJson;
     secretJson.add(PARAMETER_KEY_NONCE, toHex(secretCode.data(), 16));
     auto credential_block = credential.wireEncode();
@@ -152,14 +153,14 @@
     if (credential.hasContent() || signatureLen == 0) {
       return returnWithError(request, ErrorCode::BAD_INTEREST_FORMAT, "Cannot find certificate");
     }
-    credential = security::Certificate(Block(fromHex(request.challengeState->secrets.get(PARAMETER_KEY_CREDENTIAL_CERT, ""))));
-    auto secretCode = *fromHex(request.challengeState->secrets.get(PARAMETER_KEY_NONCE, ""));
+    credential = Certificate(Block(ndn::fromHex(request.challengeState->secrets.get(PARAMETER_KEY_CREDENTIAL_CERT, ""))));
+    auto secretCode = *ndn::fromHex(request.challengeState->secrets.get(PARAMETER_KEY_NONCE, ""));
 
     //check the proof
-    security::transform::PublicKey key;
+    ndn::security::transform::PublicKey key;
     const auto& pubKeyBuffer = credential.getPublicKey();
     key.loadPkcs8(pubKeyBuffer.data(), pubKeyBuffer.size());
-    if (security::verifySignature({{secretCode.data(), secretCode.size()}}, signature, signatureLen, key)) {
+    if (ndn::security::verifySignature({{secretCode.data(), secretCode.size()}}, signature, signatureLen, key)) {
       return returnWithSuccess(request);
     }
     return returnWithError(request, ErrorCode::INVALID_PARAMETER,
@@ -196,10 +197,10 @@
     if (params.size() != 1) {
       NDN_THROW(std::runtime_error("Wrong parameter provided."));
     }
-    request.push_back(makeStringBlock(tlv::SelectedChallenge, CHALLENGE_TYPE));
+    request.push_back(ndn::makeStringBlock(tlv::SelectedChallenge, CHALLENGE_TYPE));
     for (const auto& item : params) {
       if (std::get<0>(item) == PARAMETER_KEY_CREDENTIAL_CERT) {
-        request.push_back(makeStringBlock(tlv::ParameterKey, PARAMETER_KEY_CREDENTIAL_CERT));
+        request.push_back(ndn::makeStringBlock(tlv::ParameterKey, PARAMETER_KEY_CREDENTIAL_CERT));
         Block valueBlock(tlv::ParameterValue);
         auto& certTlvStr = std::get<1>(item);
         valueBlock.push_back(Block(reinterpret_cast<const uint8_t*>(certTlvStr.data()), certTlvStr.size()));
@@ -210,17 +211,17 @@
       }
     }
   }
-  else if (status == Status::CHALLENGE && challengeStatus == NEED_PROOF){
+  else if (status == Status::CHALLENGE && challengeStatus == NEED_PROOF) {
     if (params.size() != 1) {
       NDN_THROW(std::runtime_error("Wrong parameter provided."));
     }
     for (const auto& item : params) {
       if (std::get<0>(item) == PARAMETER_KEY_PROOF) {
-        request.push_back(makeStringBlock(tlv::ParameterKey, PARAMETER_KEY_PROOF));
+        request.push_back(ndn::makeStringBlock(tlv::ParameterKey, PARAMETER_KEY_PROOF));
         auto& sigTlvStr = std::get<1>(item);
-        Block valueBlock = makeBinaryBlock(tlv::ParameterValue,
-                                           reinterpret_cast<const uint8_t*>(sigTlvStr.data()),
-                                           sigTlvStr.size());
+        auto valueBlock = ndn::makeBinaryBlock(tlv::ParameterValue,
+                                               reinterpret_cast<const uint8_t*>(sigTlvStr.data()),
+                                               sigTlvStr.size());
         request.push_back(valueBlock);
       }
       else {
@@ -237,14 +238,14 @@
 
 void
 ChallengePossession::fulfillParameters(std::multimap<std::string, std::string>& params,
-                                       KeyChain& keyChain, const Name& issuedCertName,
+                                       ndn::KeyChain& keyChain, const Name& issuedCertName,
                                        const std::array<uint8_t, 16>& nonce)
 {
-  auto keyName = security::extractKeyNameFromCertName(issuedCertName);
-  auto id = keyChain.getPib().getIdentity(security::extractIdentityFromCertName(issuedCertName));
+  auto keyName = ndn::security::extractKeyNameFromCertName(issuedCertName);
+  auto id = keyChain.getPib().getIdentity(ndn::security::extractIdentityFromCertName(issuedCertName));
   auto issuedCert = id.getKey(keyName).getCertificate(issuedCertName);
   auto issuedCertTlv = issuedCert.wireEncode();
-  auto signature = keyChain.getTpm().sign({{nonce.data(), nonce.size()}}, keyName, DigestAlgorithm::SHA256);
+  auto signature = keyChain.getTpm().sign({{nonce.data(), nonce.size()}}, keyName, ndn::DigestAlgorithm::SHA256);
 
   for (auto& item : params) {
     if (item.first == PARAMETER_KEY_CREDENTIAL_CERT) {
@@ -257,4 +258,3 @@
 }
 
 } // namespace ndncert
-} // namespace ndn
diff --git a/src/challenge/challenge-possession.hpp b/src/challenge/challenge-possession.hpp
index 165e20e..ab5e641 100644
--- a/src/challenge/challenge-possession.hpp
+++ b/src/challenge/challenge-possession.hpp
@@ -1,5 +1,5 @@
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -22,7 +22,8 @@
 
 #include "challenge-module.hpp"
 
-namespace ndn {
+#include <ndn-cxx/security/key-chain.hpp>
+
 namespace ndncert {
 
 /**
@@ -66,7 +67,8 @@
 
   static void
   fulfillParameters(std::multimap<std::string, std::string>& params,
-                    KeyChain& keyChain, const Name& issuedCertName, const std::array<uint8_t, 16>& nonce);
+                    ndn::KeyChain& keyChain, const Name& issuedCertName,
+                    const std::array<uint8_t, 16>& nonce);
 
   // challenge parameters
   static const std::string PARAMETER_KEY_CREDENTIAL_CERT;
@@ -79,11 +81,10 @@
   parseConfigFile();
 
 NDNCERT_PUBLIC_WITH_TESTS_ELSE_PRIVATE:
-  std::list<security::Certificate> m_trustAnchors;
+  std::list<Certificate> m_trustAnchors;
   std::string m_configFile;
 };
 
 } // namespace ndncert
-} // namespace ndn
 
 #endif // NDNCERT_CHALLENGE_POSSESSION_HPP
diff --git a/src/detail/ca-configuration.cpp b/src/detail/ca-configuration.cpp
index 813c428..a6d26a0 100644
--- a/src/detail/ca-configuration.cpp
+++ b/src/detail/ca-configuration.cpp
@@ -25,7 +25,6 @@
 #include <boost/filesystem.hpp>
 #include <boost/property_tree/json_parser.hpp>
 
-namespace ndn {
 namespace ndncert {
 namespace ca {
 
@@ -57,7 +56,7 @@
         NDN_THROW(std::runtime_error("Redirect-to item's ca-prefix or certificate cannot be empty."));
       }
       std::istringstream ss(caCertStr);
-      auto caCert = io::load<security::Certificate>(ss);
+      auto caCert = ndn::io::load<Certificate>(ss);
       redirection.push_back(caCert);
     }
   }
@@ -77,4 +76,3 @@
 
 } // namespace ca
 } // namespace ndncert
-} // namespace ndn
diff --git a/src/detail/ca-configuration.hpp b/src/detail/ca-configuration.hpp
index ba3de47..2a2a9ff 100644
--- a/src/detail/ca-configuration.hpp
+++ b/src/detail/ca-configuration.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -24,7 +24,6 @@
 #include "detail/ca-profile.hpp"
 #include "name-assignment/assignment-func.hpp"
 
-namespace ndn {
 namespace ndncert {
 namespace ca {
 
@@ -67,7 +66,7 @@
   /**
    * @brief Used for CA redirection
    */
-  std::vector<std::shared_ptr<security::Certificate>> redirection;
+  std::vector<std::shared_ptr<Certificate>> redirection;
   /**
    * @brief Name Assignment Functions
    */
@@ -76,6 +75,5 @@
 
 } // namespace ca
 } // namespace ndncert
-} // namespace ndn
 
 #endif // NDNCERT_DETAIL_CA_CONFIGURATION_HPP
diff --git a/src/detail/ca-memory.cpp b/src/detail/ca-memory.cpp
index 48a0903..eae67cc 100644
--- a/src/detail/ca-memory.cpp
+++ b/src/detail/ca-memory.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2017-2020, Regents of the University of California.
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -19,15 +19,11 @@
  */
 
 #include "detail/ca-memory.hpp"
-#include <ndn-cxx/security/validation-policy.hpp>
 
-namespace ndn {
 namespace ndncert {
 namespace ca {
 
-const std::string
-CaMemory::STORAGE_TYPE = "ca-storage-memory";
-
+const std::string CaMemory::STORAGE_TYPE = "ca-storage-memory";
 NDNCERT_REGISTER_CA_STORAGE(CaMemory);
 
 CaMemory::CaMemory(const Name& caName, const std::string& path)
@@ -40,7 +36,8 @@
 {
   auto search = m_requests.find(requestId);
   if (search == m_requests.end()) {
-    NDN_THROW(std::runtime_error("Request " + toHex(requestId.data(), requestId.size()) + " doest not exists"));
+    NDN_THROW(std::runtime_error("Request " + ndn::toHex(requestId.data(), requestId.size()) +
+                                 " does not exists"));
   }
   return search->second;
 }
@@ -53,7 +50,8 @@
     m_requests.insert(std::make_pair(request.requestId, request));
   }
   else {
-    NDN_THROW(std::runtime_error("Request " + toHex(request.requestId.data(), request.requestId.size()) + " already exists"));
+    NDN_THROW(std::runtime_error("Request " + ndn::toHex(request.requestId.data(), request.requestId.size()) +
+                                 " already exists"));
   }
 }
 
@@ -103,4 +101,3 @@
 
 } // namespace ca
 } // namespace ndncert
-} // namespace ndn
diff --git a/src/detail/ca-memory.hpp b/src/detail/ca-memory.hpp
index d61fc10..6d8b115 100644
--- a/src/detail/ca-memory.hpp
+++ b/src/detail/ca-memory.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2017-2020, Regents of the University of California.
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -23,7 +23,6 @@
 
 #include "detail/ca-storage.hpp"
 
-namespace ndn {
 namespace ndncert {
 namespace ca {
 
@@ -64,6 +63,5 @@
 
 } // namespace ca
 } // namespace ndncert
-} // namespace ndn
 
 #endif // NDNCERT_DETAIL_CA_MEMORY_HPP
diff --git a/src/detail/ca-profile.cpp b/src/detail/ca-profile.cpp
index 0f1ad01..624ec7a 100644
--- a/src/detail/ca-profile.cpp
+++ b/src/detail/ca-profile.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -20,10 +20,11 @@
 
 #include "detail/ca-profile.hpp"
 #include "challenge/challenge-module.hpp"
+
 #include <ndn-cxx/util/io.hpp>
+
 #include <boost/filesystem.hpp>
 
-namespace ndn {
 namespace ndncert {
 
 CaProfile
@@ -79,7 +80,7 @@
   auto certificateStr = json.get(CONFIG_CERTIFICATE, "");
   if (certificateStr != "") {
     std::istringstream ss(certificateStr);
-    profile.cert = io::load<security::Certificate>(ss);
+    profile.cert = ndn::io::load<Certificate>(ss);
   }
   return profile;
 }
@@ -114,11 +115,10 @@
   }
   if (cert != nullptr) {
     std::stringstream ss;
-    io::save(*cert, ss);
+    ndn::io::save(*cert, ss);
     caItem.put("certificate", ss.str());
   }
   return caItem;
 }
 
 } // namespace ndncert
-} // namespace ndn
diff --git a/src/detail/ca-profile.hpp b/src/detail/ca-profile.hpp
index 69adf43..0592be5 100644
--- a/src/detail/ca-profile.hpp
+++ b/src/detail/ca-profile.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -23,7 +23,6 @@
 
 #include "detail/ndncert-common.hpp"
 
-namespace ndn {
 namespace ndncert {
 
 // used in parsing CA configuration file and Client CA profile storage file
@@ -90,10 +89,9 @@
   /**
    * @brief CA's certificate. Only Client side will have m_cert.
    */
-  std::shared_ptr<security::Certificate> cert;
+  std::shared_ptr<Certificate> cert;
 };
 
 } // namespace ndncert
-} // namespace ndn
 
 #endif // NDNCERT_DETAIL_CA_PROFILE_HPP
diff --git a/src/detail/ca-request-state.cpp b/src/detail/ca-request-state.cpp
index b8a6b27..68d189a 100644
--- a/src/detail/ca-request-state.cpp
+++ b/src/detail/ca-request-state.cpp
@@ -24,7 +24,6 @@
 
 #include <boost/property_tree/json_parser.hpp>
 
-namespace ndn {
 namespace ndncert {
 
 std::string statusToString(Status status)
@@ -72,7 +71,7 @@
 operator<<(std::ostream& os, const RequestState& request)
 {
   os << "Request's CA name: " << request.caPrefix << "\n";
-  os << "Request's request ID: " << toHex(request.requestId.data(), request.requestId.size()) << "\n";
+  os << "Request's request ID: " << ndn::toHex(request.requestId.data(), request.requestId.size()) << "\n";
   os << "Request's status: " << statusToString(request.status) << "\n";
   os << "Request's challenge type: " << request.challengeType << "\n";
   if (request.challengeState) {
@@ -85,11 +84,10 @@
     os << "Challenge secret: " << ss.str() << "\n";
   }
   os << "Certificate:\n";
-  util::IndentedStream os2(os, "  ");
+  ndn::util::IndentedStream os2(os, "  ");
   os2 << request.cert;
   return os;
 }
 
 } // namespace ca
 } // namespace ndncert
-} // namespace ndn
diff --git a/src/detail/ca-request-state.hpp b/src/detail/ca-request-state.hpp
index fe4db23..2c4a1d6 100644
--- a/src/detail/ca-request-state.hpp
+++ b/src/detail/ca-request-state.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -22,9 +22,9 @@
 #define NDNCERT_DETAIL_CA_REQUEST_STATE_HPP
 
 #include "detail/ndncert-common.hpp"
+
 #include <array>
 
-namespace ndn {
 namespace ndncert {
 
 typedef std::array<uint8_t, 8> RequestId;
@@ -107,7 +107,7 @@
   /**
    * @brief The self-signed certificate in the request.
    */
-  security::Certificate cert;
+  Certificate cert;
   /**
    * @brief The encryption key for the requester.
    */
@@ -135,6 +135,5 @@
 
 } // namespace ca
 } // namespace ndncert
-} // namespace ndn
 
 #endif // NDNCERT_DETAIL_CA_REQUEST_STATE_HPP
diff --git a/src/detail/ca-sqlite.cpp b/src/detail/ca-sqlite.cpp
index c247501..45cd84d 100644
--- a/src/detail/ca-sqlite.cpp
+++ b/src/detail/ca-sqlite.cpp
@@ -28,16 +28,15 @@
 #include <boost/filesystem.hpp>
 #include <boost/property_tree/json_parser.hpp>
 
-namespace ndn {
 namespace ndncert {
 namespace ca {
 
-using namespace ndn::util;
-const std::string CaSqlite::STORAGE_TYPE = "ca-storage-sqlite3";
+using ndn::util::Sqlite3Statement;
 
+const std::string CaSqlite::STORAGE_TYPE = "ca-storage-sqlite3";
 NDNCERT_REGISTER_CA_STORAGE(CaSqlite);
 
-std::string
+static std::string
 convertJson2String(const JsonSection& json)
 {
   std::stringstream ss;
@@ -45,7 +44,7 @@
   return ss.str();
 }
 
-JsonSection
+static JsonSection
 convertString2Json(const std::string& jsonContent)
 {
   std::istringstream ss(jsonContent);
@@ -54,7 +53,7 @@
   return json;
 }
 
-static const std::string INITIALIZATION = R"_DBTEXT_(
+const std::string INITIALIZATION = R"SQL(
 CREATE TABLE IF NOT EXISTS
   RequestStates(
     id INTEGER PRIMARY KEY,
@@ -75,10 +74,10 @@
   );
 CREATE UNIQUE INDEX IF NOT EXISTS
   RequestStateIdIndex ON RequestStates(request_id);
-)_DBTEXT_";
+)SQL";
 
 CaSqlite::CaSqlite(const Name& caName, const std::string& path)
-    : CaStorage()
+  : CaStorage()
 {
   // Determine the path of sqlite db
   boost::filesystem::path dbDir;
@@ -143,7 +142,7 @@
     state.requestId = requestId;
     state.caPrefix = Name(statement.getBlock(1));
     state.status = static_cast<Status>(statement.getInt(2));
-    state.cert = security::Certificate(statement.getBlock(4));
+    state.cert = Certificate(statement.getBlock(4));
     state.challengeType = statement.getString(5);
     state.requestType = static_cast<RequestType>(statement.getInt(10));
     std::memcpy(state.encryptionKey.data(), statement.getBlob(11), statement.getSize(11));
@@ -158,7 +157,7 @@
     return state;
   }
   else {
-    NDN_THROW(std::runtime_error("Request " + toHex(requestId.data(), requestId.size()) +
+    NDN_THROW(std::runtime_error("Request " + ndn::toHex(requestId.data(), requestId.size()) +
                                  " cannot be fetched from database"));
   }
 }
@@ -189,7 +188,7 @@
     statement.bind(11, request.challengeState->remainingTime.count());
   }
   if (statement.step() != SQLITE_DONE) {
-    NDN_THROW(std::runtime_error("Request " + toHex(request.requestId.data(), request.requestId.size()) +
+    NDN_THROW(std::runtime_error("Request " + ndn::toHex(request.requestId.data(), request.requestId.size()) +
                                  " cannot be added to database"));
   }
 }
@@ -242,7 +241,7 @@
     state.caPrefix = Name(statement.getBlock(2));
     state.status = static_cast<Status>(statement.getInt(3));
     state.challengeType = statement.getString(6);
-    state.cert = security::Certificate(statement.getBlock(5));
+    state.cert = Certificate(statement.getBlock(5));
     state.requestType = static_cast<RequestType>(statement.getInt(11));
     std::memcpy(state.encryptionKey.data(), statement.getBlob(12), statement.getSize(12));
     state.encryptionIv = std::vector<uint8_t>(statement.getBlob(13), statement.getBlob(13) + statement.getSize(13));
@@ -276,7 +275,7 @@
     state.caPrefix = Name(statement.getBlock(2));
     state.status = static_cast<Status>(statement.getInt(3));
     state.challengeType = statement.getString(6);
-    state.cert = security::Certificate(statement.getBlock(5));
+    state.cert = Certificate(statement.getBlock(5));
     state.requestType = static_cast<RequestType>(statement.getInt(11));
     std::memcpy(state.encryptionKey.data(), statement.getBlob(12), statement.getSize(12));
     state.encryptionIv = std::vector<uint8_t>(statement.getBlob(13), statement.getBlob(13) + statement.getSize(13));
@@ -303,4 +302,3 @@
 
 } // namespace ca
 } // namespace ndncert
-} // namespace ndn
diff --git a/src/detail/ca-sqlite.hpp b/src/detail/ca-sqlite.hpp
index 2577a80..969cacf 100644
--- a/src/detail/ca-sqlite.hpp
+++ b/src/detail/ca-sqlite.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2017-2020, Regents of the University of California.
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -25,7 +25,6 @@
 
 struct sqlite3;
 
-namespace ndn {
 namespace ndncert {
 namespace ca {
 
@@ -37,7 +36,7 @@
   explicit
   CaSqlite(const Name& caName, const std::string& path = "");
 
-  ~CaSqlite();
+  ~CaSqlite() override;
 
 public:
   /**
@@ -70,6 +69,5 @@
 
 } // namespace ca
 } // namespace ndncert
-} // namespace ndn
 
 #endif // NDNCERT_DETAIL_CA_SQLITE_HPP
diff --git a/src/detail/ca-storage.cpp b/src/detail/ca-storage.cpp
index a377c6c..24fe38f 100644
--- a/src/detail/ca-storage.cpp
+++ b/src/detail/ca-storage.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -20,11 +20,10 @@
 
 #include "detail/ca-storage.hpp"
 
-namespace ndn {
 namespace ndncert {
 namespace ca {
 
-unique_ptr<CaStorage>
+std::unique_ptr<CaStorage>
 CaStorage::createCaStorage(const std::string& caStorageType, const Name& caName, const std::string& path)
 {
   CaStorageFactory& factory = getFactory();
@@ -41,4 +40,3 @@
 
 } // namespace ca
 } // namespace ndncert
-} // namespace ndn
diff --git a/src/detail/ca-storage.hpp b/src/detail/ca-storage.hpp
index 40166cf..0fa7238 100644
--- a/src/detail/ca-storage.hpp
+++ b/src/detail/ca-storage.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -23,11 +23,10 @@
 
 #include "detail/ca-request-state.hpp"
 
-namespace ndn {
 namespace ndncert {
 namespace ca {
 
-class CaStorage : noncopyable
+class CaStorage : boost::noncopyable
 {
 public: // request related
   /**
@@ -66,14 +65,14 @@
     };
   }
 
-  static unique_ptr<CaStorage>
+  static std::unique_ptr<CaStorage>
   createCaStorage(const std::string& caStorageType, const Name& caName, const std::string& path);
 
   virtual
   ~CaStorage() = default;
 
 private:
-  using CaStorageCreateFunc = function<unique_ptr<CaStorage> (const Name&, const std::string&)>;
+  using CaStorageCreateFunc = std::function<std::unique_ptr<CaStorage> (const Name&, const std::string&)>;
   using CaStorageFactory = std::map<std::string, CaStorageCreateFunc>;
 
   static CaStorageFactory&
@@ -86,12 +85,11 @@
 public:                                                          \
   NdnCert ## C ## CaStorageRegistrationClass()                   \
   {                                                              \
-    ::ndn::ndncert::ca::CaStorage::registerCaStorage<C>();       \
+    ::ndncert::ca::CaStorage::registerCaStorage<C>();            \
   }                                                              \
 } g_NdnCert ## C ## CaStorageRegistrationVariable
 
 } // namespace ca
 } // namespace ndncert
-} // namespace ndn
 
 #endif // NDNCERT_DETAIL_CA_STORAGE_HPP
diff --git a/src/detail/challenge-encoder.cpp b/src/detail/challenge-encoder.cpp
index 11a0168..5d9d46b 100644
--- a/src/detail/challenge-encoder.cpp
+++ b/src/detail/challenge-encoder.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -20,30 +20,30 @@
 
 #include "detail/challenge-encoder.hpp"
 
-namespace ndn {
 namespace ndncert {
 
 Block
 challengetlv::encodeDataContent(ca::RequestState& request, const Name& issuedCertName)
 {
   Block response(tlv::EncryptedPayload);
-  response.push_back(makeNonNegativeIntegerBlock(tlv::Status, static_cast<uint64_t>(request.status)));
+  response.push_back(ndn::makeNonNegativeIntegerBlock(tlv::Status, static_cast<uint64_t>(request.status)));
   if (request.challengeState) {
-    response.push_back(makeStringBlock(tlv::ChallengeStatus, request.challengeState->challengeStatus));
-    response.push_back(makeNonNegativeIntegerBlock(tlv::RemainingTries,
-                                                   request.challengeState->remainingTries));
-    response.push_back(makeNonNegativeIntegerBlock(tlv::RemainingTime,
-                                                   request.challengeState->remainingTime.count()));
+    response.push_back(ndn::makeStringBlock(tlv::ChallengeStatus, request.challengeState->challengeStatus));
+    response.push_back(ndn::makeNonNegativeIntegerBlock(tlv::RemainingTries,
+                                                        request.challengeState->remainingTries));
+    response.push_back(ndn::makeNonNegativeIntegerBlock(tlv::RemainingTime,
+                                                        request.challengeState->remainingTime.count()));
     if (request.challengeState->challengeStatus == "need-proof") {
-      response.push_back(makeStringBlock(tlv::ParameterKey, "nonce"));
-      auto nonce = fromHex(request.challengeState->secrets.get("nonce", ""));
-      response.push_back(makeBinaryBlock(tlv::ParameterValue, nonce->data(), 16));
+      response.push_back(ndn::makeStringBlock(tlv::ParameterKey, "nonce"));
+      auto nonce = ndn::fromHex(request.challengeState->secrets.get("nonce", ""));
+      response.push_back(ndn::makeBinaryBlock(tlv::ParameterValue, nonce->data(), 16));
     }
   }
   if (!issuedCertName.empty()) {
     response.push_back(makeNestedBlock(tlv::IssuedCertName, issuedCertName));
   }
   response.encode();
+
   return encodeBlockWithAesGcm128(ndn::tlv::Content, request.encryptionKey.data(),
                                   response.value(), response.value_size(),
                                   request.requestId.data(), request.requestId.size(),
@@ -56,8 +56,9 @@
   auto result = decodeBlockWithAesGcm128(contentBlock, state.m_aesKey.data(),
                                          state.m_requestId.data(), state.m_requestId.size(),
                                          state.m_decryptionIv, state.m_encryptionIv);
-  auto data = makeBinaryBlock(tlv::EncryptedPayload, result.data(), result.size());
+  auto data = ndn::makeBinaryBlock(tlv::EncryptedPayload, result.data(), result.size());
   data.parse();
+
   state.m_status = statusFromBlock(data.get(tlv::Status));
   if (data.find(tlv::ChallengeStatus) != data.elements_end()) {
     state.m_challengeStatus = readString(data.get(tlv::ChallengeStatus));
@@ -87,4 +88,3 @@
 }
 
 } // namespace ndncert
-} // namespace ndn
diff --git a/src/detail/challenge-encoder.hpp b/src/detail/challenge-encoder.hpp
index a8baa57..2013061 100644
--- a/src/detail/challenge-encoder.hpp
+++ b/src/detail/challenge-encoder.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -24,7 +24,6 @@
 #include "detail/ca-request-state.hpp"
 #include "requester-request.hpp"
 
-namespace ndn {
 namespace ndncert {
 namespace challengetlv {
 
@@ -36,6 +35,5 @@
 
 } // namespace challengetlv
 } // namespace ndncert
-} // namespace ndn
 
-#endif // NDNCERT_DETAIL_CHALLENGE_ENCODER_HPP
\ No newline at end of file
+#endif // NDNCERT_DETAIL_CHALLENGE_ENCODER_HPP
diff --git a/src/detail/crypto-helpers.cpp b/src/detail/crypto-helpers.cpp
index a2a0af5..d0c2e55 100644
--- a/src/detail/crypto-helpers.cpp
+++ b/src/detail/crypto-helpers.cpp
@@ -37,7 +37,6 @@
 
 #include <cstring>
 
-namespace ndn {
 namespace ndncert {
 
 ECDHState::ECDHState()
@@ -416,25 +415,25 @@
 {
   // The spec of AES encrypted payload TLV used in NDNCERT:
   //   https://github.com/named-data/ndncert/wiki/NDNCERT-Protocol-0.3#242-aes-gcm-encryption
-  Buffer encryptedPayload(payloadSize);
+  ndn::Buffer encryptedPayload(payloadSize);
   uint8_t tag[16];
   if (encryptionIv.empty()) {
     encryptionIv.resize(12, 0);
-    random::generateSecureBytes(encryptionIv.data(), 8);
+    ndn::random::generateSecureBytes(encryptionIv.data(), 8);
   }
   size_t encryptedPayloadLen = aesGcm128Encrypt(payload, payloadSize, associatedData, associatedDataSize,
                                                 key, encryptionIv.data(), encryptedPayload.data(), tag);
   Block content(tlvType);
-  content.push_back(makeBinaryBlock(tlv::InitializationVector, encryptionIv.data(), encryptionIv.size()));
-  content.push_back(makeBinaryBlock(tlv::AuthenticationTag, tag, 16));
-  content.push_back(makeBinaryBlock(tlv::EncryptedPayload, encryptedPayload.data(), encryptedPayloadLen));
+  content.push_back(ndn::makeBinaryBlock(tlv::InitializationVector, encryptionIv.data(), encryptionIv.size()));
+  content.push_back(ndn::makeBinaryBlock(tlv::AuthenticationTag, tag, 16));
+  content.push_back(ndn::makeBinaryBlock(tlv::EncryptedPayload, encryptedPayload.data(), encryptedPayloadLen));
   content.encode();
   // update IV's counter
   updateIv(encryptionIv, payloadSize);
   return content;
 }
 
-Buffer
+ndn::Buffer
 decodeBlockWithAesGcm128(const Block& block, const uint8_t* key,
                          const uint8_t* associatedData, size_t associatedDataSize,
                          std::vector<uint8_t>& decryptionIv, const std::vector<uint8_t>& encryptionIv)
@@ -443,7 +442,7 @@
   //   https://github.com/named-data/ndncert/wiki/NDNCERT-Protocol-0.3#242-aes-gcm-encryption
   block.parse();
   const auto& encryptedPayloadBlock = block.get(tlv::EncryptedPayload);
-  Buffer result(encryptedPayloadBlock.value_size());
+  ndn::Buffer result(encryptedPayloadBlock.value_size());
   if (block.get(tlv::InitializationVector).value_size() != 12 ||
       block.get(tlv::AuthenticationTag).value_size() != 16) {
     NDN_THROW(std::runtime_error("Error when decrypting the AES Encrypted Block: "
@@ -478,4 +477,3 @@
 }
 
 } // namespace ndncert
-} // namespace ndn
diff --git a/src/detail/crypto-helpers.hpp b/src/detail/crypto-helpers.hpp
index 9701786..235c6b5 100644
--- a/src/detail/crypto-helpers.hpp
+++ b/src/detail/crypto-helpers.hpp
@@ -25,7 +25,6 @@
 
 #include <openssl/evp.h>
 
-namespace ndn {
 namespace ndncert {
 
 /**
@@ -33,7 +32,7 @@
  *
  * The ECDH is based on prime256v1.
  */
-class ECDHState : noncopyable
+class ECDHState : boost::noncopyable
 {
 public:
   ECDHState();
@@ -169,7 +168,7 @@
  *                     invocations of this function with the same @p key.
  * @return Buffer The plaintext buffer.
  */
-Buffer
+ndn::Buffer
 decodeBlockWithAesGcm128(const Block& block, const uint8_t* key,
                          const uint8_t* associatedData, size_t associatedDataSize,
                          std::vector<uint8_t>& decryptionIv, const std::vector<uint8_t>& encryptionIv);
@@ -183,6 +182,5 @@
 #endif
 
 } // namespace ndncert
-} // namespace ndn
 
 #endif // NDNCERT_DETAIL_CRYPTO_HELPERS_HPP
diff --git a/src/detail/error-encoder.cpp b/src/detail/error-encoder.cpp
index 3fbbdc2..e1e4357 100644
--- a/src/detail/error-encoder.cpp
+++ b/src/detail/error-encoder.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -20,15 +20,14 @@
 
 #include "detail/error-encoder.hpp"
 
-namespace ndn {
 namespace ndncert {
 
 Block
 errortlv::encodeDataContent(ErrorCode errorCode, const std::string& description)
 {
   Block response(ndn::tlv::Content);
-  response.push_back(makeNonNegativeIntegerBlock(tlv::ErrorCode, static_cast<size_t>(errorCode)));
-  response.push_back(makeStringBlock(tlv::ErrorInfo, description));
+  response.push_back(ndn::makeNonNegativeIntegerBlock(tlv::ErrorCode, static_cast<size_t>(errorCode)));
+  response.push_back(ndn::makeStringBlock(tlv::ErrorInfo, description));
   response.encode();
   return response;
 }
@@ -45,4 +44,3 @@
 }
 
 } // namespace ndncert
-} // namespace ndn
diff --git a/src/detail/error-encoder.hpp b/src/detail/error-encoder.hpp
index 67fe80f..3b17353 100644
--- a/src/detail/error-encoder.hpp
+++ b/src/detail/error-encoder.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -23,7 +23,6 @@
 
 #include "detail/ca-profile.hpp"
 
-namespace ndn {
 namespace ndncert {
 namespace errortlv {
 
@@ -41,6 +40,5 @@
 
 } // namespace errortlv
 } // namespace ndncert
-} // namespace ndn
 
-#endif // NDNCERT_DETAIL_ERROR_ENCODER_HPP
\ No newline at end of file
+#endif // NDNCERT_DETAIL_ERROR_ENCODER_HPP
diff --git a/src/detail/info-encoder.cpp b/src/detail/info-encoder.cpp
index 79f617f..e6e6581 100644
--- a/src/detail/info-encoder.cpp
+++ b/src/detail/info-encoder.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -20,11 +20,10 @@
 
 #include "detail/info-encoder.hpp"
 
-namespace ndn {
 namespace ndncert {
 
 Block
-infotlv::encodeDataContent(const CaProfile& caConfig, const security::Certificate& certificate)
+infotlv::encodeDataContent(const CaProfile& caConfig, const Certificate& certificate)
 {
   Block content(ndn::tlv::Content);
   content.push_back(makeNestedBlock(tlv::CaPrefix, caConfig.caPrefix));
@@ -35,11 +34,11 @@
   else {
     caInfo = caConfig.caInfo;
   }
-  content.push_back(makeStringBlock(tlv::CaInfo, caInfo));
+  content.push_back(ndn::makeStringBlock(tlv::CaInfo, caInfo));
   for (const auto& key : caConfig.probeParameterKeys) {
-    content.push_back(makeStringBlock(tlv::ParameterKey, key));
+    content.push_back(ndn::makeStringBlock(tlv::ParameterKey, key));
   }
-  content.push_back(makeNonNegativeIntegerBlock(tlv::MaxValidityPeriod, caConfig.maxValidityPeriod.count()));
+  content.push_back(ndn::makeNonNegativeIntegerBlock(tlv::MaxValidityPeriod, caConfig.maxValidityPeriod.count()));
   content.push_back(makeNestedBlock(tlv::CaCertificate, certificate));
   content.encode();
   return content;
@@ -67,7 +66,7 @@
       break;
     case tlv::CaCertificate:
       item.parse();
-      result.cert = std::make_shared<security::Certificate>(item.get(ndn::tlv::Data));
+      result.cert = std::make_shared<Certificate>(item.get(ndn::tlv::Data));
       break;
     default:
       continue;
@@ -78,4 +77,3 @@
 }
 
 } // namespace ndncert
-} // namespace ndn
\ No newline at end of file
diff --git a/src/detail/info-encoder.hpp b/src/detail/info-encoder.hpp
index 7f9180e..4eaa967 100644
--- a/src/detail/info-encoder.hpp
+++ b/src/detail/info-encoder.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -23,7 +23,6 @@
 
 #include "detail/ca-profile.hpp"
 
-namespace ndn {
 namespace ndncert {
 namespace infotlv {
 
@@ -31,7 +30,7 @@
  * Encode CA configuration and its certificate into a TLV block as INFO Data packet content.
  */
 Block
-encodeDataContent(const CaProfile& caConfig, const security::Certificate& certificate);
+encodeDataContent(const CaProfile& caConfig, const Certificate& certificate);
 
 /**
  * Decode CA configuration from the TLV block of INFO Data packet content.
@@ -41,6 +40,5 @@
 
 } // namespace infotlv
 } // namespace ndncert
-} // namespace ndn
 
-#endif // NDNCERT_DETAIL_INFO_ENCODER_HPP
\ No newline at end of file
+#endif // NDNCERT_DETAIL_INFO_ENCODER_HPP
diff --git a/src/detail/ndncert-common.cpp b/src/detail/ndncert-common.cpp
index 7c210b7..5e22afb 100644
--- a/src/detail/ndncert-common.cpp
+++ b/src/detail/ndncert-common.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -20,7 +20,6 @@
 
 #include "detail/ndncert-common.hpp"
 
-namespace ndn {
 namespace ndncert {
 
 std::ostream&
@@ -56,4 +55,3 @@
 }
 
 } // namespace ndncert
-} // namespace ndn
diff --git a/src/detail/ndncert-common.hpp b/src/detail/ndncert-common.hpp
index 01fa883..d9863a5 100644
--- a/src/detail/ndncert-common.hpp
+++ b/src/detail/ndncert-common.hpp
@@ -41,26 +41,37 @@
 #include <tuple>
 
 #include <ndn-cxx/data.hpp>
-#include <ndn-cxx/encoding/block-helpers.hpp>
 #include <ndn-cxx/encoding/block.hpp>
-#include <ndn-cxx/encoding/tlv.hpp>
-#include <ndn-cxx/face.hpp>
+#include <ndn-cxx/encoding/block-helpers.hpp>
 #include <ndn-cxx/interest.hpp>
-#include <ndn-cxx/lp/nack.hpp>
 #include <ndn-cxx/name.hpp>
 #include <ndn-cxx/security/certificate.hpp>
-#include <ndn-cxx/security/key-chain.hpp>
+#include <ndn-cxx/util/exception.hpp>
 #include <ndn-cxx/util/logger.hpp>
 #include <ndn-cxx/util/optional.hpp>
+#include <ndn-cxx/util/time.hpp>
 
 #include <boost/algorithm/string.hpp>
 #include <boost/assert.hpp>
 #include <boost/noncopyable.hpp>
 #include <boost/property_tree/ptree.hpp>
 
-namespace ndn {
 namespace ndncert {
 
+using ndn::Block;
+using ndn::Data;
+using ndn::Interest;
+using ndn::Name;
+using ndn::SignatureInfo;
+using ndn::security::Certificate;
+
+using ndn::optional;
+using ndn::nullopt;
+
+namespace time = ndn::time;
+using namespace ndn::time_literals;
+using namespace std::string_literals;
+
 namespace tlv {
 
 enum : uint32_t {
@@ -127,6 +138,5 @@
 operator<<(std::ostream& out, RequestType type);
 
 } // namespace ndncert
-} // namespace ndn
 
 #endif // NDNCERT_DETAIL_NDNCERT_COMMON_HPP
diff --git a/src/detail/probe-encoder.cpp b/src/detail/probe-encoder.cpp
index 24471a7..bf51438 100644
--- a/src/detail/probe-encoder.cpp
+++ b/src/detail/probe-encoder.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -20,7 +20,6 @@
 
 #include "detail/probe-encoder.hpp"
 
-namespace ndn {
 namespace ndncert {
 
 Block
@@ -28,8 +27,8 @@
 {
   Block content(ndn::tlv::ApplicationParameters);
   for (const auto& items : parameters) {
-    content.push_back(makeStringBlock(tlv::ParameterKey, items.first));
-    content.push_back(makeStringBlock(tlv::ParameterValue, items.second));
+    content.push_back(ndn::makeStringBlock(tlv::ParameterKey, items.first));
+    content.push_back(ndn::makeStringBlock(tlv::ParameterValue, items.second));
   }
   content.encode();
   return content;
@@ -51,14 +50,14 @@
 
 Block
 probetlv::encodeDataContent(const std::vector<Name>& identifiers, optional<size_t> maxSuffixLength,
-                                std::vector<std::shared_ptr<security::Certificate>> redirectionItems)
+                            std::vector<std::shared_ptr<Certificate>> redirectionItems)
 {
   Block content(ndn::tlv::Content);
   for (const auto& name : identifiers) {
     Block item(tlv::ProbeResponse);
     item.push_back(name.wireEncode());
     if (maxSuffixLength) {
-      item.push_back(makeNonNegativeIntegerBlock(tlv::MaxSuffixLength, *maxSuffixLength));
+      item.push_back(ndn::makeNonNegativeIntegerBlock(tlv::MaxSuffixLength, *maxSuffixLength));
     }
     content.push_back(item);
   }
@@ -71,8 +70,8 @@
 
 void
 probetlv::decodeDataContent(const Block& block,
-                                std::vector<std::pair<Name, int>>& availableNames,
-                                std::vector<Name>& availableRedirection)
+                            std::vector<std::pair<Name, int>>& availableNames,
+                            std::vector<Name>& availableRedirection)
 {
   block.parse();
   for (const auto& item : block.elements()) {
@@ -103,4 +102,3 @@
 }
 
 } // namespace ndncert
-} // namespace ndn
\ No newline at end of file
diff --git a/src/detail/probe-encoder.hpp b/src/detail/probe-encoder.hpp
index 58bcb44..6afe083 100644
--- a/src/detail/probe-encoder.hpp
+++ b/src/detail/probe-encoder.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -23,7 +23,6 @@
 
 #include "detail/ndncert-common.hpp"
 
-namespace ndn {
 namespace ndncert {
 namespace probetlv {
 
@@ -39,14 +38,13 @@
 Block
 encodeDataContent(const std::vector<Name>& identifiers,
                   optional<size_t> maxSuffixLength = nullopt,
-                  std::vector<std::shared_ptr<security::Certificate>> redirectionItems =
-                          std::vector<std::shared_ptr<security::Certificate>>());
+                  std::vector<std::shared_ptr<Certificate>> redirectionItems =
+                          std::vector<std::shared_ptr<Certificate>>());
 
 std::multimap<std::string, std::string>
 decodeApplicationParameters(const Block& block);
 
 } // namespace probetlv
 } // namespace ndncert
-} // namespace ndn
 
-#endif // NDNCERT_DETAIL_PROBE_ENCODER_HPP
\ No newline at end of file
+#endif // NDNCERT_DETAIL_PROBE_ENCODER_HPP
diff --git a/src/detail/profile-storage.cpp b/src/detail/profile-storage.cpp
index 949309a..8ae2bb6 100644
--- a/src/detail/profile-storage.cpp
+++ b/src/detail/profile-storage.cpp
@@ -23,7 +23,6 @@
 #include <boost/filesystem.hpp>
 #include <boost/property_tree/json_parser.hpp>
 
-namespace ndn {
 namespace ndncert {
 namespace requester {
 
@@ -99,4 +98,3 @@
 
 } // namespace requester
 } // namespace ndncert
-} // namespace ndn
diff --git a/src/detail/profile-storage.hpp b/src/detail/profile-storage.hpp
index 5955f15..3df6407 100644
--- a/src/detail/profile-storage.hpp
+++ b/src/detail/profile-storage.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -23,7 +23,6 @@
 
 #include "detail/ca-profile.hpp"
 
-namespace ndn {
 namespace ndncert {
 namespace requester {
 
@@ -69,6 +68,5 @@
 
 } // namespace requester
 } // namespace ndncert
-} // namespace ndn
 
 #endif // NDNCERT_DETAIL_PROFILE_STORAGE_HPP
diff --git a/src/detail/request-encoder.cpp b/src/detail/request-encoder.cpp
index 1801b63..30e2523 100644
--- a/src/detail/request-encoder.cpp
+++ b/src/detail/request-encoder.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -19,20 +19,21 @@
  */
 
 #include "detail/request-encoder.hpp"
+
 #include <ndn-cxx/security/transform/base64-encode.hpp>
 #include <ndn-cxx/security/transform/buffer-source.hpp>
 #include <ndn-cxx/security/transform/stream-sink.hpp>
 
-namespace ndn {
 namespace ndncert {
 
 Block
-requesttlv::encodeApplicationParameters(RequestType requestType, const std::vector <uint8_t>& ecdhPub,
-                                        const security::Certificate& certRequest)
+requesttlv::encodeApplicationParameters(RequestType requestType,
+                                        const std::vector<uint8_t>& ecdhPub,
+                                        const Certificate& certRequest)
 {
   Block
   request(ndn::tlv::ApplicationParameters);
-  request.push_back(makeBinaryBlock(tlv::EcdhPub, ecdhPub.data(), ecdhPub.size()));
+  request.push_back(ndn::makeBinaryBlock(tlv::EcdhPub, ecdhPub.data(), ecdhPub.size()));
   if (requestType == RequestType::NEW || requestType == RequestType::RENEW) {
     request.push_back(makeNestedBlock(tlv::CertRequest, certRequest));
   }
@@ -45,8 +46,8 @@
 
 void
 requesttlv::decodeApplicationParameters(const Block& payload, RequestType requestType,
-                                        std::vector <uint8_t>& ecdhPub,
-                                        shared_ptr <security::Certificate>& clientCert)
+                                        std::vector<uint8_t>& ecdhPub,
+                                        std::shared_ptr<Certificate>& clientCert)
 {
   payload.parse();
 
@@ -63,8 +64,7 @@
   }
   requestPayload.parse();
 
-  security::Certificate cert = security::Certificate(requestPayload.get(ndn::tlv::Data));
-  clientCert = std::make_shared<security::Certificate>(cert);
+  clientCert = std::make_shared<Certificate>(requestPayload.get(ndn::tlv::Data));
 }
 
 Block
@@ -73,11 +73,11 @@
                               const std::vector <std::string>& challenges)
 {
   Block response(ndn::tlv::Content);
-  response.push_back(makeBinaryBlock(tlv::EcdhPub, ecdhKey.data(), ecdhKey.size()));
-  response.push_back(makeBinaryBlock(tlv::Salt, salt.data(), salt.size()));
-  response.push_back(makeBinaryBlock(tlv::RequestId, requestId.data(), requestId.size()));
+  response.push_back(ndn::makeBinaryBlock(tlv::EcdhPub, ecdhKey.data(), ecdhKey.size()));
+  response.push_back(ndn::makeBinaryBlock(tlv::Salt, salt.data(), salt.size()));
+  response.push_back(ndn::makeBinaryBlock(tlv::RequestId, requestId.data(), requestId.size()));
   for (const auto& entry: challenges) {
-    response.push_back(makeStringBlock(tlv::Challenge, entry));
+    response.push_back(ndn::makeStringBlock(tlv::Challenge, entry));
   }
   response.encode();
   return response;
@@ -109,4 +109,3 @@
 }
 
 } // namespace ndncert
-} // namespace ndn
\ No newline at end of file
diff --git a/src/detail/request-encoder.hpp b/src/detail/request-encoder.hpp
index aff7c62..e94571e 100644
--- a/src/detail/request-encoder.hpp
+++ b/src/detail/request-encoder.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -23,17 +23,16 @@
 
 #include "detail/ca-request-state.hpp"
 
-namespace ndn {
 namespace ndncert {
 namespace requesttlv {
 
 Block
 encodeApplicationParameters(RequestType requestType, const std::vector<uint8_t>& ecdhPub,
-                            const security::Certificate& certRequest);
+                            const Certificate& certRequest);
 
 void
 decodeApplicationParameters(const Block& block, RequestType requestType, std::vector<uint8_t>& ecdhPub,
-                            shared_ptr<security::Certificate>& certRequest);
+                            std::shared_ptr<Certificate>& certRequest);
 
 Block
 encodeDataContent(const std::vector<uint8_t>& ecdhKey, const std::array<uint8_t, 32>& salt,
@@ -45,6 +44,5 @@
 
 } // namespace requesttlv
 } // namespace ndncert
-} // namespace ndn
 
-#endif // NDNCERT_DETAIL_NEW_RENEW_REVOKE_ENCODER_HPP
\ No newline at end of file
+#endif // NDNCERT_DETAIL_REQUEST_ENCODER_HPP
diff --git a/src/name-assignment/assignment-func.cpp b/src/name-assignment/assignment-func.cpp
index d65eefd..f4728d3 100644
--- a/src/name-assignment/assignment-func.cpp
+++ b/src/name-assignment/assignment-func.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -19,9 +19,7 @@
  */
 
 #include "assignment-func.hpp"
-#include <ndn-cxx/util/random.hpp>
 
-namespace ndn {
 namespace ndncert {
 
 NameAssignmentFunc::NameAssignmentFunc(const std::string& format)
@@ -39,7 +37,7 @@
   }
 }
 
-unique_ptr<NameAssignmentFunc>
+std::unique_ptr<NameAssignmentFunc>
 NameAssignmentFunc::createNameAssignmentFunc(const std::string& challengeType, const std::string& format)
 {
   CurriedFuncFactory& factory = getFactory();
@@ -55,4 +53,3 @@
 }
 
 } // namespace ndncert
-} // namespace ndn
diff --git a/src/name-assignment/assignment-func.hpp b/src/name-assignment/assignment-func.hpp
index 9e9b128..7f35fcf 100644
--- a/src/name-assignment/assignment-func.hpp
+++ b/src/name-assignment/assignment-func.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -22,12 +22,12 @@
 #define NDNCERT_ASSIGNMENT_FUNC_HPP
 
 #include "detail/ca-request-state.hpp"
+
 #include <map>
 
-namespace ndn {
 namespace ndncert {
 
-class NameAssignmentFunc : noncopyable
+class NameAssignmentFunc : boost::noncopyable
 {
 protected:
   explicit NameAssignmentFunc(const std::string& format = "");
@@ -45,7 +45,7 @@
    * @param vector A list of parameter key-value pair used for name assignment.
    * @return a vector containing the possible namespaces derived from the parameters.
    */
-  virtual std::vector<PartialName>
+  virtual std::vector<ndn::PartialName>
   assignName(const std::multimap<std::string, std::string>& params) = 0;
 
 public:
@@ -58,14 +58,14 @@
     factory[typeName] = [](const std::string& format) { return std::make_unique<AssignmentType>(format); };
   }
 
-  static unique_ptr<NameAssignmentFunc>
+  static std::unique_ptr<NameAssignmentFunc>
   createNameAssignmentFunc(const std::string& challengeType, const std::string& format = "");
 
 NDNCERT_PUBLIC_WITH_TESTS_ELSE_PROTECTED:
   std::vector<std::string> m_nameFormat;
 
 private:
-  typedef function<unique_ptr<NameAssignmentFunc>(const std::string&)> FactoryCreateFunc;
+  typedef std::function<std::unique_ptr<NameAssignmentFunc>(const std::string&)> FactoryCreateFunc;
   typedef std::map<std::string, FactoryCreateFunc> CurriedFuncFactory;
 
   static CurriedFuncFactory&
@@ -73,15 +73,15 @@
 };
 
 #define NDNCERT_REGISTER_FUNCFACTORY(C, T)                                        \
-  static class NdnCert##C##FuncFactoryRegistrationClass {                         \
+  static class NdnCert##C##FuncFactoryRegistrationClass                           \
+  {                                                                               \
   public:                                                                         \
     NdnCert##C##FuncFactoryRegistrationClass()                                    \
     {                                                                             \
-      ::ndn::ndncert::NameAssignmentFunc::registerNameAssignmentFunc<C>(T);       \
+      ::ndncert::NameAssignmentFunc::registerNameAssignmentFunc<C>(T);            \
     }                                                                             \
   } g_NdnCert##C##ChallengeRegistrationVariable
 
 } // namespace ndncert
-} // namespace ndn
 
 #endif // NDNCERT_ASSIGNMENT_FUNC_HPP
diff --git a/src/name-assignment/assignment-hash.cpp b/src/name-assignment/assignment-hash.cpp
index f292821..f406619 100644
--- a/src/name-assignment/assignment-hash.cpp
+++ b/src/name-assignment/assignment-hash.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -19,26 +19,27 @@
  */
 
 #include "assignment-hash.hpp"
+
 #include <ndn-cxx/util/sha256.hpp>
 
-namespace ndn {
 namespace ndncert {
 
 NDNCERT_REGISTER_FUNCFACTORY(AssignmentHash, "hash");
 
 AssignmentHash::AssignmentHash(const std::string& format)
   : NameAssignmentFunc(format)
-{}
+{
+}
 
-std::vector<PartialName>
+std::vector<ndn::PartialName>
 AssignmentHash::assignName(const std::multimap<std::string, std::string>& params)
 {
-  std::vector<PartialName> resultList;
+  std::vector<ndn::PartialName> resultList;
   Name result;
   for (const auto& item : m_nameFormat) {
     auto it = params.find(item);
     if (it != params.end()) {
-      util::Sha256 digest;
+      ndn::util::Sha256 digest;
       digest << it->second;
       result.append(digest.toString());
     }
@@ -51,4 +52,3 @@
 }
 
 } // namespace ndncert
-} // namespace ndn
diff --git a/src/name-assignment/assignment-hash.hpp b/src/name-assignment/assignment-hash.hpp
index 83acc28..66d3984 100644
--- a/src/name-assignment/assignment-hash.hpp
+++ b/src/name-assignment/assignment-hash.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -23,7 +23,6 @@
 
 #include "assignment-func.hpp"
 
-namespace ndn {
 namespace ndncert {
 
 /**
@@ -34,12 +33,10 @@
 public:
   AssignmentHash(const std::string& format = "");
 
-  std::vector<PartialName>
+  std::vector<ndn::PartialName>
   assignName(const std::multimap<std::string, std::string>& params) override;
-
 };
 
 } // namespace ndncert
-} // namespace ndn
 
 #endif // NDNCERT_ASSIGNMENT_HASH_HPP
diff --git a/src/name-assignment/assignment-param.cpp b/src/name-assignment/assignment-param.cpp
index 53022cc..956b3d8 100644
--- a/src/name-assignment/assignment-param.cpp
+++ b/src/name-assignment/assignment-param.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -20,19 +20,19 @@
 
 #include "assignment-param.hpp"
 
-namespace ndn {
 namespace ndncert {
 
 NDNCERT_REGISTER_FUNCFACTORY(AssignmentParam, "param");
 
 AssignmentParam::AssignmentParam(const std::string& format)
   : NameAssignmentFunc(format)
-{}
+{
+}
 
-std::vector<PartialName>
+std::vector<ndn::PartialName>
 AssignmentParam::assignName(const std::multimap<std::string, std::string>& params)
 {
-  std::vector<PartialName> resultList;
+  std::vector<ndn::PartialName> resultList;
   Name result;
   for (const auto& item : m_nameFormat) {
     auto it = std::find_if(params.begin(), params.end(),
@@ -49,4 +49,3 @@
 }
 
 } // namespace ndncert
-} // namespace ndn
diff --git a/src/name-assignment/assignment-param.hpp b/src/name-assignment/assignment-param.hpp
index 52bcb80..fc77d27 100644
--- a/src/name-assignment/assignment-param.hpp
+++ b/src/name-assignment/assignment-param.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -23,7 +23,6 @@
 
 #include "assignment-func.hpp"
 
-namespace ndn {
 namespace ndncert {
 
 /**
@@ -34,12 +33,10 @@
 public:
   AssignmentParam(const std::string& format = "");
 
-  std::vector<PartialName>
+  std::vector<ndn::PartialName>
   assignName(const std::multimap<std::string, std::string>& params) override;
-
 };
 
 } // namespace ndncert
-} // namespace ndn
 
 #endif // NDNCERT_ASSIGNMENT_PARAM_HPP
diff --git a/src/name-assignment/assignment-random.cpp b/src/name-assignment/assignment-random.cpp
index 284a1f7..3305cae 100644
--- a/src/name-assignment/assignment-random.cpp
+++ b/src/name-assignment/assignment-random.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -19,24 +19,22 @@
  */
 
 #include "assignment-random.hpp"
+
 #include <ndn-cxx/util/random.hpp>
 
-namespace ndn {
 namespace ndncert {
 
 NDNCERT_REGISTER_FUNCFACTORY(AssignmentRandom, "random");
 
 AssignmentRandom::AssignmentRandom(const std::string& format)
   : NameAssignmentFunc(format)
-{}
-
-std::vector<PartialName>
-AssignmentRandom::assignName(const std::multimap<std::string, std::string>& params)
 {
-  std::vector<PartialName> resultList;
-  resultList.emplace_back(to_string(random::generateSecureWord64()));
-  return resultList;
+}
+
+std::vector<ndn::PartialName>
+AssignmentRandom::assignName(const std::multimap<std::string, std::string>&)
+{
+  return {ndn::PartialName(ndn::to_string(ndn::random::generateSecureWord64()))};
 }
 
 } // namespace ndncert
-} // namespace ndn
diff --git a/src/name-assignment/assignment-random.hpp b/src/name-assignment/assignment-random.hpp
index 86f8096..872c784 100644
--- a/src/name-assignment/assignment-random.hpp
+++ b/src/name-assignment/assignment-random.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -23,7 +23,6 @@
 
 #include "assignment-func.hpp"
 
-namespace ndn {
 namespace ndncert {
 
 /**
@@ -34,11 +33,10 @@
 public:
   AssignmentRandom(const std::string& format = "");
 
-  std::vector<PartialName>
+  std::vector<ndn::PartialName>
   assignName(const std::multimap<std::string, std::string>& params) override;
 };
 
 } // namespace ndncert
-} // namespace ndn
 
 #endif // NDNCERT_ASSIGNMENT_RANDOM_HPP
diff --git a/src/requester-request.cpp b/src/requester-request.cpp
index 5929794..6ab56ea 100644
--- a/src/requester-request.cpp
+++ b/src/requester-request.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -19,6 +19,7 @@
  */
 
 #include "requester-request.hpp"
+
 #include "challenge/challenge-module.hpp"
 #include "detail/crypto-helpers.hpp"
 #include "detail/challenge-encoder.hpp"
@@ -26,6 +27,8 @@
 #include "detail/info-encoder.hpp"
 #include "detail/request-encoder.hpp"
 #include "detail/probe-encoder.hpp"
+
+#include <ndn-cxx/metadata-object.hpp>
 #include <ndn-cxx/security/signing-helpers.hpp>
 #include <ndn-cxx/security/transform/base64-encode.hpp>
 #include <ndn-cxx/security/transform/buffer-source.hpp>
@@ -33,41 +36,32 @@
 #include <ndn-cxx/security/verification-helpers.hpp>
 #include <ndn-cxx/util/io.hpp>
 #include <ndn-cxx/util/random.hpp>
-#include <ndn-cxx/metadata-object.hpp>
+
 #include <boost/lexical_cast.hpp>
 
-namespace ndn {
 namespace ndncert {
 namespace requester {
 
 NDN_LOG_INIT(ndncert.client);
 
-shared_ptr<Interest>
+std::shared_ptr<Interest>
 Request::genCaProfileDiscoveryInterest(const Name& caName)
 {
   Name contentName = caName;
   if (readString(caName.at(-1)) != "CA")
     contentName.append("CA");
   contentName.append("INFO");
-  return std::make_shared<Interest>(MetadataObject::makeDiscoveryInterest(contentName));
+  return std::make_shared<Interest>(ndn::MetadataObject::makeDiscoveryInterest(contentName));
 }
 
-shared_ptr<Interest>
+std::shared_ptr<Interest>
 Request::genCaProfileInterestFromDiscoveryResponse(const Data& reply)
 {
-  // set naming convention to be typed
-  auto convention = name::getConventionEncoding();
-  name::setConventionEncoding(name::Convention::TYPED);
-
-  auto metaData = MetadataObject(reply);
+  auto metaData = ndn::MetadataObject(reply);
   auto interestName= metaData.getVersionedName();
   interestName.appendSegment(0);
   auto interest = std::make_shared<Interest>(interestName);
   interest->setCanBePrefix(false);
-
-  // set back the convention
-  name::setConventionEncoding(convention);
-
   return interest;
 }
 
@@ -75,7 +69,7 @@
 Request::onCaProfileResponse(const Data& reply)
 {
   auto caItem = infotlv::decodeDataContent(reply.getContent());
-  if (!security::verifySignature(reply, *caItem.cert)) {
+  if (!ndn::security::verifySignature(reply, *caItem.cert)) {
     NDN_LOG_ERROR("Cannot verify replied Data packet signature.");
     NDN_THROW(std::runtime_error("Cannot verify replied Data packet signature."));
   }
@@ -87,7 +81,7 @@
 {
   auto caItem = infotlv::decodeDataContent(reply.getContent());
   auto certBlock = caItem.cert->wireEncode();
-  caItem.cert = std::make_shared<security::Certificate>(certBlock);
+  caItem.cert = std::make_shared<Certificate>(certBlock);
   if (caItem.cert->getFullName() != caCertFullName) {
     NDN_LOG_ERROR("Ca profile does not match the certificate information offered by the original CA.");
     NDN_THROW(std::runtime_error("Cannot verify replied Data packet signature."));
@@ -95,12 +89,12 @@
   return onCaProfileResponse(reply);
 }
 
-shared_ptr<Interest>
+std::shared_ptr<Interest>
 Request::genProbeInterest(const CaProfile& ca, std::multimap<std::string, std::string>&& probeInfo)
 {
   Name interestName = ca.caPrefix;
   interestName.append("CA").append("PROBE");
-  auto interest =std::make_shared<Interest>(interestName);
+  auto interest = std::make_shared<Interest>(interestName);
   interest->setMustBeFresh(true);
   interest->setCanBePrefix(false);
   interest->setApplicationParameters(probetlv::encodeApplicationParameters(std::move(probeInfo)));
@@ -111,7 +105,7 @@
 Request::onProbeResponse(const Data& reply, const CaProfile& ca,
                          std::vector<std::pair<Name, int>>& identityNames, std::vector<Name>& otherCas)
 {
-  if (!security::verifySignature(reply, *ca.cert)) {
+  if (!ndn::security::verifySignature(reply, *ca.cert)) {
     NDN_LOG_ERROR("Cannot verify replied Data packet signature.");
     NDN_THROW(std::runtime_error("Cannot verify replied Data packet signature."));
     return;
@@ -120,13 +114,14 @@
   probetlv::decodeDataContent(reply.getContent(), identityNames, otherCas);
 }
 
-Request::Request(security::KeyChain& keyChain, const CaProfile& profile, RequestType requestType)
-    : m_caProfile(profile)
-    , m_type(requestType)
-    , m_keyChain(keyChain)
-{}
+Request::Request(ndn::KeyChain& keyChain, const CaProfile& profile, RequestType requestType)
+  : m_caProfile(profile)
+  , m_type(requestType)
+  , m_keyChain(keyChain)
+{
+}
 
-shared_ptr<Interest>
+std::shared_ptr<Interest>
 Request::genNewInterest(const Name& newIdentityName,
                         const time::system_clock::TimePoint& notBefore,
                         const time::system_clock::TimePoint& notAfter)
@@ -137,7 +132,7 @@
   if (newIdentityName.empty()) {
     NDN_LOG_TRACE("Randomly create a new name because newIdentityName is empty and the param is empty.");
     m_identityName = m_caProfile.caPrefix;
-    m_identityName.append(std::to_string(random::generateSecureWord64()));
+    m_identityName.append(ndn::to_string(ndn::random::generateSecureWord64()));
   }
   else {
     m_identityName = newIdentityName;
@@ -145,11 +140,11 @@
 
   // generate a newly key pair or use an existing key
   const auto& pib = m_keyChain.getPib();
-  security::pib::Identity identity;
+  ndn::security::pib::Identity identity;
   try {
     identity = pib.getIdentity(m_identityName);
   }
-  catch (const security::Pib::Error& e) {
+  catch (const ndn::security::Pib::Error&) {
     identity = m_keyChain.createIdentity(m_identityName);
     m_isNewlyCreatedIdentity = true;
     m_isNewlyCreatedKey = true;
@@ -157,19 +152,19 @@
   try {
     m_keyPair = identity.getDefaultKey();
   }
-  catch (const security::Pib::Error& e) {
+  catch (const ndn::security::Pib::Error&) {
     m_keyPair = m_keyChain.createKey(identity);
     m_isNewlyCreatedKey = true;
   }
   auto& keyName = m_keyPair.getName();
 
   // generate certificate request
-  security::Certificate certRequest;
+  Certificate certRequest;
   certRequest.setName(Name(keyName).append("cert-request").appendVersion());
   certRequest.setContentType(ndn::tlv::ContentType_Key);
   certRequest.setContent(m_keyPair.getPublicKey().data(), m_keyPair.getPublicKey().size());
   SignatureInfo signatureInfo;
-  signatureInfo.setValidityPeriod(security::ValidityPeriod(notBefore, notAfter));
+  signatureInfo.setValidityPeriod(ndn::security::ValidityPeriod(notBefore, notAfter));
   m_keyChain.sign(certRequest, signingByKey(keyName).setSignatureInfo(signatureInfo));
 
   // generate Interest packet
@@ -186,8 +181,8 @@
   return interest;
 }
 
-shared_ptr<Interest>
-Request::genRevokeInterest(const security::Certificate& certificate)
+std::shared_ptr<Interest>
+Request::genRevokeInterest(const Certificate& certificate)
 {
   if (!m_caProfile.caPrefix.isPrefixOf(certificate.getName())) {
     return nullptr;
@@ -206,7 +201,7 @@
 std::list<std::string>
 Request::onNewRenewRevokeResponse(const Data& reply)
 {
-  if (!security::verifySignature(reply, *m_caProfile.cert)) {
+  if (!ndn::security::verifySignature(reply, *m_caProfile.cert)) {
     NDN_LOG_ERROR("Cannot verify replied Data packet signature.");
     NDN_THROW(std::runtime_error("Cannot verify replied Data packet signature."));
   }
@@ -238,7 +233,7 @@
   return challenge->getRequestedParameterList(m_status, m_challengeStatus);
 }
 
-shared_ptr<Interest>
+std::shared_ptr<Interest>
 Request::genChallengeInterest(std::multimap<std::string, std::string>&& parameters)
 {
   if (m_challengeType == "") {
@@ -269,7 +264,7 @@
 void
 Request::onChallengeResponse(const Data& reply)
 {
-  if (!security::verifySignature(reply, *m_caProfile.cert)) {
+  if (!ndn::security::verifySignature(reply, *m_caProfile.cert)) {
     NDN_LOG_ERROR("Cannot verify replied Data packet signature.");
     NDN_THROW(std::runtime_error("Cannot verify replied Data packet signature."));
   }
@@ -277,23 +272,23 @@
   challengetlv::decodeDataContent(reply.getContent(), *this);
 }
 
-shared_ptr<Interest>
+std::shared_ptr<Interest>
 Request::genCertFetchInterest() const
 {
   Name interestName = m_issuedCertName;
-  auto interest =std::make_shared<Interest>(interestName);
+  auto interest = std::make_shared<Interest>(interestName);
   interest->setMustBeFresh(false);
   interest->setCanBePrefix(false);
   return interest;
 }
 
-shared_ptr<security::Certificate>
+std::shared_ptr<Certificate>
 Request::onCertFetchResponse(const Data& reply)
 {
   try {
-    return std::make_shared<security::Certificate>(reply);
+    return std::make_shared<Certificate>(reply);
   }
-  catch (const std::exception& e) {
+  catch (const std::exception&) {
     NDN_LOG_ERROR("Cannot parse replied certificate ");
     NDN_THROW(std::runtime_error("Cannot parse replied certificate "));
     return nullptr;
@@ -334,4 +329,3 @@
 
 } // namespace requester
 } // namespace ndncert
-} // namespace ndn
diff --git a/src/requester-request.hpp b/src/requester-request.hpp
index a1817ea..acd06cc 100644
--- a/src/requester-request.hpp
+++ b/src/requester-request.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -25,11 +25,12 @@
 #include "detail/crypto-helpers.hpp"
 #include "detail/profile-storage.hpp"
 
-namespace ndn {
+#include <ndn-cxx/security/key-chain.hpp>
+
 namespace ndncert {
 namespace requester {
 
-class Request : noncopyable
+class Request : boost::noncopyable
 {
 public:
   /**
@@ -38,7 +39,7 @@
    * @param caName The name prefix of the CA.
    * @return A shared pointer to an Interest ready to be sent.
    */
-  static shared_ptr<Interest>
+  static std::shared_ptr<Interest>
   genCaProfileDiscoveryInterest(const Name& caName);
 
   /**
@@ -47,7 +48,7 @@
    * @param reply The Data packet replied from discovery Interest.
    * @return A shared pointer to an Interest ready to be sent.
    */
-  static shared_ptr<Interest>
+  static std::shared_ptr<Interest>
   genCaProfileInterestFromDiscoveryResponse(const Data& reply);
 
   /**
@@ -85,7 +86,7 @@
    * @param probeInfo The requester information to carry to the CA
    * @return A shared pointer of to the encoded interest, ready to be sent.
    */
-  static shared_ptr<Interest>
+  static std::shared_ptr<Interest>
   genProbeInterest(const CaProfile& ca, std::multimap<std::string, std::string>&& probeInfo);
 
   /**
@@ -103,9 +104,8 @@
   onProbeResponse(const Data& reply, const CaProfile& ca,
                   std::vector<std::pair<Name, int>>& identityNames, std::vector<Name>& otherCas);
 
-
   explicit
-  Request(security::KeyChain& keyChain, const CaProfile& profile, RequestType requestType);
+  Request(ndn::KeyChain& keyChain, const CaProfile& profile, RequestType requestType);
 
   // NEW/REVOKE/RENEW related helpers
   /**
@@ -117,7 +117,7 @@
    * @param notAfter The expected notAfter field for the certificate (expiration time)
    * @return The shared pointer to the encoded interest.
    */
-  shared_ptr<Interest>
+  std::shared_ptr<Interest>
   genNewInterest(const Name& newIdentityName,
                  const time::system_clock::TimePoint& notBefore,
                  const time::system_clock::TimePoint& notAfter);
@@ -129,8 +129,8 @@
    * @param certificate The certificate to the revoked.
    * @return The shared pointer to the encoded interest.
    */
-  shared_ptr<Interest>
-  genRevokeInterest(const security::Certificate& certificate);
+  std::shared_ptr<Interest>
+  genRevokeInterest(const Certificate& certificate);
 
   /**
    * @brief Decodes the replied data of NEW, RENEW, or REVOKE interest from the CA.
@@ -164,7 +164,7 @@
    * @return The shared pointer to the encoded interest
    * @throw std::runtime_error if the challenge is not selected or is not supported.
    */
-  shared_ptr<Interest>
+  std::shared_ptr<Interest>
   genChallengeInterest(std::multimap<std::string, std::string>&& parameters);
 
   /**
@@ -183,7 +183,7 @@
    * @param state, the state of the request.
    * @return The shared pointer to the encoded interest
    */
-  shared_ptr<Interest>
+  std::shared_ptr<Interest>
   genCertFetchInterest() const;
 
   /**
@@ -192,7 +192,7 @@
    * @param reply, the data replied from the certificate fetch interest.
    * @return The shared pointer to the certificate being fetched.
    */
-  static shared_ptr<security::Certificate>
+  static std::shared_ptr<Certificate>
   onCertFetchResponse(const Data& reply);
 
   /**
@@ -273,7 +273,7 @@
   /**
    * @brief The local keychain to generate and install identities, keys and certificates
    */
-  security::KeyChain& m_keyChain;
+  ndn::KeyChain& m_keyChain;
   /**
    * @brief State about how identity/key is generated.
    */
@@ -282,11 +282,10 @@
   /**
    * @brief The keypair for the request.
    */
-  security::Key m_keyPair;
+  ndn::security::Key m_keyPair;
 };
 
 } // namespace requester
 } // namespace ndncert
-} // namespace ndn
 
 #endif // NDNCERT_REQUESTER_REQUEST_HPP