diff --git a/.waf-tools/default-compiler-flags.py b/.waf-tools/default-compiler-flags.py
index 629b8cf..bba2b1e 100644
--- a/.waf-tools/default-compiler-flags.py
+++ b/.waf-tools/default-compiler-flags.py
@@ -4,41 +4,63 @@
 
 def options(opt):
     opt.add_option('--debug', '--with-debug', action='store_true', default=False, dest='debug',
-                   help='''Compile in debugging mode without optimizations (-O0 or -Og)''')
+                   help='''Compile in debugging mode with minimal optimizations (-O0 or -Og)''')
 
 def configure(conf):
-    cxx = conf.env['CXX_NAME'] # CXX_NAME represents generic name of the compiler
-    if cxx == 'gcc':
-        flags = GccFlags()
-    elif cxx == 'clang':
-        flags = ClangFlags()
-    else:
-        flags = CompilerFlags()
-        Logs.warn('The code has not yet been tested with %s compiler' % cxx)
+    conf.start_msg('Checking C++ compiler version')
 
-    areCustomCxxflagsPresent = (len(conf.env.CXXFLAGS) > 0)
+    cxx = conf.env['CXX_NAME'] # CXX_NAME is the generic name of the compiler
+    ccver = tuple(int(i) for i in conf.env['CC_VERSION'])
+    errmsg = ''
+    warnmsg = ''
+    if cxx == 'gcc':
+        if ccver < (4, 8, 2):
+            errmsg = ('The version of gcc you are using is too old.\n'
+                      'The minimum supported gcc version is 4.8.2.')
+        conf.flags = GccFlags()
+    elif cxx == 'clang':
+        if ccver < (3, 4, 0):
+            errmsg = ('The version of clang you are using is too old.\n'
+                      'The minimum supported clang version is 3.4.0.')
+        conf.flags = ClangFlags()
+    else:
+        warnmsg = 'Note: %s compiler is unsupported' % cxx
+        conf.flags = CompilerFlags()
+
+    if errmsg:
+        conf.end_msg('.'.join(conf.env['CC_VERSION']), color='RED')
+        conf.fatal(errmsg)
+    elif warnmsg:
+        conf.end_msg('.'.join(conf.env['CC_VERSION']), color='YELLOW')
+        Logs.warn(warnmsg)
+    else:
+        conf.end_msg('.'.join(conf.env['CC_VERSION']))
+
+    conf.areCustomCxxflagsPresent = (len(conf.env.CXXFLAGS) > 0)
 
     # General flags are always applied (e.g., selecting C++11 mode)
-    generalFlags = flags.getGeneralFlags(conf)
+    generalFlags = conf.flags.getGeneralFlags(conf)
     conf.add_supported_cxxflags(generalFlags['CXXFLAGS'])
     conf.add_supported_linkflags(generalFlags['LINKFLAGS'])
     conf.env.DEFINES += generalFlags['DEFINES']
 
+@Configure.conf
+def check_compiler_flags(conf):
     # Debug or optimized CXXFLAGS and LINKFLAGS are applied only if the
     # corresponding environment variables are not set.
     # DEFINES are always applied.
     if conf.options.debug:
-        extraFlags = flags.getDebugFlags(conf)
-        if areCustomCxxflagsPresent:
+        extraFlags = conf.flags.getDebugFlags(conf)
+        if conf.areCustomCxxflagsPresent:
             missingFlags = [x for x in extraFlags['CXXFLAGS'] if x not in conf.env.CXXFLAGS]
             if len(missingFlags) > 0:
                 Logs.warn("Selected debug mode, but CXXFLAGS is set to a custom value '%s'"
                           % " ".join(conf.env.CXXFLAGS))
                 Logs.warn("Default flags '%s' are not activated" % " ".join(missingFlags))
     else:
-        extraFlags = flags.getOptimizedFlags(conf)
+        extraFlags = conf.flags.getOptimizedFlags(conf)
 
-    if not areCustomCxxflagsPresent:
+    if not conf.areCustomCxxflagsPresent:
         conf.add_supported_cxxflags(extraFlags['CXXFLAGS'])
         conf.add_supported_linkflags(extraFlags['LINKFLAGS'])
 
@@ -55,9 +77,10 @@
     self.start_msg('Checking supported CXXFLAGS')
 
     supportedFlags = []
-    for flag in cxxflags:
-        if self.check_cxx(cxxflags=['-Werror', flag], mandatory=False):
-            supportedFlags += [flag]
+    for flags in cxxflags:
+        flags = Utils.to_list(flags)
+        if self.check_cxx(cxxflags=['-Werror'] + flags, mandatory=False):
+            supportedFlags += flags
 
     self.end_msg(' '.join(supportedFlags))
     self.env.prepend_value('CXXFLAGS', supportedFlags)
@@ -73,9 +96,10 @@
     self.start_msg('Checking supported LINKFLAGS')
 
     supportedFlags = []
-    for flag in linkflags:
-        if self.check_cxx(linkflags=['-Werror', flag], mandatory=False):
-            supportedFlags += [flag]
+    for flags in linkflags:
+        flags = Utils.to_list(flags)
+        if self.check_cxx(linkflags=['-Werror'] + flags, mandatory=False):
+            supportedFlags += flags
 
     self.end_msg(' '.join(supportedFlags))
     self.env.prepend_value('LINKFLAGS', supportedFlags)
@@ -98,19 +122,26 @@
     """
     This class defines basic flags that work for both gcc and clang compilers
     """
+    def getGeneralFlags(self, conf):
+        flags = super(GccBasicFlags, self).getGeneralFlags(conf)
+        flags['CXXFLAGS'] += ['-std=c++11']
+        return flags
+
     def getDebugFlags(self, conf):
         flags = super(GccBasicFlags, self).getDebugFlags(conf)
         flags['CXXFLAGS'] += ['-O0',
+                              '-Og', # gcc >= 4.8, clang >= 4.0
                               '-g3',
                               '-pedantic',
                               '-Wall',
                               '-Wextra',
                               '-Werror',
-                              '-Wno-unused-parameter',
-                              '-Wno-error=maybe-uninitialized', # Bug #1615
+                              '-Wnon-virtual-dtor',
                               '-Wno-error=deprecated-declarations', # Bug #3795
-                              '-Wno-error=unused-local-typedefs',
+                              '-Wno-error=maybe-uninitialized', # Bug #1615
+                              '-Wno-unused-parameter',
                               ]
+        flags['LINKFLAGS'] += ['-fuse-ld=gold', '-Wl,-O1']
         return flags
 
     def getOptimizedFlags(self, conf):
@@ -120,30 +151,19 @@
                               '-pedantic',
                               '-Wall',
                               '-Wextra',
+                              '-Wnon-virtual-dtor',
                               '-Wno-unused-parameter',
                               ]
+        flags['LINKFLAGS'] += ['-fuse-ld=gold', '-Wl,-O1']
         return flags
 
 class GccFlags(GccBasicFlags):
-    def getGeneralFlags(self, conf):
-        flags = super(GccFlags, self).getGeneralFlags(conf)
-        version = tuple(int(i) for i in conf.env['CC_VERSION'])
-        if version < (4, 8, 2):
-            conf.fatal('The version of gcc you are using (%s) is too old.\n' %
-                       '.'.join(conf.env['CC_VERSION']) +
-                       'The minimum supported gcc version is 4.8.2.')
-        else:
-            flags['CXXFLAGS'] += ['-std=c++11']
-        return flags
-
     def getDebugFlags(self, conf):
         flags = super(GccFlags, self).getDebugFlags(conf)
         version = tuple(int(i) for i in conf.env['CC_VERSION'])
         if version < (5, 1, 0):
             flags['CXXFLAGS'] += ['-Wno-missing-field-initializers']
-        flags['CXXFLAGS'] += ['-Og', # gcc >= 4.8
-                              '-fdiagnostics-color', # gcc >= 4.9
-                              ]
+        flags['CXXFLAGS'] += ['-fdiagnostics-color'] # gcc >= 4.9
         return flags
 
     def getOptimizedFlags(self, conf):
@@ -157,26 +177,36 @@
 class ClangFlags(GccBasicFlags):
     def getGeneralFlags(self, conf):
         flags = super(ClangFlags, self).getGeneralFlags(conf)
-        flags['CXXFLAGS'] += ['-std=c++11']
-        if Utils.unversioned_sys_platform() == 'darwin':
-            flags['CXXFLAGS'] += ['-stdlib=libc++']
-            flags['LINKFLAGS'] += ['-stdlib=libc++']
+        version = tuple(int(i) for i in conf.env['CC_VERSION'])
+        if Utils.unversioned_sys_platform() == 'darwin' and version >= (9, 0, 0): # Bug #4296
+            flags['CXXFLAGS'] += [['-isystem', '/usr/local/include'], # for Homebrew
+                                  ['-isystem', '/opt/local/include']] # for MacPorts
         return flags
 
     def getDebugFlags(self, conf):
         flags = super(ClangFlags, self).getDebugFlags(conf)
         flags['CXXFLAGS'] += ['-fcolor-diagnostics',
-                              '-Wno-unused-local-typedef', # Bugs #2657 and #3209
-                              '-Wno-error=unneeded-internal-declaration', # Bug #1588
+                              '-Wextra-semi',
+                              '-Wundefined-func-template',
                               '-Wno-error=deprecated-register',
-                              '-Wno-error=keyword-macro', # Bug #3235
                               '-Wno-error=infinite-recursion', # Bug #3358
+                              '-Wno-error=keyword-macro', # Bug #3235
+                              '-Wno-error=unneeded-internal-declaration', # Bug #1588
+                              '-Wno-unused-local-typedef', # Bugs #2657 and #3209
                               ]
+        version = tuple(int(i) for i in conf.env['CC_VERSION'])
+        if version < (3, 9, 0) or (Utils.unversioned_sys_platform() == 'darwin' and version < (8, 1, 0)):
+            flags['CXXFLAGS'] += ['-Wno-unknown-pragmas']
         return flags
 
     def getOptimizedFlags(self, conf):
         flags = super(ClangFlags, self).getOptimizedFlags(conf)
         flags['CXXFLAGS'] += ['-fcolor-diagnostics',
+                              '-Wextra-semi',
+                              '-Wundefined-func-template',
                               '-Wno-unused-local-typedef', # Bugs #2657 and #3209
                               ]
+        version = tuple(int(i) for i in conf.env['CC_VERSION'])
+        if version < (3, 9, 0) or (Utils.unversioned_sys_platform() == 'darwin' and version < (8, 1, 0)):
+            flags['CXXFLAGS'] += ['-Wno-unknown-pragmas']
         return flags
diff --git a/src/ca-storage.cpp b/src/ca-storage.cpp
index 3f8aeb5..ebe5c98 100644
--- a/src/ca-storage.cpp
+++ b/src/ca-storage.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /**
- * Copyright (c) 2017, Regents of the University of California.
+ * Copyright (c) 2017-2018, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -23,6 +23,8 @@
 namespace ndn {
 namespace ndncert {
 
+CaStorage::~CaStorage() = default;
+
 unique_ptr<CaStorage>
 CaStorage::createCaStorage(const std::string& caStorageType)
 {
diff --git a/src/ca-storage.hpp b/src/ca-storage.hpp
index 0a85f6c..ab5e38d 100644
--- a/src/ca-storage.hpp
+++ b/src/ca-storage.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /**
- * Copyright (c) 2017, Regents of the University of California.
+ * Copyright (c) 2017-2018, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -38,8 +38,10 @@
     using std::runtime_error::runtime_error;
   };
 
-public:
-  // certificate request related
+  virtual
+  ~CaStorage();
+
+public: // certificate request related
   virtual CertificateRequest
   getRequest(const std::string& requestId) = 0;
 
@@ -58,7 +60,7 @@
   virtual std::list<CertificateRequest>
   listAllRequests(const Name& caName) = 0;
 
-  // certificate related
+public: // certificate related
   virtual security::v2::Certificate
   getCertificate(const std::string& certId) = 0;
 
@@ -77,7 +79,7 @@
   virtual std::list<security::v2::Certificate>
   listAllIssuedCertificates(const Name& caName) = 0;
 
-public:
+public: // factory
   template<class CaStorageType>
   static void
   registerCaStorage(const std::string& caStorageType = CaStorageType::STORAGE_TYPE)
diff --git a/src/challenge-module.cpp b/src/challenge-module.cpp
index 224a30c..c1f3432 100644
--- a/src/challenge-module.cpp
+++ b/src/challenge-module.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /**
- * Copyright (c) 2017, Regents of the University of California.
+ * Copyright (c) 2017-2018, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -37,6 +37,8 @@
 {
 }
 
+ChallengeModule::~ChallengeModule() = default;
+
 unique_ptr<ChallengeModule>
 ChallengeModule::createChallengeModule(const std::string& canonicalName)
 {
diff --git a/src/challenge-module.hpp b/src/challenge-module.hpp
index af0d40b..b2d39ad 100644
--- a/src/challenge-module.hpp
+++ b/src/challenge-module.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /**
- * Copyright (c) 2017, Regents of the University of California.
+ * Copyright (c) 2017-2018, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -44,8 +44,12 @@
   };
 
 public:
+  explicit
   ChallengeModule(const std::string& uniqueType);
 
+  virtual
+  ~ChallengeModule();
+
   template<class ChallengeType>
   static void
   registerChallengeModule(const std::string& typeName)
diff --git a/src/client-module.cpp b/src/client-module.cpp
index e4162d2..0d98d90 100644
--- a/src/client-module.cpp
+++ b/src/client-module.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /**
- * Copyright (c) 2017, Regents of the University of California.
+ * Copyright (c) 2017-2018, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -38,6 +38,8 @@
 {
 }
 
+ClientModule::~ClientModule() = default;
+
 void
 ClientModule::requestCaTrustAnchor(const Name& caName, const DataCallback& trustAnchorCallback,
                                    const ErrorCallback& errorCallback)
diff --git a/src/client-module.hpp b/src/client-module.hpp
index e285ce2..df2a43a 100644
--- a/src/client-module.hpp
+++ b/src/client-module.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /**
- * Copyright (c) 2017, Regents of the University of California.
+ * Copyright (c) 2017-2018, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -64,9 +64,11 @@
   using ErrorCallback = function<void (const std::string&)>;
 
 public:
-  explicit
   ClientModule(Face& face, security::v2::KeyChain& keyChain, size_t retryTimes = 2);
 
+  virtual
+  ~ClientModule();
+
   ClientConfig&
   getClientConf()
   {
@@ -176,7 +178,6 @@
   virtual void
   onNack(const Interest& interest, const lp::Nack& nack, const ErrorCallback& errorCallback);
 
-
 protected:
   ClientConfig m_config;
   Face& m_face;
diff --git a/wscript b/wscript
index 438b03f..8cb55dc 100644
--- a/wscript
+++ b/wscript
@@ -1,8 +1,8 @@
 # -*- Mode: python; py-indent-offset: 4; indent-tabs-mode: nil; coding: utf-8; -*-
 VERSION = "0.1.0"
 APPNAME = "ndncert"
-BUGREPORT = "http://redmine.named-data.net/projects/ndncert"
-GIT_TAG_PREFIX = "ndncert"
+BUGREPORT = "https://redmine.named-data.net/projects/ndncert"
+GIT_TAG_PREFIX = "ndncert-"
 
 from waflib import Logs, Utils, Context
 import os
@@ -11,11 +11,12 @@
     opt.load(['compiler_cxx', 'gnu_dirs'])
     opt.load(['boost', 'default-compiler-flags', 'sqlite3',
               'coverage', 'sanitizers',
-              'doxygen', 'sphinx_build'], tooldir=['.waf-tools'])
+              'doxygen', 'sphinx_build'],
+             tooldir=['.waf-tools'])
 
-    syncopt = opt.add_option_group ("ndncert options")
-    syncopt.add_option('--with-tests', action='store_true', default=False, dest='with_tests',
-                       help='''build unit tests''')
+    certopt = opt.add_option_group("ndncert options")
+    certopt.add_option('--with-tests', action='store_true', default=False, dest='with_tests',
+                       help='''Build unit tests''')
 
 def configure(conf):
     conf.load(['compiler_cxx', 'gnu_dirs',
@@ -23,8 +24,7 @@
                'doxygen', 'sphinx_build'])
 
     if 'PKG_CONFIG_PATH' not in os.environ:
-       os.environ['PKG_CONFIG_PATH'] = Utils.subst_vars('${LIBDIR}/pkgconfig', conf.env)
-
+        os.environ['PKG_CONFIG_PATH'] = Utils.subst_vars('${LIBDIR}/pkgconfig', conf.env)
     conf.check_cfg(package='libndn-cxx', args=['--cflags', '--libs'],
                    uselib_store='NDN_CXX', mandatory=True)
 
@@ -40,10 +40,12 @@
     if conf.env.BOOST_VERSION_NUMBER < 105400:
         Logs.error("Minimum required boost version is 1.54.0")
         Logs.error("Please upgrade your distribution or install custom boost libraries" +
-                    " (https://redmine.named-data.net/projects/nfd/wiki/Boost_FAQ)")
+                   " (https://redmine.named-data.net/projects/nfd/wiki/Boost_FAQ)")
         return
 
-    # Loading "late" to prevent tests to be compiled with profiling flags
+    conf.check_compiler_flags()
+
+    # Loading "late" to prevent tests from being compiled with profiling flags
     conf.load('coverage')
 
     conf.load('sanitizers')
@@ -70,7 +72,6 @@
     )
 
     bld.recurse('tools')
-
     bld.recurse('tests')
 
     bld.install_files(
@@ -88,9 +89,7 @@
         )
 
     bld.install_files("${SYSCONFDIR}/ndncert", "ca.conf.sample")
-
     bld.install_files("${SYSCONFDIR}/ndncert", "client.conf.sample")
-
     bld.install_files("${SYSCONFDIR}/ndncert", "ndncert-mail.conf.sample")
 
     bld(features="subst",