diff --git a/src/AbstractAuthResolver.cc b/src/AbstractAuthResolver.cc
index a9730f3d..9eceeba4 100644
--- a/src/AbstractAuthResolver.cc
+++ b/src/AbstractAuthResolver.cc
@@ -34,6 +34,7 @@
 /* copyright --> */
 #include "AbstractAuthResolver.h"
 #include "AuthConfig.h"
+#include "a2functional.h"
 
 namespace aria2 {
 
@@ -41,16 +42,29 @@ AbstractAuthResolver::AbstractAuthResolver() {}
 
 AbstractAuthResolver::~AbstractAuthResolver() {}
 
-void AbstractAuthResolver::setUserDefinedAuthConfig
-(const std::shared_ptr<AuthConfig>& authConfig)
+void AbstractAuthResolver::setUserDefinedCred
+(std::string user, std::string password)
 {
-  userDefinedAuthConfig_ = authConfig;
+  userDefinedUser_ = std::move(user);
+  userDefinedPassword_ = std::move(password);
 }
 
-void AbstractAuthResolver::setDefaultAuthConfig
-(const std::shared_ptr<AuthConfig>& authConfig)
+std::unique_ptr<AuthConfig>
+AbstractAuthResolver::getUserDefinedAuthConfig() const
 {
-  defaultAuthConfig_ = authConfig;
+  return AuthConfig::create(userDefinedUser_, userDefinedPassword_);
+}
+
+void AbstractAuthResolver::setDefaultCred
+(std::string user, std::string password)
+{
+  defaultUser_ = std::move(user);
+  defaultPassword_ = std::move(password);
+}
+
+std::unique_ptr<AuthConfig> AbstractAuthResolver::getDefaultAuthConfig() const
+{
+  return AuthConfig::create(defaultUser_, defaultPassword_);
 }
 
 } // namespace aria2
diff --git a/src/AbstractAuthResolver.h b/src/AbstractAuthResolver.h
index 4801490f..25dd923e 100644
--- a/src/AbstractAuthResolver.h
+++ b/src/AbstractAuthResolver.h
@@ -40,29 +40,24 @@
 namespace aria2 {
 
 class AbstractAuthResolver : public AuthResolver {
-private:
-  std::shared_ptr<AuthConfig> userDefinedAuthConfig_;
-
-  std::shared_ptr<AuthConfig> defaultAuthConfig_;
 public:
   AbstractAuthResolver();
 
   virtual ~AbstractAuthResolver();
 
-  void setUserDefinedAuthConfig(const std::shared_ptr<AuthConfig>& authConfig);
+  void setUserDefinedCred(std::string user, std::string password);
 
-  const std::shared_ptr<AuthConfig>& getUserDefinedAuthConfig() const
-  {
-    return userDefinedAuthConfig_;
-  }
+  std::unique_ptr<AuthConfig> getUserDefinedAuthConfig() const;
 
-  void setDefaultAuthConfig(const std::shared_ptr<AuthConfig>& authConfig);
+  void setDefaultCred(std::string user, std::string password);
 
-  const std::shared_ptr<AuthConfig>& getDefaultAuthConfig() const
-  {
-    return defaultAuthConfig_;
-  }
+  std::unique_ptr<AuthConfig> getDefaultAuthConfig() const;
+private:
+  std::string userDefinedUser_;
+  std::string userDefinedPassword_;
 
+  std::string defaultUser_;
+  std::string defaultPassword_;
 };
 
 } // namespace aria2
diff --git a/src/AuthConfig.cc b/src/AuthConfig.cc
index ed9c465f..379eb6f8 100644
--- a/src/AuthConfig.cc
+++ b/src/AuthConfig.cc
@@ -42,9 +42,9 @@ namespace aria2 {
 
 AuthConfig::AuthConfig() {}
 
-AuthConfig::AuthConfig(const std::string& user, const std::string& password)
-    : user_(user),
-      password_(password)
+AuthConfig::AuthConfig(std::string user, std::string password)
+  : user_(std::move(user)),
+    password_(std::move(password))
 {}
 
 AuthConfig::~AuthConfig() {}
@@ -57,6 +57,16 @@ std::string AuthConfig::getAuthText() const
   return s;
 }
 
+std::unique_ptr<AuthConfig> AuthConfig::create
+(std::string user, std::string password)
+{
+  if(user.empty()) {
+    return std::unique_ptr<AuthConfig>();
+  } else {
+    return make_unique<AuthConfig>(std::move(user), std::move(password));
+  }
+}
+
 std::ostream& operator<<(std::ostream& o,
                          const std::shared_ptr<AuthConfig>& authConfig)
 {
diff --git a/src/AuthConfig.h b/src/AuthConfig.h
index cae54a40..e25c0af3 100644
--- a/src/AuthConfig.h
+++ b/src/AuthConfig.h
@@ -50,7 +50,7 @@ private:
   std::string password_;
 public:
   AuthConfig();
-  AuthConfig(const std::string& user, const std::string& password);
+  AuthConfig(std::string user, std::string password);
   ~AuthConfig();
 
   // Don't allow copying
@@ -68,6 +68,9 @@ public:
   {
     return password_;
   }
+
+  static std::unique_ptr<AuthConfig> create
+  (std::string user, std::string password);
 };
 
 std::ostream& operator<<(std::ostream& o,
diff --git a/src/AuthConfigFactory.cc b/src/AuthConfigFactory.cc
index 802ad367..784e9ba4 100644
--- a/src/AuthConfigFactory.cc
+++ b/src/AuthConfigFactory.cc
@@ -56,33 +56,32 @@ AuthConfigFactory::AuthConfigFactory() {}
 
 AuthConfigFactory::~AuthConfigFactory() {}
 
-std::shared_ptr<AuthConfig>
+std::unique_ptr<AuthConfig>
 AuthConfigFactory::createAuthConfig
 (const std::shared_ptr<Request>& request, const Option* op)
 {
   if(request->getProtocol() == "http" || request->getProtocol() == "https") {
-
     if(op->getAsBool(PREF_HTTP_AUTH_CHALLENGE)) {
       if(!request->getUsername().empty()) {
-        std::shared_ptr<BasicCred> bc(new BasicCred(request->getUsername(),
-                                                 request->getPassword(),
-                                                 request->getHost(),
-                                                 request->getPort(),
-                                                 request->getDir(), true));
-        updateBasicCred(bc);
-        return createAuthConfig(request->getUsername(), request->getPassword());
+        updateBasicCred(make_unique<BasicCred>(request->getUsername(),
+                                               request->getPassword(),
+                                               request->getHost(),
+                                               request->getPort(),
+                                               request->getDir(), true));
+        return AuthConfig::create(request->getUsername(),
+                                  request->getPassword());
       }
-      BasicCredSet::iterator i =
-        findBasicCred(request->getHost(), request->getPort(),
-                      request->getDir());
-      if(i == basicCreds_.end()) {
-        return std::shared_ptr<AuthConfig>();
+      auto i = findBasicCred(request->getHost(), request->getPort(),
+                             request->getDir());
+      if(i == std::end(basicCreds_)) {
+        return std::unique_ptr<AuthConfig>();
       } else {
-        return createAuthConfig((*i)->user_, (*i)->password_);
+        return AuthConfig::create((*i)->user_, (*i)->password_);
       }
     } else {
       if(!request->getUsername().empty()) {
-        return createAuthConfig(request->getUsername(), request->getPassword());
+        return AuthConfig::create(request->getUsername(),
+                                  request->getPassword());
       } else {
         return
           createHttpAuthResolver(op)->resolveAuthConfig(request->getHost());
@@ -91,93 +90,80 @@ AuthConfigFactory::createAuthConfig
   } else if(request->getProtocol() == "ftp") {
     if(!request->getUsername().empty()) {
       if(request->hasPassword()) {
-        return createAuthConfig(request->getUsername(), request->getPassword());
+        return AuthConfig::create(request->getUsername(),
+                                  request->getPassword());
       } else {
         if(!op->getAsBool(PREF_NO_NETRC)) {
           // First, check we have password corresponding to host and
           // username
           NetrcAuthResolver authResolver;
-          authResolver.setNetrc(netrc_);
+          authResolver.setNetrc(netrc_.get());
 
-          std::shared_ptr<AuthConfig> ac =
-            authResolver.resolveAuthConfig(request->getHost());
+          auto ac = authResolver.resolveAuthConfig(request->getHost());
           if(ac && ac->getUser() == request->getUsername()) {
             return ac;
           }
         }
         // We don't have password for host and username. Return
         // password specified by --ftp-passwd
-        return
-          createAuthConfig(request->getUsername(), op->get(PREF_FTP_PASSWD));
+        return AuthConfig::create(request->getUsername(),
+                                  op->get(PREF_FTP_PASSWD));
       }
     } else {
       return
         createFtpAuthResolver(op)->resolveAuthConfig(request->getHost());
     }
   } else {
-    return std::shared_ptr<AuthConfig>();
+    return std::unique_ptr<AuthConfig>();
   }
 }
 
-std::shared_ptr<AuthConfig>
-AuthConfigFactory::createAuthConfig(const std::string& user, const std::string& password) const
-{
-  std::shared_ptr<AuthConfig> ac;
-  if(!user.empty()) {
-    ac.reset(new AuthConfig(user, password));
-  }
-  return ac;
-}
-
-std::shared_ptr<AuthResolver> AuthConfigFactory::createHttpAuthResolver
+std::unique_ptr<AuthResolver> AuthConfigFactory::createHttpAuthResolver
 (const Option* op) const
 {
-  AbstractAuthResolver* resolver;
+  std::unique_ptr<AbstractAuthResolver> resolver;
   if(op->getAsBool(PREF_NO_NETRC)) {
-    resolver = new DefaultAuthResolver();
+    resolver.reset(new DefaultAuthResolver());
   } else {
-    NetrcAuthResolver* authResolver(new NetrcAuthResolver());
-    authResolver->setNetrc(netrc_);
+    auto authResolver = make_unique<NetrcAuthResolver>();
+    authResolver->setNetrc(netrc_.get());
     authResolver->ignoreDefault();
-    resolver = authResolver;
+    resolver = std::move(authResolver);
   }
-  resolver->setUserDefinedAuthConfig
-    (createAuthConfig(op->get(PREF_HTTP_USER), op->get(PREF_HTTP_PASSWD)));
-  return std::shared_ptr<AuthResolver>(resolver);
+  resolver->setUserDefinedCred(op->get(PREF_HTTP_USER),
+                               op->get(PREF_HTTP_PASSWD));
+  return std::move(resolver);
 }
 
-std::shared_ptr<AuthResolver> AuthConfigFactory::createFtpAuthResolver
+std::unique_ptr<AuthResolver> AuthConfigFactory::createFtpAuthResolver
 (const Option* op) const
 {
-  AbstractAuthResolver* resolver;
+  std::unique_ptr<AbstractAuthResolver> resolver;
   if(op->getAsBool(PREF_NO_NETRC)) {
-    resolver = new DefaultAuthResolver();
+    resolver.reset(new DefaultAuthResolver());
   } else {
-    NetrcAuthResolver* authResolver(new NetrcAuthResolver());
-    authResolver->setNetrc(netrc_);
-    resolver = authResolver;
+    auto authResolver = make_unique<NetrcAuthResolver>();
+    authResolver->setNetrc(netrc_.get());
+    resolver = std::move(authResolver);
   }
-  resolver->setUserDefinedAuthConfig
-    (createAuthConfig(op->get(PREF_FTP_USER), op->get(PREF_FTP_PASSWD)));
-  std::shared_ptr<AuthConfig> defaultAuthConfig
-    (new AuthConfig(AUTH_DEFAULT_USER, AUTH_DEFAULT_PASSWD));
-  resolver->setDefaultAuthConfig(defaultAuthConfig);
-  return std::shared_ptr<AuthResolver>(resolver);
+  resolver->setUserDefinedCred(op->get(PREF_FTP_USER),
+                               op->get(PREF_FTP_PASSWD));
+  resolver->setDefaultCred(AUTH_DEFAULT_USER, AUTH_DEFAULT_PASSWD);
+  return std::move(resolver);
 }
 
-void AuthConfigFactory::setNetrc(const std::shared_ptr<Netrc>& netrc)
+void AuthConfigFactory::setNetrc(std::unique_ptr<Netrc> netrc)
 {
-  netrc_ = netrc;
+  netrc_ = std::move(netrc);
 }
 
-void AuthConfigFactory::updateBasicCred
-(const std::shared_ptr<BasicCred>& basicCred)
+void AuthConfigFactory::updateBasicCred(std::unique_ptr<BasicCred> basicCred)
 {
-  BasicCredSet::iterator i = basicCreds_.lower_bound(basicCred);
-  if(i != basicCreds_.end() && *(*i) == *basicCred) {
-    *(*i) = *basicCred;
+  auto i = basicCreds_.lower_bound(basicCred);
+  if(i != std::end(basicCreds_) && *i == basicCred) {
+    *(*i) = std::move(*basicCred);
   } else {
-    basicCreds_.insert(i, basicCred);
+    basicCreds_.insert(i, std::move(basicCred));
   }
 }
 
@@ -187,17 +173,15 @@ bool AuthConfigFactory::activateBasicCred
  const std::string& path,
  const Option* op)
 {
-  BasicCredSet::iterator i = findBasicCred(host, port, path);
-  if(i == basicCreds_.end()) {
-    std::shared_ptr<AuthConfig> authConfig =
-      createHttpAuthResolver(op)->resolveAuthConfig(host);
+  auto i = findBasicCred(host, port, path);
+  if(i == std::end(basicCreds_)) {
+    auto authConfig = createHttpAuthResolver(op)->resolveAuthConfig(host);
     if(!authConfig) {
       return false;
     } else {
-      std::shared_ptr<BasicCred> bc
-        (new BasicCred(authConfig->getUser(), authConfig->getPassword(),
-                       host, port, path, true));
-      basicCreds_.insert(bc);
+      basicCreds_.insert(make_unique<BasicCred>(authConfig->getUser(),
+                                                authConfig->getPassword(),
+                                                host, port, path, true));
       return true;
     }
   } else {
@@ -206,55 +190,59 @@ bool AuthConfigFactory::activateBasicCred
   }
 }
 
-AuthConfigFactory::BasicCred::BasicCred
-(const std::string& user, const std::string& password,
- const std::string& host, uint16_t port, const std::string& path,
- bool activated):
-  user_(user), password_(password),
-  host_(host), port_(port), path_(path), activated_(activated)
+BasicCred::BasicCred
+(std::string user, std::string password,
+ std::string host, uint16_t port, std::string path,
+ bool activated)
+  : user_(std::move(user)),
+    password_(std::move(password)),
+    host_(std::move(host)),
+    port_(port),
+    path_(std::move(path)),
+    activated_(activated)
 {
   if(path_.empty() || path_[path_.size()-1] != '/') {
     path_ += "/";
   }
 }
 
-void AuthConfigFactory::BasicCred::activate()
+void BasicCred::activate()
 {
   activated_ = true;
 }
 
-bool AuthConfigFactory::BasicCred::isActivated() const
+bool BasicCred::isActivated() const
 {
   return activated_;
 }
 
-bool AuthConfigFactory::BasicCred::operator==(const BasicCred& cred) const
+bool BasicCred::operator==(const BasicCred& cred) const
 {
   return host_ == cred.host_ && port_ == cred.port_ && path_ == cred.path_;
 }
 
-bool AuthConfigFactory::BasicCred::operator<(const BasicCred& cred) const
+bool BasicCred::operator<(const BasicCred& cred) const
 {
   return host_ < cred.host_ ||
     (!(cred.host_ < host_) && (port_ < cred.port_ ||
                                (!(cred.port_ < port_) && path_ > cred.path_)));
 }
 
-AuthConfigFactory::BasicCredSet::iterator
-AuthConfigFactory::findBasicCred
+AuthConfigFactory::BasicCredSet::iterator AuthConfigFactory::findBasicCred
 (const std::string& host,
  uint16_t port,
  const std::string& path)
 {
-  std::shared_ptr<BasicCred> bc(new BasicCred("", "", host, port, path));
-  BasicCredSet::iterator i = basicCreds_.lower_bound(bc);
-  for(; i != basicCreds_.end() && (*i)->host_ == host && (*i)->port_ == port;
-      ++i) {
+  auto bc = make_unique<BasicCred>("", "", host, port, path);
+  auto i = basicCreds_.lower_bound(bc);
+  for(; i != std::end(basicCreds_) &&
+        (*i)->host_ == host &&
+        (*i)->port_ == port; ++i) {
     if(util::startsWith(bc->path_, (*i)->path_)) {
       return i;
     }
   }
-  return basicCreds_.end();
+  return std::end(basicCreds_);
 }
 
 } // namespace aria2
diff --git a/src/AuthConfigFactory.h b/src/AuthConfigFactory.h
index e863db6d..03c85bd4 100644
--- a/src/AuthConfigFactory.h
+++ b/src/AuthConfigFactory.h
@@ -52,42 +52,39 @@ class AuthConfig;
 class Request;
 class AuthResolver;
 
-class AuthConfigFactory {
-private:
-  std::shared_ptr<Netrc> netrc_;
-
-  std::shared_ptr<AuthConfig> createAuthConfig(const std::string& user,
-                                            const std::string& password) const;
-
-  std::shared_ptr<AuthResolver> createHttpAuthResolver(const Option* op) const;
-
-  std::shared_ptr<AuthResolver> createFtpAuthResolver(const Option* op) const;
+class BasicCred {
 public:
-  class BasicCred {
-  public:
-    std::string user_;
-    std::string password_;
-    std::string host_;
-    uint16_t port_;
-    std::string path_;
-    bool activated_;
+  std::string user_;
+  std::string password_;
+  std::string host_;
+  uint16_t port_;
+  std::string path_;
+  bool activated_;
 
-    BasicCred(const std::string& user, const std::string& password,
-              const std::string& host, uint16_t port, const std::string& path,
-              bool activated = false);
+  BasicCred(std::string user, std::string password,
+            std::string host, uint16_t port, std::string path,
+            bool activated = false);
 
-    void activate();
+  void activate();
 
-    bool isActivated() const;
+  bool isActivated() const;
 
-    bool operator==(const BasicCred& cred) const;
+  bool operator==(const BasicCred& cred) const;
 
-    bool operator<(const BasicCred& cred) const;
-  };
+  bool operator<(const BasicCred& cred) const;
+};
 
-  typedef std::set<std::shared_ptr<BasicCred>,
-                   DerefLess<std::shared_ptr<BasicCred> > > BasicCredSet;
+class AuthConfigFactory {
+public:
+  typedef std::set<std::unique_ptr<BasicCred>,
+                   DerefLess<std::unique_ptr<BasicCred>>> BasicCredSet;
 private:
+  std::unique_ptr<Netrc> netrc_;
+
+  std::unique_ptr<AuthResolver> createHttpAuthResolver(const Option* op) const;
+
+  std::unique_ptr<AuthResolver> createFtpAuthResolver(const Option* op) const;
+
   BasicCredSet basicCreds_;
 public:
   AuthConfigFactory();
@@ -98,10 +95,10 @@ public:
   // are used in this method: PREF_HTTP_USER, PREF_HTTP_PASSWD,
   // PREF_FTP_USER, PREF_FTP_PASSWD, PREF_NO_NETRC and
   // PREF_HTTP_AUTH_CHALLENGE.
-  std::shared_ptr<AuthConfig> createAuthConfig
+  std::unique_ptr<AuthConfig> createAuthConfig
   (const std::shared_ptr<Request>& request, const Option* op);
 
-  void setNetrc(const std::shared_ptr<Netrc>& netrc);
+  void setNetrc(std::unique_ptr<Netrc> netrc);
 
   // Find a BasicCred using findBasicCred() and activate it then
   // return true.  If matching BasicCred is not found, AuthConfig
@@ -127,7 +124,9 @@ public:
   // If the same BasicCred is already added, then it is replaced with
   // given basicCred. Otherwise, insert given basicCred to
   // basicCreds_.
-  void updateBasicCred(const std::shared_ptr<BasicCred>& basicCred);
+  //
+  // Made public for unit test.
+  void updateBasicCred(std::unique_ptr<BasicCred> basicCred);
 };
 
 } // namespace aria2
diff --git a/src/AuthResolver.h b/src/AuthResolver.h
index e3b83449..c02e5ec5 100644
--- a/src/AuthResolver.h
+++ b/src/AuthResolver.h
@@ -48,7 +48,8 @@ class AuthResolver {
 public:
   virtual ~AuthResolver() {}
 
-  virtual std::shared_ptr<AuthConfig> resolveAuthConfig(const std::string& hostname) = 0;
+  virtual std::unique_ptr<AuthConfig> resolveAuthConfig
+  (const std::string& hostname) = 0;
 };
 
 } // namespace aria2
diff --git a/src/DefaultAuthResolver.cc b/src/DefaultAuthResolver.cc
index 2cb589cf..35357f8e 100644
--- a/src/DefaultAuthResolver.cc
+++ b/src/DefaultAuthResolver.cc
@@ -37,13 +37,14 @@
 
 namespace aria2 {
 
-std::shared_ptr<AuthConfig> DefaultAuthResolver::resolveAuthConfig
+std::unique_ptr<AuthConfig> DefaultAuthResolver::resolveAuthConfig
 (const std::string& hostname)
 {
-  if(!getUserDefinedAuthConfig()) {
-    return getDefaultAuthConfig();
+  auto authConfig = getUserDefinedAuthConfig();
+  if(authConfig) {
+    return authConfig;
   } else {
-    return getUserDefinedAuthConfig();
+    return getDefaultAuthConfig();
   }
 }
 
diff --git a/src/DefaultAuthResolver.h b/src/DefaultAuthResolver.h
index e3ddf509..ea2bcf61 100644
--- a/src/DefaultAuthResolver.h
+++ b/src/DefaultAuthResolver.h
@@ -41,7 +41,7 @@ namespace aria2 {
 
 class DefaultAuthResolver : public AbstractAuthResolver {
 public:
-  virtual std::shared_ptr<AuthConfig> resolveAuthConfig
+  virtual std::unique_ptr<AuthConfig> resolveAuthConfig
   (const std::string& hostname);
 };
 
diff --git a/src/MultiUrlRequestInfo.cc b/src/MultiUrlRequestInfo.cc
index 107d3ce0..8517b045 100644
--- a/src/MultiUrlRequestInfo.cc
+++ b/src/MultiUrlRequestInfo.cc
@@ -200,9 +200,9 @@ int MultiUrlRequestInfo::prepare()
         A2_LOG_NOTICE(fmt(MSG_INCORRECT_NETRC_PERMISSION,
                           option_->get(PREF_NETRC_PATH).c_str()));
       } else {
-        std::shared_ptr<Netrc> netrc(new Netrc());
+        auto netrc = make_unique<Netrc>();
         netrc->parse(option_->get(PREF_NETRC_PATH));
-        authConfigFactory->setNetrc(netrc);
+        authConfigFactory->setNetrc(std::move(netrc));
       }
     }
     e_->setAuthConfigFactory(std::move(authConfigFactory));
diff --git a/src/Netrc.cc b/src/Netrc.cc
index 0c7743d5..fc7b3aaa 100644
--- a/src/Netrc.cc
+++ b/src/Netrc.cc
@@ -50,14 +50,14 @@ namespace aria2 {
 Authenticator::Authenticator() {}
 
 Authenticator::Authenticator
-(const std::string& machine,
- const std::string& login,
- const std::string& password,
- const std::string& account)
-  : machine_(machine),
-    login_(login),
-    password_(password),
-    account_(account)
+(std::string machine,
+ std::string login,
+ std::string password,
+ std::string account)
+  : machine_(std::move(machine)),
+    login_(std::move(login)),
+    password_(std::move(password)),
+    account_(std::move(account))
 {}
 
 Authenticator::~Authenticator() {}
@@ -67,33 +67,34 @@ bool Authenticator::match(const std::string& hostname) const
   return util::noProxyDomainMatch(hostname, machine_);
 }
 
-void Authenticator::setMachine(const std::string& machine)
+void Authenticator::setMachine(std::string machine)
 {
-  machine_ = machine;
+  machine_ = std::move(machine);
 }
 
-void Authenticator::setLogin(const std::string& login)
+void Authenticator::setLogin(std::string login)
 {
-  login_ = login;
+  login_ = std::move(login);
 }
 
-void Authenticator::setPassword(const std::string& password)
+void Authenticator::setPassword(std::string password)
 {
-  password_ = password;
+  password_ = std::move(password);
 }
 
-void Authenticator::setAccount(const std::string& account)
+void Authenticator::setAccount(std::string account)
 {
-  account_ = account;
+  account_ = std::move(account);
 }
 
 DefaultAuthenticator::DefaultAuthenticator() {}
 
 DefaultAuthenticator::DefaultAuthenticator
-(const std::string& login,
- const std::string& password,
- const std::string& account)
-  : Authenticator(A2STR::NIL, login, password, account)
+(std::string login,
+ std::string password,
+ std::string account)
+  : Authenticator("", std::move(login), std::move(password),
+                  std::move(account))
 {}
 
 DefaultAuthenticator::~DefaultAuthenticator() {}
@@ -107,9 +108,9 @@ Netrc::Netrc() {}
 
 Netrc::~Netrc() {}
 
-void Netrc::addAuthenticator(const std::shared_ptr<Authenticator>& authenticator)
+void Netrc::addAuthenticator(std::unique_ptr<Authenticator> authenticator)
 {
-  authenticators_.push_back(authenticator);
+  authenticators_.push_back(std::move(authenticator));
 }
 
 namespace {
@@ -146,7 +147,7 @@ void Netrc::parse(const std::string& path)
     SET_ACCOUNT,
     SET_MACDEF
   };
-  std::shared_ptr<Authenticator> authenticator;
+  std::unique_ptr<Authenticator> authenticator;
   STATE state = GET_TOKEN;
   while(1) {
     std::string line = fp.getLine();
@@ -169,11 +170,11 @@ void Netrc::parse(const std::string& path)
           eoi = tokens.end(); iter != eoi; ++iter) {
       if(state == GET_TOKEN) {
         if(util::streq((*iter).first, (*iter).second, "machine")) {
-          storeAuthenticator(authenticator);
+          storeAuthenticator(std::move(authenticator));
           authenticator.reset(new Authenticator());
           state = SET_MACHINE;
         } else if(util::streq((*iter).first, (*iter).second, "default")) {
-          storeAuthenticator(authenticator);
+          storeAuthenticator(std::move(authenticator));
           authenticator.reset(new DefaultAuthenticator());
         } else {
           if(!authenticator) {
@@ -194,13 +195,13 @@ void Netrc::parse(const std::string& path)
         }
       } else {
         if(state == SET_MACHINE) {
-          authenticator->setMachine((*iter).first, (*iter).second);
+          authenticator->setMachine({(*iter).first, (*iter).second});
         } else if(state == SET_LOGIN) {
-          authenticator->setLogin((*iter).first, (*iter).second);
+          authenticator->setLogin({(*iter).first, (*iter).second});
         } else if(state == SET_PASSWORD) {
-          authenticator->setPassword((*iter).first, (*iter).second);
+          authenticator->setPassword({(*iter).first, (*iter).second});
         } else if(state == SET_ACCOUNT) {
-          authenticator->setAccount((*iter).first, (*iter).second);
+          authenticator->setAccount({(*iter).first, (*iter).second});
         } else if(state == SET_MACDEF) {
           skipMacdef(fp);
         }
@@ -212,13 +213,13 @@ void Netrc::parse(const std::string& path)
     throw DL_ABORT_EX
       ("Netrc:parse error. EOF reached where a token expected.");
   }
-  storeAuthenticator(authenticator);
+  storeAuthenticator(std::move(authenticator));
 }
 
-void Netrc::storeAuthenticator(const std::shared_ptr<Authenticator>& authenticator)
+void Netrc::storeAuthenticator(std::unique_ptr<Authenticator> authenticator)
 {
   if(authenticator) {
-    authenticators_.push_back(authenticator);
+    authenticators_.push_back(std::move(authenticator));
   }
 }
 
@@ -229,24 +230,31 @@ private:
 public:
   AuthHostMatch(const std::string& hostname):hostname(hostname) {}
 
-  bool operator()(const std::shared_ptr<Authenticator>& authenticator)
+  bool operator()(const std::unique_ptr<Authenticator>& authenticator)
   {
     return authenticator->match(hostname);
   }
 };
 } // namespace
 
-std::shared_ptr<Authenticator>
+const Authenticator*
 Netrc::findAuthenticator(const std::string& hostname) const
 {
-  std::shared_ptr<Authenticator> res;
-  std::vector<std::shared_ptr<Authenticator> >::const_iterator itr =
-    std::find_if(authenticators_.begin(), authenticators_.end(),
-                 AuthHostMatch(hostname));
-  if(itr != authenticators_.end()) {
-    res = *itr;
+  std::unique_ptr<Authenticator> res;
+  auto itr = std::find_if(std::begin(authenticators_),
+                          std::end(authenticators_),
+                          AuthHostMatch(hostname));
+  if(itr == std::end(authenticators_)) {
+    return nullptr;
+  } else {
+    return (*itr).get();
   }
-  return res;
+}
+
+const std::vector<std::unique_ptr<Authenticator>>&
+Netrc::getAuthenticators() const
+{
+  return authenticators_;
 }
 
 } // namespace aria2
diff --git a/src/Netrc.h b/src/Netrc.h
index 1fd25b27..a2845f78 100644
--- a/src/Netrc.h
+++ b/src/Netrc.h
@@ -59,10 +59,10 @@ private:
 public:
   Authenticator();
 
-  Authenticator(const std::string& machine,
-                const std::string& login,
-                const std::string& password,
-                const std::string& account);
+  Authenticator(std::string machine,
+                std::string login,
+                std::string password,
+                std::string account);
 
   virtual ~Authenticator();
 
@@ -73,61 +73,37 @@ public:
     return machine_;
   }
 
-  void setMachine(const std::string& machine);
-
-  template<typename InputIterator>
-  void setMachine(InputIterator first, InputIterator last)
-  {
-    machine_.assign(first, last);
-  }
+  void setMachine(std::string machine);
 
   const std::string& getLogin() const
   {
     return login_;
   }
 
-  void setLogin(const std::string& login);
-
-  template<typename InputIterator>
-  void setLogin(InputIterator first, InputIterator last)
-  {
-    login_.assign(first, last);
-  }
+  void setLogin(std::string login);
 
   const std::string& getPassword() const
   {
     return password_;
   }
 
-  void setPassword(const std::string& password);
-
-  template<typename InputIterator>
-  void setPassword(InputIterator first, InputIterator last)
-  {
-    password_.assign(first, last);
-  }
+  void setPassword(std::string password);
 
   const std::string& getAccount() const
   {
     return account_;
   }
 
-  void setAccount(const std::string& account);
-
-  template<typename InputIterator>
-  void setAccount(InputIterator first, InputIterator last)
-  {
-    account_.assign(first, last);
-  }
+  void setAccount(std::string account);
 };
 
 class DefaultAuthenticator : public Authenticator {
 public:
   DefaultAuthenticator();
 
-  DefaultAuthenticator(const std::string& login,
-                       const std::string& password,
-                       const std::string& account);
+  DefaultAuthenticator(std::string login,
+                       std::string password,
+                       std::string account);
 
   virtual ~DefaultAuthenticator();
 
@@ -136,9 +112,9 @@ public:
 
 class Netrc {
 private:
-  std::vector<std::shared_ptr<Authenticator> > authenticators_;
+  std::vector<std::unique_ptr<Authenticator>> authenticators_;
 
-  void storeAuthenticator(const std::shared_ptr<Authenticator>& authenticator);
+  void storeAuthenticator(std::unique_ptr<Authenticator> authenticator);
 public:
   Netrc();
 
@@ -146,15 +122,11 @@ public:
 
   void parse(const std::string& path);
 
-  std::shared_ptr<Authenticator> findAuthenticator
-  (const std::string& hostname) const;
+  const Authenticator* findAuthenticator(const std::string& hostname) const;
 
-  const std::vector<std::shared_ptr<Authenticator> >& getAuthenticators() const
-  {
-    return authenticators_;
-  }
+  const std::vector<std::unique_ptr<Authenticator>>& getAuthenticators() const;
 
-  void addAuthenticator(const std::shared_ptr<Authenticator>& authenticator);
+  void addAuthenticator(std::unique_ptr<Authenticator> authenticator);
 };
 
 } // namespace aria2
diff --git a/src/NetrcAuthResolver.cc b/src/NetrcAuthResolver.cc
index 04fcc9c1..593fd81e 100644
--- a/src/NetrcAuthResolver.cc
+++ b/src/NetrcAuthResolver.cc
@@ -35,42 +35,44 @@
 #include "NetrcAuthResolver.h"
 #include "AuthConfig.h"
 #include "Netrc.h"
+#include "a2functional.h"
 
 namespace aria2 {
 
-NetrcAuthResolver::NetrcAuthResolver():ignoreDefault_(false) {}
+NetrcAuthResolver::NetrcAuthResolver()
+  : netrc_(nullptr), ignoreDefault_(false) {}
 
-std::shared_ptr<AuthConfig>
+std::unique_ptr<AuthConfig>
 NetrcAuthResolver::resolveAuthConfig(const std::string& hostname)
 {
-  if(!getUserDefinedAuthConfig()) {
-    return findNetrcAuthenticator(hostname);
+  auto authConfig = getUserDefinedAuthConfig();
+  if(authConfig) {
+    return authConfig;
   } else {
-    return getUserDefinedAuthConfig();
+    return findNetrcAuthenticator(hostname);
   }
 }
 
-std::shared_ptr<AuthConfig>
+std::unique_ptr<AuthConfig>
 NetrcAuthResolver::findNetrcAuthenticator(const std::string& hostname) const
 {
   if(!netrc_) {
     return getDefaultAuthConfig();
   } else {
-    std::shared_ptr<Authenticator> auth = netrc_->findAuthenticator(hostname);
+    auto auth = netrc_->findAuthenticator(hostname);
     if(!auth) {
       return getDefaultAuthConfig();
     } else {
       if(ignoreDefault_ && auth->getMachine().empty()) {
         return getDefaultAuthConfig();
       } else {
-        return std::shared_ptr<AuthConfig>
-          (new AuthConfig(auth->getLogin(), auth->getPassword()));
+        return make_unique<AuthConfig>(auth->getLogin(), auth->getPassword());
       }
     }
   }
 }
 
-void NetrcAuthResolver::setNetrc(const std::shared_ptr<Netrc>& netrc)
+void NetrcAuthResolver::setNetrc(Netrc* netrc)
 {
   netrc_ = netrc;
 }
diff --git a/src/NetrcAuthResolver.h b/src/NetrcAuthResolver.h
index a92b5dff..d9b74acd 100644
--- a/src/NetrcAuthResolver.h
+++ b/src/NetrcAuthResolver.h
@@ -43,24 +43,19 @@ class Netrc;
 
 class NetrcAuthResolver : public AbstractAuthResolver {
 private:
-  std::shared_ptr<Netrc> netrc_;
+  Netrc* netrc_;
 
   bool ignoreDefault_;
 
-  std::shared_ptr<AuthConfig> findNetrcAuthenticator
+  std::unique_ptr<AuthConfig> findNetrcAuthenticator
   (const std::string& hostname) const;
 public:
   NetrcAuthResolver();
 
-  virtual std::shared_ptr<AuthConfig> resolveAuthConfig
+  virtual std::unique_ptr<AuthConfig> resolveAuthConfig
   (const std::string& hostname);
 
-  void setNetrc(const std::shared_ptr<Netrc>& netrc);
-
-  const std::shared_ptr<Netrc>& getNetrc() const
-  {
-    return netrc_;
-  }
+  void setNetrc(Netrc* netrc);
 
   // Ignores default token of netrc
   void ignoreDefault();
diff --git a/test/AuthConfigFactoryTest.cc b/test/AuthConfigFactoryTest.cc
index 557bd51f..0ffe2632 100644
--- a/test/AuthConfigFactoryTest.cc
+++ b/test/AuthConfigFactoryTest.cc
@@ -44,15 +44,15 @@ void AuthConfigFactoryTest::testCreateAuthConfig_http()
   CPPUNIT_ASSERT(!factory.createAuthConfig(req, &option));
 
   // with Netrc
-  std::shared_ptr<Netrc> netrc(new Netrc());
-  netrc->addAuthenticator
-    (std::shared_ptr<Authenticator>(new Authenticator("localhost",
-                                                   "localhostuser",
-                                                   "localhostpass",
-                                                   "localhostacct")));
-  netrc->addAuthenticator
-    (std::shared_ptr<Authenticator>(new DefaultAuthenticator("default", "defaultpassword", "defaultaccount")));
-  factory.setNetrc(netrc);
+  auto netrc = make_unique<Netrc>();
+  netrc->addAuthenticator(make_unique<Authenticator>("localhost",
+                                                     "localhostuser",
+                                                     "localhostpass",
+                                                     "localhostacct"));
+  netrc->addAuthenticator(make_unique<DefaultAuthenticator>("default",
+                                                            "defaultpassword",
+                                                            "defaultaccount"));
+  factory.setNetrc(std::move(netrc));
 
   // not activated
   CPPUNIT_ASSERT(!factory.createAuthConfig(req, &option));
@@ -100,15 +100,15 @@ void AuthConfigFactoryTest::testCreateAuthConfig_httpNoChallenge()
   CPPUNIT_ASSERT(!factory.createAuthConfig(req, &option));
 
   // with Netrc
-  std::shared_ptr<Netrc> netrc(new Netrc());
-  netrc->addAuthenticator
-    (std::shared_ptr<Authenticator>(new Authenticator("localhost",
-                                                   "localhostuser",
-                                                   "localhostpass",
-                                                   "localhostacct")));
-  netrc->addAuthenticator
-    (std::shared_ptr<Authenticator>(new DefaultAuthenticator("default", "defaultpassword", "defaultaccount")));
-  factory.setNetrc(netrc);
+  auto netrc = make_unique<Netrc>();
+  netrc->addAuthenticator(make_unique<Authenticator>("localhost",
+                                                     "localhostuser",
+                                                     "localhostpass",
+                                                     "localhostacct"));
+  netrc->addAuthenticator(make_unique<DefaultAuthenticator>("default",
+                                                            "defaultpassword",
+                                                            "defaultaccount"));
+  factory.setNetrc(std::move(netrc));
 
   // not activated
   CPPUNIT_ASSERT_EQUAL(std::string("localhostuser:localhostpass"),
@@ -147,10 +147,11 @@ void AuthConfigFactoryTest::testCreateAuthConfig_ftp()
                        factory.createAuthConfig(req, &option)->getAuthText());
 
   // with Netrc
-  std::shared_ptr<Netrc> netrc(new Netrc());
-  netrc->addAuthenticator
-    (std::shared_ptr<Authenticator>(new DefaultAuthenticator("default", "defaultpassword", "defaultaccount")));
-  factory.setNetrc(netrc);
+  auto netrc = make_unique<Netrc>();
+  netrc->addAuthenticator(make_unique<DefaultAuthenticator>("default",
+                                                            "defaultpassword",
+                                                            "defaultaccount"));
+  factory.setNetrc(std::move(netrc));
   CPPUNIT_ASSERT_EQUAL(std::string("default:defaultpassword"),
                        factory.createAuthConfig(req, &option)->getAuthText());
 
@@ -179,12 +180,11 @@ void AuthConfigFactoryTest::testCreateAuthConfig_ftp()
 
   // Recreate netrc with entry for user aria2user
   netrc.reset(new Netrc());
-  netrc->addAuthenticator
-    (std::shared_ptr<Authenticator>(new Authenticator("localhost",
-                                                   "aria2user",
-                                                   "netrcpass",
-                                                   "netrcacct")));
-  factory.setNetrc(netrc);
+  netrc->addAuthenticator(make_unique<Authenticator>("localhost",
+                                                     "aria2user",
+                                                     "netrcpass",
+                                                     "netrcacct"));
+  factory.setNetrc(std::move(netrc));
   // This time, we can find same username "aria2user" in netrc, so the
   // password "netrcpass" is used, instead of "userDefinedPassword"
   CPPUNIT_ASSERT_EQUAL(std::string("aria2user:netrcpass"),
@@ -196,17 +196,14 @@ void AuthConfigFactoryTest::testCreateAuthConfig_ftp()
 }
 
 namespace {
-std::shared_ptr<AuthConfigFactory::BasicCred>
+std::unique_ptr<BasicCred>
 createBasicCred(const std::string& user,
                 const std::string& password,
                 const std::string& host, uint16_t port,
                 const std::string& path,
                 bool activated = false)
 {
-  std::shared_ptr<AuthConfigFactory::BasicCred> bc
-    (new AuthConfigFactory::BasicCred(user, password, host, port, path,
-                                      activated));
-  return bc;
+  return make_unique<BasicCred>(user, password, host, port, path, activated);
 }
 } // namespace
 
diff --git a/test/DefaultAuthResolverTest.cc b/test/DefaultAuthResolverTest.cc
index 547321bf..c0104d2d 100644
--- a/test/DefaultAuthResolverTest.cc
+++ b/test/DefaultAuthResolverTest.cc
@@ -12,9 +12,7 @@ class DefaultAuthResolverTest : public CppUnit::TestFixture {
   CPPUNIT_TEST(testResolveAuthConfig_with_userDefined);
   CPPUNIT_TEST_SUITE_END();
 private:
-  //NetrcHandle _netrc;
-  //std::shared_ptr<Option> _option;
-  std::shared_ptr<DefaultAuthResolver> resolver_;
+  std::unique_ptr<DefaultAuthResolver> resolver_;
 public:
   void setUp()
   {
@@ -22,8 +20,7 @@ public:
     //_option = new Option();
     resolver_.reset(new DefaultAuthResolver());
     //_factory->setOption(_option.get());
-    resolver_->setDefaultAuthConfig
-      (std::shared_ptr<AuthConfig>(new AuthConfig("foo", "bar")));
+    resolver_->setDefaultCred("foo", "bar");
   }
 
   void testResolveAuthConfig_without_userDefined();
@@ -35,16 +32,16 @@ CPPUNIT_TEST_SUITE_REGISTRATION( DefaultAuthResolverTest );
 
 void DefaultAuthResolverTest::testResolveAuthConfig_without_userDefined()
 {
-  std::shared_ptr<AuthConfig> authConfig = resolver_->resolveAuthConfig("localhost");
+  auto authConfig = resolver_->resolveAuthConfig("localhost");
   CPPUNIT_ASSERT_EQUAL(std::string("foo:bar"), authConfig->getAuthText());
 }
 
 void DefaultAuthResolverTest::testResolveAuthConfig_with_userDefined()
 {
-  resolver_->setUserDefinedAuthConfig
-    (std::shared_ptr<AuthConfig>(new AuthConfig("myname", "mypasswd")));
-  std::shared_ptr<AuthConfig> authConfig = resolver_->resolveAuthConfig("localhost");
-  CPPUNIT_ASSERT_EQUAL(std::string("myname:mypasswd"), authConfig->getAuthText());
+  resolver_->setUserDefinedCred("myname", "mypasswd");
+  auto authConfig = resolver_->resolveAuthConfig("localhost");
+  CPPUNIT_ASSERT_EQUAL(std::string("myname:mypasswd"),
+                       authConfig->getAuthText());
 }
 
 } // namespace aria2
diff --git a/test/NetrcAuthResolverTest.cc b/test/NetrcAuthResolverTest.cc
index 0a455b32..b1677fc1 100644
--- a/test/NetrcAuthResolverTest.cc
+++ b/test/NetrcAuthResolverTest.cc
@@ -1,8 +1,11 @@
 #include "NetrcAuthResolver.h"
+
+#include <cppunit/extensions/HelperMacros.h>
+
 #include "prefs.h"
 #include "Netrc.h"
 #include "AuthConfig.h"
-#include <cppunit/extensions/HelperMacros.h>
+#include "a2functional.h"
 
 namespace aria2 {
 
@@ -14,23 +17,24 @@ class NetrcAuthResolverTest : public CppUnit::TestFixture {
   CPPUNIT_TEST(testResolveAuthConfig_ignoreDefault);
   CPPUNIT_TEST_SUITE_END();
 private:
-  std::shared_ptr<Netrc> netrc_;
-  //std::shared_ptr<Option> _option;
-  std::shared_ptr<NetrcAuthResolver> resolver_;
+  std::unique_ptr<Netrc> netrc_;
+  std::unique_ptr<NetrcAuthResolver> resolver_;
 public:
   void setUp()
   {
     netrc_.reset(new Netrc());
-    netrc_->addAuthenticator
-      (std::shared_ptr<Authenticator>(new Authenticator("localhost", "name", "passwd", "account")));
-    netrc_->addAuthenticator
-      (std::shared_ptr<Authenticator>(new DefaultAuthenticator("default", "defaultpasswd", "defaultaccount")));
+    netrc_->addAuthenticator(make_unique<Authenticator>("localhost",
+                                                        "name",
+                                                        "passwd",
+                                                        "account"));
+    netrc_->addAuthenticator(make_unique<DefaultAuthenticator>
+                             ("default",
+                              "defaultpasswd",
+                              "defaultaccount"));
 
-    //_option = new Option();
     resolver_.reset(new NetrcAuthResolver());
-    resolver_->setNetrc(netrc_);
-    resolver_->setDefaultAuthConfig
-      (std::shared_ptr<AuthConfig>(new AuthConfig("foo", "bar")));
+    resolver_->setNetrc(netrc_.get());
+    resolver_->setDefaultCred("foo", "bar");
   }
 
   void testResolveAuthConfig_without_userDefined();
@@ -43,13 +47,14 @@ CPPUNIT_TEST_SUITE_REGISTRATION( NetrcAuthResolverTest );
 
 void NetrcAuthResolverTest::testResolveAuthConfig_without_userDefined()
 {
-  std::shared_ptr<AuthConfig> authConfig = resolver_->resolveAuthConfig("localhost");
+  auto authConfig = resolver_->resolveAuthConfig("localhost");
   CPPUNIT_ASSERT_EQUAL(std::string("name:passwd"), authConfig->getAuthText());
 
   authConfig = resolver_->resolveAuthConfig("mymachine");
-  CPPUNIT_ASSERT_EQUAL(std::string("default:defaultpasswd"), authConfig->getAuthText());
+  CPPUNIT_ASSERT_EQUAL(std::string("default:defaultpasswd"),
+                       authConfig->getAuthText());
 
-  resolver_->setNetrc(std::shared_ptr<Netrc>());
+  resolver_->setNetrc(nullptr);
   authConfig = resolver_->resolveAuthConfig("localhost");
   CPPUNIT_ASSERT_EQUAL(std::string("foo:bar"), authConfig->getAuthText());
 
@@ -57,28 +62,29 @@ void NetrcAuthResolverTest::testResolveAuthConfig_without_userDefined()
 
 void NetrcAuthResolverTest::testResolveAuthConfig_with_userDefined()
 {
-  resolver_->setUserDefinedAuthConfig
-    (std::shared_ptr<AuthConfig>(new AuthConfig("myname", "mypasswd")));
-  std::shared_ptr<AuthConfig> authConfig = resolver_->resolveAuthConfig("localhost");
-  CPPUNIT_ASSERT_EQUAL(std::string("myname:mypasswd"), authConfig->getAuthText());
+  resolver_->setUserDefinedCred("myname", "mypasswd");
+  auto authConfig = resolver_->resolveAuthConfig("localhost");
+  CPPUNIT_ASSERT_EQUAL(std::string("myname:mypasswd"),
+                       authConfig->getAuthText());
 
   authConfig = resolver_->resolveAuthConfig("mymachine");
-  CPPUNIT_ASSERT_EQUAL(std::string("myname:mypasswd"), authConfig->getAuthText());
+  CPPUNIT_ASSERT_EQUAL(std::string("myname:mypasswd"),
+                       authConfig->getAuthText());
 
-  resolver_->setNetrc(std::shared_ptr<Netrc>());
+  resolver_->setNetrc(nullptr);
   authConfig = resolver_->resolveAuthConfig("mymachine");
-  CPPUNIT_ASSERT_EQUAL(std::string("myname:mypasswd"), authConfig->getAuthText());
+  CPPUNIT_ASSERT_EQUAL(std::string("myname:mypasswd"),
+                       authConfig->getAuthText());
 }
 
 void NetrcAuthResolverTest::testResolveAuthConfig_ignoreDefault()
 {
   resolver_->ignoreDefault();
-  std::shared_ptr<AuthConfig> authConfig = resolver_->resolveAuthConfig("mirror");
+  auto authConfig = resolver_->resolveAuthConfig("mirror");
   CPPUNIT_ASSERT_EQUAL(std::string("foo:bar"), authConfig->getAuthText());
 
   resolver_->useDefault();
-  std::shared_ptr<AuthConfig> defAuthConfig =
-    resolver_->resolveAuthConfig("mirror");
+  auto defAuthConfig = resolver_->resolveAuthConfig("mirror");
   CPPUNIT_ASSERT_EQUAL(std::string("default:defaultpasswd"),
                        defAuthConfig->getAuthText());
 }
diff --git a/test/NetrcTest.cc b/test/NetrcTest.cc
index 90e27af2..5c83c5c5 100644
--- a/test/NetrcTest.cc
+++ b/test/NetrcTest.cc
@@ -4,6 +4,7 @@
 #include <cppunit/extensions/HelperMacros.h>
 
 #include "Exception.h"
+#include "a2functional.h"
 
 namespace aria2 {
 
@@ -35,34 +36,41 @@ CPPUNIT_TEST_SUITE_REGISTRATION( NetrcTest );
 void NetrcTest::testFindAuthenticator()
 {
   Netrc netrc;
-  netrc.addAuthenticator
-    (std::shared_ptr<Authenticator>(new Authenticator("host1", "tujikawa", "tujikawapasswd", "tujikawaaccount")));
-  netrc.addAuthenticator
-    (std::shared_ptr<Authenticator>(new Authenticator("host2", "aria2", "aria2password", "aria2account")));
-  netrc.addAuthenticator
-    (std::shared_ptr<Authenticator>(new Authenticator(".my.domain", "dmname", "dmpass", "dmaccount")));
-  netrc.addAuthenticator
-    (std::shared_ptr<Authenticator>(new DefaultAuthenticator("default", "defaultpassword", "defaultaccount")));
+  netrc.addAuthenticator(make_unique<Authenticator>("host1",
+                                                    "tujikawa",
+                                                    "tujikawapasswd",
+                                                    "tujikawaaccount"));
+  netrc.addAuthenticator(make_unique<Authenticator>("host2",
+                                                    "aria2",
+                                                    "aria2password",
+                                                    "aria2account"));
+  netrc.addAuthenticator(make_unique<Authenticator>(".my.domain",
+                                                    "dmname",
+                                                    "dmpass",
+                                                    "dmaccount"));
+  netrc.addAuthenticator(make_unique<DefaultAuthenticator>("default",
+                                                           "defaultpassword",
+                                                           "defaultaccount"));
 
-  std::shared_ptr<Authenticator> aria2auth = netrc.findAuthenticator("host2");
+  auto aria2auth = netrc.findAuthenticator("host2");
   CPPUNIT_ASSERT(aria2auth);
   CPPUNIT_ASSERT_EQUAL(std::string("aria2"), aria2auth->getLogin());
   CPPUNIT_ASSERT_EQUAL(std::string("aria2password"), aria2auth->getPassword());
   CPPUNIT_ASSERT_EQUAL(std::string("aria2account"), aria2auth->getAccount());
 
-  std::shared_ptr<Authenticator> defaultauth = netrc.findAuthenticator("host3");
+  auto defaultauth = netrc.findAuthenticator("host3");
   CPPUNIT_ASSERT(defaultauth);
   CPPUNIT_ASSERT_EQUAL(std::string("default"), defaultauth->getLogin());
-  CPPUNIT_ASSERT_EQUAL(std::string("defaultpassword"), defaultauth->getPassword());
-  CPPUNIT_ASSERT_EQUAL(std::string("defaultaccount"), defaultauth->getAccount());
+  CPPUNIT_ASSERT_EQUAL(std::string("defaultpassword"),
+                       defaultauth->getPassword());
+  CPPUNIT_ASSERT_EQUAL(std::string("defaultaccount"),
+                       defaultauth->getAccount());
 
-  std::shared_ptr<Authenticator> domainMatchAuth =
-    netrc.findAuthenticator("host3.my.domain");
+  auto domainMatchAuth = netrc.findAuthenticator("host3.my.domain");
   CPPUNIT_ASSERT(domainMatchAuth);
   CPPUNIT_ASSERT_EQUAL(std::string("dmname"), domainMatchAuth->getLogin());
 
-  std::shared_ptr<Authenticator> domainMatchAuth2 =
-    netrc.findAuthenticator("my.domain");
+  auto domainMatchAuth2 = netrc.findAuthenticator("my.domain");
   CPPUNIT_ASSERT(domainMatchAuth2);
   CPPUNIT_ASSERT_EQUAL(std::string("default"), domainMatchAuth2->getLogin());
 }
@@ -71,24 +79,25 @@ void NetrcTest::testParse()
 {
   Netrc netrc;
   netrc.parse(A2_TEST_DIR"/sample.netrc");
-  std::vector<std::shared_ptr<Authenticator> >::const_iterator itr =
-    netrc.getAuthenticators().begin();
+  auto itr = std::begin(netrc.getAuthenticators());
 
-  std::shared_ptr<Authenticator> tujikawaauth = *itr;
+  const auto& tujikawaauth = *itr;
   CPPUNIT_ASSERT(tujikawaauth);
   CPPUNIT_ASSERT_EQUAL(std::string("host1"), tujikawaauth->getMachine());
   CPPUNIT_ASSERT_EQUAL(std::string("tujikawa"), tujikawaauth->getLogin());
-  CPPUNIT_ASSERT_EQUAL(std::string("tujikawapassword"), tujikawaauth->getPassword());
-  CPPUNIT_ASSERT_EQUAL(std::string("tujikawaaccount"), tujikawaauth->getAccount());
+  CPPUNIT_ASSERT_EQUAL(std::string("tujikawapassword"),
+                       tujikawaauth->getPassword());
+  CPPUNIT_ASSERT_EQUAL(std::string("tujikawaaccount"),
+                       tujikawaauth->getAccount());
   ++itr;
-  std::shared_ptr<Authenticator> aria2auth = *itr;
+  const auto& aria2auth = *itr;
   CPPUNIT_ASSERT(aria2auth);
   CPPUNIT_ASSERT_EQUAL(std::string("host2"), aria2auth->getMachine());
   CPPUNIT_ASSERT_EQUAL(std::string("aria2"), aria2auth->getLogin());
   CPPUNIT_ASSERT_EQUAL(std::string("aria2password"), aria2auth->getPassword());
   CPPUNIT_ASSERT_EQUAL(std::string("aria2account"), aria2auth->getAccount());
   ++itr;
-  std::shared_ptr<Authenticator> defaultauth = *itr;
+  const auto& defaultauth = *itr;
   CPPUNIT_ASSERT(defaultauth);
   CPPUNIT_ASSERT_EQUAL(std::string("anonymous"), defaultauth->getLogin());
   CPPUNIT_ASSERT_EQUAL(std::string("ARIA2@USER"), defaultauth->getPassword());