diff --git a/src/security/pib/pib-impl.hpp b/src/security/pib/pib-impl.hpp
index dc384a8..ba72466 100644
--- a/src/security/pib/pib-impl.hpp
+++ b/src/security/pib/pib-impl.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2013-2017 Regents of the University of California.
+/*
+ * Copyright (c) 2013-2018 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -23,9 +23,10 @@
 #define NDN_SECURITY_PIB_PIB_IMPL_HPP
 
 #include "pib.hpp"
-#include <set>
 #include "../v2/certificate.hpp"
 
+#include <set>
+
 namespace ndn {
 namespace security {
 namespace pib {
@@ -48,11 +49,7 @@
   class Error : public std::runtime_error
   {
   public:
-    explicit
-    Error(const std::string& what)
-      : std::runtime_error(what)
-    {
-    }
+    using std::runtime_error::runtime_error;
   };
 
 public:
diff --git a/src/security/pib/pib-memory.hpp b/src/security/pib/pib-memory.hpp
index 1252909..5331c7f 100644
--- a/src/security/pib/pib-memory.hpp
+++ b/src/security/pib/pib-memory.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2013-2017 Regents of the University of California.
+/*
+ * Copyright (c) 2013-2018 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -37,17 +37,6 @@
 class PibMemory : public PibImpl
 {
 public:
-  class Error : public PibImpl::Error
-  {
-  public:
-    explicit
-    Error(const std::string& what)
-      : PibImpl::Error(what)
-    {
-    }
-  };
-
-public:
   /**
    * @brief Create memory based PIB backend
    * @param location Not used (required by the PIB-registration interface)
diff --git a/src/security/pib/pib.hpp b/src/security/pib/pib.hpp
index 27d83da..3be9870 100644
--- a/src/security/pib/pib.hpp
+++ b/src/security/pib/pib.hpp
@@ -56,11 +56,7 @@
   class Error : public std::runtime_error
   {
   public:
-    explicit
-    Error(const std::string& what)
-      : std::runtime_error(what)
-    {
-    }
+    using std::runtime_error::runtime_error;
   };
 
 public: