diff --git a/src/protocol-detail/challenge.cpp b/src/protocol-detail/challenge.cpp
index 61a3519..85875fd 100644
--- a/src/protocol-detail/challenge.cpp
+++ b/src/protocol-detail/challenge.cpp
@@ -19,8 +19,6 @@
  */
 
 #include "challenge.hpp"
-#include "../ndncert-common.hpp"
-#include "../request-state.hpp"
 
 namespace ndn {
 namespace ndncert {
diff --git a/src/protocol-detail/error.cpp b/src/protocol-detail/error.cpp
index b74180b..dabfa6a 100644
--- a/src/protocol-detail/error.cpp
+++ b/src/protocol-detail/error.cpp
@@ -37,16 +37,11 @@
 ErrorTLV::decodefromDataContent(const Block& block)
 {
   block.parse();
+  if (block.find(tlv_error_code) == block.elements_end()) {
+    return std::make_tuple(ErrorCode::NO_ERROR, "");
+  }
   ErrorCode error = static_cast<ErrorCode>(readNonNegativeInteger(block.get(tlv_error_code)));
-  auto description = readString(block.get(tlv_error_info));
-  return std::make_tuple(error, description);
-}
-
-bool
-ErrorTLV::isErrorContent(const Block& block)
-{
-  block.parse();
-  return block.find(tlv_error_code) != block.elements_end();
+  return std::make_tuple(error, readString(block.get(tlv_error_info)));
 }
 
 }  // namespace ndncert
diff --git a/src/protocol-detail/error.hpp b/src/protocol-detail/error.hpp
index d39fe1a..8a2cda0 100644
--- a/src/protocol-detail/error.hpp
+++ b/src/protocol-detail/error.hpp
@@ -39,9 +39,6 @@
    */
   static std::tuple<ErrorCode, std::string>
   decodefromDataContent(const Block& block);
-
-  static bool
-  isErrorContent(const Block& block);
 };
 
 }  // namespace ndncert
diff --git a/src/protocol-detail/info.cpp b/src/protocol-detail/info.cpp
index 06eba0e..7c0e449 100644
--- a/src/protocol-detail/info.cpp
+++ b/src/protocol-detail/info.cpp
@@ -24,7 +24,7 @@
 namespace ndncert {
 
 Block
-INFO::encodeDataContent(const CaConfigItem& caConfig, const security::v2::Certificate& certificate)
+INFO::encodeDataContent(const CaProfile& caConfig, const security::v2::Certificate& certificate)
 {
   auto content = makeEmptyBlock(tlv::Content);
   content.push_back(makeNestedBlock(tlv_ca_prefix, caConfig.m_caPrefix));
@@ -48,10 +48,10 @@
   return content;
 }
 
-CaConfigItem
+CaProfile
 INFO::decodeDataContent(const Block& block)
 {
-  CaConfigItem result;
+  CaProfile result;
   block.parse();
   for (auto const& item : block.elements()) {
     switch (item.type()) {
diff --git a/src/protocol-detail/info.hpp b/src/protocol-detail/info.hpp
index 03f0d61..571d120 100644
--- a/src/protocol-detail/info.hpp
+++ b/src/protocol-detail/info.hpp
@@ -32,12 +32,12 @@
    * Encode CA configuration and its certificate into a TLV block as INFO Data packet content.
    */
   static Block
-  encodeDataContent(const CaConfigItem& caConfig, const security::v2::Certificate& certificate);
+  encodeDataContent(const CaProfile& caConfig, const security::v2::Certificate& certificate);
 
   /**
    * Decode CA configuration from the TLV block of INFO Data packet content.
    */
-  static CaConfigItem
+  static CaProfile
   decodeDataContent(const Block& block);
 };