diff --git a/src/challenge-module/challenge-credential.cpp b/src/challenge-module/challenge-credential.cpp
index a41aa56..7102434 100644
--- a/src/challenge-module/challenge-credential.cpp
+++ b/src/challenge-module/challenge-credential.cpp
@@ -74,7 +74,7 @@
 
 // For CA
 std::tuple<ErrorCode, std::string>
-ChallengeCredential::handleChallengeRequest(const Block& params, CertificateRequest& request)
+ChallengeCredential::handleChallengeRequest(const Block& params, RequestState& request)
 {
   params.parse();
   if (m_trustAnchors.empty()) {
diff --git a/src/challenge-module/challenge-credential.hpp b/src/challenge-module/challenge-credential.hpp
index 93838a8..e356289 100644
--- a/src/challenge-module/challenge-credential.hpp
+++ b/src/challenge-module/challenge-credential.hpp
@@ -53,7 +53,7 @@
 
   // For CA
   std::tuple<ErrorCode, std::string>
-  handleChallengeRequest(const Block& params, CertificateRequest& request) override;
+  handleChallengeRequest(const Block& params, RequestState& request) override;
 
   // For Client
   std::vector<std::tuple<std::string, std::string>>
diff --git a/src/challenge-module/challenge-email.cpp b/src/challenge-module/challenge-email.cpp
index 2e9e133..327fb79 100644
--- a/src/challenge-module/challenge-email.cpp
+++ b/src/challenge-module/challenge-email.cpp
@@ -45,7 +45,7 @@
 
 // For CA
 std::tuple<ErrorCode, std::string>
-ChallengeEmail::handleChallengeRequest(const Block& params, CertificateRequest& request)
+ChallengeEmail::handleChallengeRequest(const Block& params, RequestState& request)
 {
   params.parse();
   auto currentTime = time::system_clock::now();
@@ -159,7 +159,7 @@
 
 void
 ChallengeEmail::sendEmail(const std::string& emailAddress, const std::string& secret,
-                          const CertificateRequest& request) const
+                          const RequestState& request) const
 {
   std::string command = m_sendEmailScript;
   command += " \"" + emailAddress + "\" \"" + secret + "\" \"" + request.m_caPrefix.toUri() + "\" \"" + request.m_cert.getName().toUri() + "\"";
diff --git a/src/challenge-module/challenge-email.hpp b/src/challenge-module/challenge-email.hpp
index 42a329d..f853e95 100644
--- a/src/challenge-module/challenge-email.hpp
+++ b/src/challenge-module/challenge-email.hpp
@@ -22,8 +22,6 @@
 #define NDNCERT_CHALLENGE_EMAIL_HPP
 
 #include "../challenge-module.hpp"
-#include <ndn-cxx/util/time.hpp>
-#include <ndn-cxx/encoding/block.hpp>
 
 namespace ndn {
 namespace ndncert {
@@ -59,7 +57,7 @@
 
   // For CA
   std::tuple<ErrorCode, std::string>
-  handleChallengeRequest(const Block& params, CertificateRequest& request) override;
+  handleChallengeRequest(const Block& params, RequestState& request) override;
 
   // For Client
   std::vector<std::tuple<std::string, std::string>>
@@ -75,7 +73,7 @@
 
   void
   sendEmail(const std::string& emailAddress, const std::string& secret,
-            const CertificateRequest& request) const;
+            const RequestState& request) const;
 
 PUBLIC_WITH_TESTS_ELSE_PRIVATE:
   // challenge status
diff --git a/src/challenge-module/challenge-pin.cpp b/src/challenge-module/challenge-pin.cpp
index caad97d..4853eed 100644
--- a/src/challenge-module/challenge-pin.cpp
+++ b/src/challenge-module/challenge-pin.cpp
@@ -41,7 +41,7 @@
 
 // For CA
 std::tuple<ErrorCode, std::string>
-ChallengePin::handleChallengeRequest(const Block& params, CertificateRequest& request)
+ChallengePin::handleChallengeRequest(const Block& params, RequestState& request)
 {
   params.parse();
   auto currentTime = time::system_clock::now();
diff --git a/src/challenge-module/challenge-pin.hpp b/src/challenge-module/challenge-pin.hpp
index 9e7d8b0..0b73cb2 100644
--- a/src/challenge-module/challenge-pin.hpp
+++ b/src/challenge-module/challenge-pin.hpp
@@ -22,7 +22,6 @@
 #define NDNCERT_CHALLENGE_PIN_HPP
 
 #include "../challenge-module.hpp"
-#include <ndn-cxx/util/time.hpp>
 
 namespace ndn {
 namespace ndncert {
@@ -53,7 +52,7 @@
 
   // For CA
   std::tuple<ErrorCode, std::string>
-  handleChallengeRequest(const Block& params, CertificateRequest& request) override;
+  handleChallengeRequest(const Block& params, RequestState& request) override;
 
   // For Client
   std::vector<std::tuple<std::string, std::string>>