diff --git a/src/challenge-module/challenge-email.cpp b/src/challenge-module/challenge-email.cpp
index e475b24..b22ec93 100644
--- a/src/challenge-module/challenge-email.cpp
+++ b/src/challenge-module/challenge-email.cpp
@@ -28,7 +28,7 @@
 
 _LOG_INIT(ndncert.ChallengeEmail);
 
-NDNCERT_REGISTER_CHALLENGE(ChallengeEmail, "Email");
+NDNCERT_REGISTER_CHALLENGE(ChallengeEmail, "email");
 
 const std::string ChallengeEmail::NEED_CODE = "need-code";
 const std::string ChallengeEmail::WRONG_CODE = "wrong-code";
@@ -39,7 +39,7 @@
 ChallengeEmail::ChallengeEmail(const std::string& scriptPath,
                                const size_t& maxAttemptTimes,
                                const time::seconds secretLifetime)
-  : ChallengeModule("Email")
+  : ChallengeModule("email")
   , m_sendEmailScript(scriptPath)
   , m_maxAttemptTimes(maxAttemptTimes)
   , m_secretLifetime(secretLifetime)
diff --git a/src/challenge-module/challenge-pin.cpp b/src/challenge-module/challenge-pin.cpp
index 7de32f0..9534b21 100644
--- a/src/challenge-module/challenge-pin.cpp
+++ b/src/challenge-module/challenge-pin.cpp
@@ -27,14 +27,14 @@
 
 _LOG_INIT(ndncert.challenge-pin);
 
-NDNCERT_REGISTER_CHALLENGE(ChallengePin, "PIN");
+NDNCERT_REGISTER_CHALLENGE(ChallengePin, "pin");
 
 const std::string ChallengePin::NEED_CODE = "need-code";
 const std::string ChallengePin::WRONG_CODE = "wrong-code";
 const std::string ChallengePin::JSON_PIN_CODE = "pin-code";
 
 ChallengePin::ChallengePin(const size_t& maxAttemptTimes, const time::seconds& secretLifetime)
-  : ChallengeModule("PIN")
+  : ChallengeModule("pin")
   , m_secretLifetime(secretLifetime)
   , m_maxAttemptTimes(maxAttemptTimes)
 {