diff --git a/src/protocol-detail/challenge.cpp b/src/protocol-detail/challenge.cpp
index 847f7db..0116923 100644
--- a/src/protocol-detail/challenge.cpp
+++ b/src/protocol-detail/challenge.cpp
@@ -24,7 +24,7 @@
 namespace ndncert {
 
 Block
-CHALLENGE::encodeDataPayload(const RequestState& request)
+CHALLENGE::encodeDataPayload(const CaState& request)
 {
   Block response = makeEmptyBlock(tlv_encrypted_payload);
   response.push_back(makeNonNegativeIntegerBlock(tlv_status, static_cast<size_t>(request.m_status)));