diff --git a/src/detail/ca-memory.hpp b/src/detail/ca-memory.hpp
index 594875b..b4cdb97 100644
--- a/src/detail/ca-memory.hpp
+++ b/src/detail/ca-memory.hpp
@@ -25,6 +25,7 @@
 
 namespace ndn {
 namespace ndncert {
+namespace ca {
 
 class CaMemory : public CaStorage
 {
@@ -36,31 +37,32 @@
   /**
    * @throw if request cannot be fetched from underlying data storage
    */
-  CaState
+  RequestState
   getRequest(const RequestID& requestId) override;
 
   /**
    * @throw if there is an existing request with the same request ID
    */
   void
-  addRequest(const CaState& request) override;
+  addRequest(const RequestState& request) override;
 
   void
-  updateRequest(const CaState& request) override;
+  updateRequest(const RequestState& request) override;
 
   void
   deleteRequest(const RequestID& requestId) override;
 
-  std::list<CaState>
+  std::list<RequestState>
   listAllRequests() override;
 
-  std::list<CaState>
+  std::list<RequestState>
   listAllRequests(const Name& caName) override;
 
 private:
-  std::map<RequestID, CaState> m_requests;
+  std::map<RequestID, RequestState> m_requests;
 };
 
+} // namespace ca
 } // namespace ndncert
 } // namespace ndn