diff --git a/ndn-cpp/security/identity/identity-storage.hpp b/ndn-cpp/security/identity/identity-storage.hpp
index 8b06e2a..52ec3b4 100644
--- a/ndn-cpp/security/identity/identity-storage.hpp
+++ b/ndn-cpp/security/identity/identity-storage.hpp
@@ -127,7 +127,7 @@
    * @param allowAny If false, only a valid certificate will be returned, otherwise validity is disregarded.
    * @return The requested certificate.
    */
-  virtual ptr_lib::shared_ptr<Data> 
+  virtual ptr_lib::shared_ptr<Certificate> 
   getCertificate(const Name &certificateName, bool allowAny = false) = 0;
 
 
diff --git a/ndn-cpp/security/identity/memory-identity-storage.cpp b/ndn-cpp/security/identity/memory-identity-storage.cpp
index a70c339..a7acf84 100644
--- a/ndn-cpp/security/identity/memory-identity-storage.cpp
+++ b/ndn-cpp/security/identity/memory-identity-storage.cpp
@@ -118,7 +118,7 @@
 #endif
 }
 
-ptr_lib::shared_ptr<Data> 
+ptr_lib::shared_ptr<Certificate> 
 MemoryIdentityStorage::getCertificate(const Name &certificateName, bool allowAny)
 {
 #if 1
diff --git a/ndn-cpp/security/identity/memory-identity-storage.hpp b/ndn-cpp/security/identity/memory-identity-storage.hpp
index 535aa76..b5b085a 100644
--- a/ndn-cpp/security/identity/memory-identity-storage.hpp
+++ b/ndn-cpp/security/identity/memory-identity-storage.hpp
@@ -122,7 +122,7 @@
    * @param allowAny If false, only a valid certificate will be returned, otherwise validity is disregarded.
    * @return The requested certificate.
    */
-  virtual ptr_lib::shared_ptr<Data> 
+  virtual ptr_lib::shared_ptr<Certificate> 
   getCertificate(const Name &certificateName, bool allowAny = false);